AND

Exhibit 10.34
*CONTRACT FOR THE
USE AND MAINTENANCE OF A
FIBRE OPTIC NETWORK
(TRUNK NETWORK)

BETWEEN

RED NACIONAL DE LOS FERROCARRILES ESPANOLES (RENFE)

AND

FIRSTMARK COMMUNICATIONS EUROPE, S.A.

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* Portions of this agreement are confidential and have been omitted and filed
separately with the Securities and Exchange Commission pursuant to a request
for confidential treatment in accordance with Rule 406 under the Securities
Act of 1933, as amended. Asterisks, for example "***********", have been
inserted to indicate that information has been deleted.

In Madrid, 1 August 2000,

BETWEEN

Mr. Xxx Samples, of full age, acting for and behalf of FirstMark Communications
Europe, S.A., (hereinafter "FirstMark"), acting pursuant to the authority
granted to him as Chief Executive, and with address for the purposes hereof in
Luxembourg at 0 Xxx Xxxx Xxxxx, X-0000, Xxxxxxxxxx, of the one part,

and

Xx. Xxxx Xxxxx Xxxxxx Escala, of full age, acting for and behalf of LA RED
NACIONAL DE LOS FERROCARRILES ESPANOLES (hereinafter "RENFE"), acting pursuant
to the authority granted to him as Corporate Chief Executive, and with address
for the purposes hereof at Xxxx. Xxx XXX, 000, 00000 Xxxxxx,

and Xx. Xxxxxxx Xxxxxx Xxxxxxxx, of full age, acting for and on behalf of RENFE,
pursuant to the authority granted to him as Corporate Head of Development,
Planning and Management Control, with address for the purposes hereof at Xxxx.
Xxx XXX, 000, 00000 Xxxxxx, of the other part.

ACTING IN THE FOLLOWING CAPACITIES

The former acting on behalf of FirstMark, a Luxembourg company with registered
office in Luxembourg at 0 Xxx Xxxx Xxxxx, X-0000, Xxxxxxxxxx, registered in the
Luxembourg Chamber of Commerce under number 65610 Section B on 7 August 1998,
and

the latter acting on behalf of RENFE, with registered office at Xxxx. Xxx XXX,
000, 00000 Xxxxxx, a public corporation governed by its bylaws promulgated by
Spanish Royal Decree 121/1994, of 28 January, and with Fiscal ID Document
number, 28016749,

hereinafter referred to as the "Parties".

WHEREAS

ONE: RENFE is the owner of a fibre optic network over its rail infrastructure,
of substantial extent, capacity and quality.

TWO: RENFE holds the corresponding licence (C1) enabling it to grant the right
to use the fibre optic network covered by this contract.

THREE: RENFE wishes to grant to FirstMark to right to use the fibre optic
network as requested by the same. RENFE furthermore, in accordance with the
provisions of this contract, will be responsible for maintenance of the fibre
optic network the use of which is granted to FirstMark.

FOUR: FirstMark, through LAMBDANET, is implementing a fibre optic network in
Europe and wishes to extend the same to Spain.

FIVE: FirstMark wishes to lease a Fibre Optic Network (the "Network") from RENFE
to support its own transmission network or for the purpose of leasing capacity
to third parties.

IT IS HEREBY AGREED AS FOLLOWS

ONE. SUBJECT MATTER OF THE CONTRACT

1.1 The subject matter of this Contract is the grant by RENFE to FirstMark
of the right to use a Network consisting of 2 fibres over the layout
indicated in Annex 1, maintenance by RENFE of the said Network on the
terms set out in this contract, grant of the necessary rights for the
installation of equipment over the layout of the Network, and the
leasing of physical space and/or technical areas within RENFE premises
for appropriate use of the Network covered by the grant.

This Contract shall allow for subsequent extensions to be made to the
Network leased, or sections thereof contracted by FirstMark, on the
terms set out herein or which the parties may freely agree on in the
future.

1.2 The Network shall consist of several links which interconnect urban
centres where FirstMark has a point of presence. The same includes
points of presence, connection or others in RENFE stations within urban
nuclei through which the layout of the Network passes and which
FirstMark may request, even when there are several stations in a single
town or city. Each link is achieved with successive segments of dark
fibre pairs installed along the RENFE rail layout with intermediate
Telecommunications Parks used by FirstMark.

1.3 The Network consists of 2 fibres over the said layout, with the dates
of delivery and availability to FirstMark being as indicated in Annex
1.

TWO. DURATION OF THE CONTRACT

2.1 This Contract shall remain in force from signature hereof until twelve
years have elapsed from the date of delivery of the whole of the
Network detailed in Annex 1. The said initial duration may be extended
at the election of FirstMark for 2 periods, an initial period of 3
years and a further subsequent period of 5 years.

2.2. RENFE shall make the Network available to FirstMark (including the
modules detailed in Clause 3.4) prior to the delivery dates indicated
in Annex 1, on the dates also indicated in Annex 1.

2.3 In the event that FirstMark decides not to take up either of the two
extensions, it shall give six months notice thereof prior to the end of
the corresponding period to RENFE.

2.4. At the end of the second extension, as the case may be, this Contract
may be extended by mutual agreement between the parties.

THREE. OBLIGATIONS OF RENFE

Without prejudice to the provisions of other clauses of this Contract or the
Annexes hereto,

3.1 RENFE undertakes to make use of the Network available to FirstMark
within the agreed dates in accordance with the provisions of Clause
1.3.

3.2 RENFE undertakes to FirstMark to guarantee continuity and quality
between repeaters of the fibres leased and to guarantee the existence
and maintenance for the duration of this Contract and extensions
hereto, as the case may be, of rights of passage and easements required
for the said installations and for full implementation of the grant of
use pursuant to this Contract. RENFE in any event undertakes to
FirstMark that it shall have peaceful enjoyment of its right to use the
Network for the whole period of the Contract and any extensions hereto.

3.3 RENFE undertakes to undertake all repairs to the leased Network and
connected installations as may be necessary in order to preserve the
same in good condition of use by FirstMark in accordance with the
specifications contained in the Annexes to this Contract.

3.4 RENFE undertakes to grant FirstMark the right to install intermediate
repeater equipment and terminal equipment in a 3.6(m2) module per
repeater or terminal equipment, in the Telecommunications Parks
described on the FirstMark network map (Annex 1) over the layout of the
Network, the right to segregate the capacity produced at the
corresponding points and make use of the same for such services and
users as it deems fit, and the right to sell or transfer such capacity
to third parties under any legal arrangement.

3.5. RENFE undertakes to grant FirstMark the right to install antennae,
masts and complementary spaces for other equipment beyond that
described in the previous paragraph, as FirstMark considers necessary,
over the layout of the Network and whenever possible in the location
selected by FirstMark, on the following terms and conditions:

a) LOCATED WITHIN TELECOMMUNICATIONS PARKS

FirstMark may install, adjoining the FirstMark module, up to
two masts of up to 5 metres in height with a maximum of 5
antennae. FirstMark shall pay *********** annually to
RENFE for such installation (year 2000 price) which shall be
updated in accordance with the Consumer Price Index. FirstMark
may in individual cases request installation of a tower in the
Park which RENFE shall allow, in the absence of good reason,
on such technical and financial terms and conditions as may be
agreed.

b) LOCATED OUTSIDE TELECOMMUNICATIONS PARKS

On the technical, financial and administrative terms and
conditions as set out in the Framework Agreement and
individual Contracts negotiated between FirstMark and RENFE
(UN Patrimonio).

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* Omitted and filed separately with the Securities and Exchange Commission
pursuant to a request for confidential treatment.

FOUR. OBLIGATIONS OF FIRSTMARK; FINANCIAL TERMS AND CONDITIONS

4.1 Payment for the right to use all of the links making up the Network
shall be single, indivisible and made quarterly in accordance with the
provisions of this Clause. Until the whole of the Network has been
accepted, however, payment of the corresponding amount for the use of
partial sections (provided that the parties have expressly agreed
thereto) which have been satisfactorily accepted shall be made at the
proportion of the corresponding portion in relation to the contracted
Network as a whole.

4.2. FINANCIAL TERMS AND CONDITIONS: FirstMark shall pay the corresponding
amounts to RENFE in respect of the following:

(a) CHARGE FOR USE OF THE NETWORK: The annual amount payable in
relation to the year 2000 for use of the whole of the Network,
as indicated in Annex 1, shall be **************************
************************************************************
****************************. The said charges shall include
those for the technical areas indicated in Clause 3.4. and
shall be applied in proportion to the sections delivered in
accordance with the provisions of Clause 4.1.

The said amounts shall be reviewed annually in line with the
Consumer Price Index, with the first review taking place on 01
January 2001.

The prices for each section indicated in Annex 1 shall relate
to a pair of optical fibres; in the event that FirstMark
requests an increase in capacity, the following discounts
shall be applied:

2(nd) pair ........................ ***
3(rd) pair ........................ ***
4(th) and successive pairs......... ***.

(b) MAINTENANCE CHARGE: The initial annual price payable for
maintenance shall be *** of the initial amount of rent for the
trunk network detailed in Annex 1. The annual maintenance
price shall be revised each year in line with the CPI - with
no restriction on the latter - as from 1/1/2001. Until the
whole of the Network is handed over, the applicable
maintenance charge shall be that solely in relation to that
portion of the Network handed over.

(c) CHARGE FOR NEW REPEATER MODULES. RENFE shall provide
additional models to those described in Clause 3.4 at points
where FirstMark so requests, whenever possible, at an annual
rental of **************** for each additional module, the
said amount relating to 2000 and revised each year on the
basis of the CPI.

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* Omitted and filed separately with the Securities and Exchange Commission
pursuant to a request for confidential treatment.

(d) RENTAL OF OTHER TECHNICAL PREMISES OR SPACES: The initial
rent for technical spaces shall be adjusted on a case by case
basis in accordance with market prices.

4.3. LIMIT ON ANNUAL CPI INCREASE Any increase agreed in this Contract based
on the CPI shall be limited to a maximum of ** annually. By way of
exception, this limit shall not apply in respect of maintenance charges
(Clause 4.2.b)) which shall be revised in line with the actual CPI.

4.4. PAYMENT TERMS Payment shall be made quarterly in arrears on the
following fixed dates: 15 January, 15 April, 15 July and 15 October.
Until the whole of the Network has been handed over, invoicing shall
relate to that part of the Network handed over and for the days of the
corresponding invoicing quarter which elapse between the date of
delivery and the corresponding invoicing date established. Payment of
quarterly invoices shall be made by transfer or payment into the bank
accounts of RENFE opened with banks BBVA 0182-3994-07-0010190008 or
BSCH 0049-1500-00-2010132343 at thirty days of invoice date.

FIVE. FIRSTMARK PROTECTION CLAUSE

5.1 In relation to the Network as a whole or by sections, RENFE undertakes
to offer at all times to FirstMark such terms and conditions (financial
and service) for the right to use the Network which ensure that no
other RENFE fibre optic customer enjoys better terms and conditions in
respect of the sections making up the Network.

5.2 Modifications to the Network rental price in respect of FirstMark shall
be made based on the Network sections used by such other customer such
that FirstMark shall benefit only from the most favourable prices on
such sections, consequently reducing the total price for leasing the
Network by the said amount.

5.3. RENFE shall deliver to FirstMark the annual report prepared by the
auditors of RENFE certifying as to whether application of this clause
in each case in relation to the financial and service terms and
conditions set out in the Contract is in fact providing FirstMark with
the protection provided by this clause.

Likewise, after delivery of the Network, in the event that FirstMark
considers that the quality of service provided by RENFE is lower than
that in respect of other RENFE Customer Operators, it may request a
Technical Audit (a maximum of one annually). RENFE shall carry out, at
its own cost, a Technical Audit through an undertaking of

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* Omitted and filed separately with the Securities and Exchange Commission
pursuant to a request for confidential treatment.

acknowledged prestige and solvency to analyse the complaint raised by
FirstMark based on a Protocol which shall be agreed between FirstMark
and RENFE within 6 weeks from the date of request by FirstMark for the
Technical Audit.

In the event that any of the audits (both that relating to financial
and service terms and conditions contractually stipulated, as well as
that relating to service quality provided in Network operation) reveals
that FirstMark does not have the status of most favoured Customer,
RENFE shall restore the said status in respect of any of the financial
or service quality aspects within a maximum of 3 months from the date
of the audit report.

5.4. RENFE shall deliver the audit reports prepared within a maximum of 15
days from the date they are available to RENFE.

SIX. RULES GOVERNING INITIAL ACCEPTANCE, STAGES, EXTENSIONS AND
REDUCTIONS

6.1 The Loops or routes which constitute the Network shall be accepted by
FirstMark as from the stipulated delivery date if the verification and
acceptance requirements set out in this Contract are complied with. At
such time the corresponding Delivery Certificate in respect of each
Loop or route shall be signed by both parties in accordance with the
model attached as Annex 5.

6.2 All verification and acceptance tests for the suitability of the routes
making up the Network shall be subject to the Technical Agreement
included as Annex 3 to this contract. The said Agreement in any event
details the standards applicable to the activities of FirstMark in this
respect, which both parties accept as being consistent with those in
the industry.

6.3 Rent shall begin to accrue as from the date of delivery to FirstMark of
the Network, or part of the Network either because the Network has been
previously jointly measured and accepted by FirstMark or because
FirstMark has previously carried out the checks which it considers
appropriate in accordance with the provisions of Clauses 4.1 and 4.3
and without prejudice to the provisions of 6.4.

6.4 Delays and Penalties / Advances and Allowances. The parties hereby
declare that it is their intention to comply with the agreed delivery
and availability dates, without prejudice to their express intention to
make all necessary efforts to advance the agreed delivery dates. Delays
within an interval of less than two weeks in relation to the agreed
availability date shall be deemed acceptable. Delays exceeding two
weeks shall be subject to the penalties specified in Annex 2. If part
of the Network is advanced, payment shall be proportional to the
portion of the Network delivered to FirstMark.

6.5 In the case of newly constructed sections, after signature of this
Contract either party may propose agreed extensions, reductions, delays
or advances, which shall be resolved on the principle of good faith,
provided that the total cumulative volume of modifications does not
affect more than 5% of the kilometres contracted. In this case, the
rent for the Network shall increase or decrease in proportion to the
contracted kilometres of fibre, at the price per kilometre contracted
by FirstMark from RENFE for the specified extension. In this respect,
FirstMark states its intention to extend its Network in the future to
the borders of FRANCE and PORTUGAL.

RENFE undertakes to notify FirstMark in writing of any possible
saturation of the RENFE Network cables which do not form part of the
Network leased to FirstMark, in order that FirstMark can request that
RENFE, within a maximum period of 3 months from the date of
notification from RENFE, grant the right to use optical fibre on
sections in which it may be interested.

6.6. At any time whilst this Contract remains in force, FirstMark may
replace part of the kilometres contracted with other routes of the
Network on which RENFE has available fibre and technical spaces, on
condition that the total number of new replacement kilometres is at
least 1.2 times the number of kilometres substituted as contracted at
that time. The prices to be applied to payment of the new kilometres
shall be those invoiced at that time to other Customers over the
sections in question, with the remaining terms and conditions of the
Contract remaining unaltered.

FirstMark shall notify RENFE in writing at least 6 months in advance of
its desire to switch contracted kilometres of fibre.

The removal of repeater equipment and/or nodes installed, and the
installation of equipment on the new route shall be for account of
FirstMark, along with payment for technical spaces in the event that
none exist.

If RENFE lays new cables with fibres having superior specifications to
the current fibres, FirstMark shall be entitled to switch fibres in use
for the said new fibres at the price agreed by the parties on the basis
that FirstMark retains its status as most favoured Customer.

6.7. If RENFE anticipates that the capacity of the cable is close to
exhaustion on any routes of the network leased to FirstMark (i.e. 62.5%
of capacity is taken up), it shall notify FirstMark thereof. FirstMark
shall be entitled to extend the capacity of optical fibre in the same
amount as it has leased from RENFE until that time in the said
direction. This option must be exercised by FirstMark within a maximum
of 3 months from the date of notification by RENFE; FirstMark shall be
granted a discount on the increase in capacity which it may request in
accordance with the provisions of the second paragraph of 4.2.a).

6.8. In the event that at any time after the cancellation - for any reason
by FirstMark of sections making up the Network, the Network does not
reach a length of at least 1,500 km, the unit prices to be applied to
the resulting Network shall - based on the length of the modified
network - be those indicated in Annex 1 (1.c) which shall be updated in
line with the CPI.

SEVEN. MEASUREMENTS AND VERIFICATIONS

7.1 RENFE shall carry out measurements, by the method and subject to the
requirements specified in Annex 4, and invite FirstMark in writing at
least 8 days in advance to attend at the RENFE measurement and/or to
carry out its own measurement, provided that availability of the fibre
is not delayed.

7.2 RENFE shall use its best efforts to carry out the suitability tests of
the Network which it has completed as soon as possible.

7.3 RENFE shall provide FirstMark with the results of measurement on the
date of total or partial availability, as the case may be, of the
Network, which shall comply with the technical requirements set out in
Annex 3 of this Contract. As from the said date of availability until
the date of delivery RENFE undertakes to maintain the quality standards
obtained.

EIGHT. MAINTENANCE

8.1 RENFE undertakes, pursuant to this contract, to maintain the Network
contracted by FirstMark, and the obligations and commitments of RENFE
in relation to interruptions in the service provided to FirstMark shall
thus be as referred to below.

(a) SERVICE CUTS FOR SCHEDULED WORK: The standard of preventative
maintenance shall be:

1 Less than one scheduled cut for each 200 km of Network
per year.

2 Maximum time out of service per scheduled cut of 2.5
hours plus the testing time as detailed in Annex 3 (1.5 hours).

3 In order to minimise interruptions to service as far
as possible, scheduled cuts shall be notified in writing by
RENFE at least 30 calendar days in advance.

4 Scheduled cuts shall - preferably - take place during the
night as a result of the minimum impact on FirstMark
operations, i.e. between midnight and 6 am. Furthermore, no
more than one scheduled cut shall be permitted on the same day
nor more than one cut per week in each Loop.

5 In order to prevent possible technical problems, confirmation
procedures shall be established prior to the cut. Thirty
minutes before the cut, RENFE will confirm the operation to
FirstMark in order to verify that the FirstMark Network or
that of other Customers is not in a catastrophic situation. If
this is the case, staff of suitable seniority shall negotiate
the conditions for a solution with is satisfactory to all
parties. In this respect, RENFE hereby states its intention
interrupt the scheduled cut if circumstances so permit on the
basic criterion of preventing serious loss to FirstMark.

6 The procedure to be followed in respect of technical
operations is described in Annex 3.

(b) CUTS IN SERVICE ON BREAKDOWN: The corrective maintenance standard shall
be:

1 Less than one breakdown for each 300 km of Network per
year.

2 Maximum time out of service on breakdown of 8 hours
plus the testing time as detailed in Annex 3 (1.5 hours).

3 The procedure to be followed for technical operations
is described in Annex 3.

8.2 Failure to comply with these parameters shall result in RENFE incurring
the penalties set out in Annex 2.

8.3 9.3 Interruptions in service as a result of force majeure shall be
excluded from the foregoing obligations. Force majeure shall mean any
cause beyond the reasonable control of RENFE which affects compliance
with its obligations, including cases of natural catastrophe,
insurrection and civil disorder, military operations or war, local or
national emergencies, acts or omissions of administrative or
governmental authorities, fire, flooding, lightening, explosion,
landslip, acts or omissions of persons or bodies for which RENFE is not
responsible, provided that such circumstances prevent RENFE from
restoring the service. Even in the event of delays or breakdowns for
these reasons, RENFE undertakes to use all necessary efforts to resolve
the problem, including on a provisional basis, in order to minimise the
negative repercussions for FirstMark which could result.

8.4 The parties agree that in respect of both the maintenance terms and
conditions and the agreed penalties, periods shall be applied over
consecutive periods of twelve months from the day on which the
obligation arises in respect of maintenance or the payment of
penalties.

8.5. RENFE undertakes to grant maintenance terms and conditions to FirstMark
such that no other RENFE fibre optic customer with similar service and
financial terms and conditions for the leasing of optical fibre and
maintenance enjoys better terms and conditions in respect of the
sections forming the subject matter of this contract.

NINE. OTHER TECHNICAL PREMISES

9.1 RENFE shall provide FirstMark with physical space or premises for
housing terminal and third party connection equipment in any railway
premises, except for good reason. Such premises shall in principle not
be made ready for this purpose; i.e. the installation of technical
roofs and ground structures, preparation of the premises, the supply of
energy, air-conditioning, security systems, etc., shall be for account
of FirstMark, and consequently the premises and ancillary items shall
be for the exclusive use of FirstMark. Access to such premises shall be
restricted; they may only be accessed by those determined by FirstMark
and by means of particular access control systems provided by
FirstMark. RENFE undertakes to collaborate fully with FirstMark in the
installation and fitting out of the said premises. FirstMark may, in
the absence of good reason and on the financial terms and conditions
which may be agreed, install masts and antennae on these premises or on
the buildings in which they are located.

9.2 The supplementary premises with equipment for access by FirstMark,
switching equipment and/or external installations, shall be dimensioned
in accordance with the requirements of FirstMark and shall be
additionally invoiced at market prices.

9.3 RENFE shall use all necessary efforts to provide FirstMark, if there is
available space and the latter so requests, with space or premises to
house offices, supervisory centre and for any other purpose which may
be agreed.

9.4. In premises in which only repeaters or minor equipment is housed, the
possibility of implementation of the installation by RENFE on a turnkey
basis shall be offered. If space is only required to house up to two
standard frames, such space shall be included in the price offered for
the right to use the Network and consequently no additional amount
shall be charged therefor. Access to such premises shall in any event
be restricted; they may only be accessed by those determined by
FirstMark and through particular access control systems provided by
FirstMark. In premises shared by RENFE

and FirstMark, those authorised by FirstMark to access the same shall
be determined jointly be FirstMark and RENFE.

9.5. In the event that RENFE leases physical space or premises to FirstMark
pursuant to this clause, the appropriate lease shall be entered into in
accordance with the provisions of this Clause 9.

9.6 The parties shall agree on the technical and access conditions of
cables, responsibility for external Network connection, and the
financial terms and conditions of such connection.

TEN. EXTERNAL CONNECTIONS

10.1. RENFE does not have access with optical fibres to urban areas outside
the railway environment. The fibre optic cable shall be made available
to FirstMark at the RENFE optical distributor at the
"Telecommunications Park" located in the station in each town and city
in question; on written request by FirstMark, however, RENFE shall
facilitate connection from the urban nodes of FirstMark to the said
"Telecommunications Parks", such that FirstMark gains access to the
layout by the most suitable path to it, and from that point RENFE shall
extend the cable to the optical distributor. The prices of such
extensions shall - for a cable of 16 f.o. - be ******* *******
annually/km in the case of overhead cable, and ******* *******
annually/km if buried or in conduits, at the option, in principle, of
FirstMark. A discount of *** shall be applied to the rental in respect
of such extensions in the 6(th) and successive years. The maintenance
cost of these cables shall be ***** *******/km/year. These prices shall
be updated annually in line with the CPI.

ELEVEN. TERMINATION OF THE CONTRACT

11.1 RENFE waives its entitlement pursuant to Section 1124 of the Civil Code
to terminate or rescind the Contract for any reason except for
persistent and deliberate default by FirstMark in payment, as provided
in this clause. In this event, deliberate delay in payment by FirstMark
shall entitle RENFE to seek termination of the Contract and
compensation for loss and damage of 30% of the remaining amount of the
Contract or any extension thereof, plus amounts pending payment, along
with the corresponding late payment interest as appropriate, at the 3
month MIBOR plus 1.5 points. For the purposes of this clause,
persistent and deliberate non-payment shall be deemed to occur

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* Omitted and filed separately with the Securities and Exchange Commission
pursuant to a request for confidential treatment.

if the same persists after written notice from RENFE granting a period
of ninety days to make the payment.

11.2. FirstMark may terminate or rescind the Contract in whole or in part
prior to the normal termination hereof, or of any extension hereto, and
if it does so without good reason it shall pay RENFE an amount by way
of damages of 30% of the remaining amount of the Contract, or of the
extension thereof, in respect of the section or sections which are
terminated.

Good reason shall mean any of the grounds indicated in Clause 11.3.

11.3 FirstMark may only terminate the Contract in whole or in part in the
event of substantial breach by RENFE, which termination shall take
place without penalty. Circumstances of substantial breach covered by
this Contract shall be as follows:

- Delay in the agreed delivery periods:
- Delay of more than 1 month in delivery of the
network or agreed sections of the Network.

- Scheduled cuts:
- More than 1 scheduled cut for each 100 km per year.
- X cuts (network km/200 km) of over 5 hours in a period of
one year.

- Breakdowns:
- Repetition of breakdowns, defined by more than 3
reakdowns in a single month (30 calendar days) on the
same 100 km section.
- X breakdowns (network km/300 km) of more than 24 hours in
duration each in a period of one year.

- Breakdowns and scheduled cuts:
- over 10 hours for each 100 km of network service
interruption in a period of one year. If the network length is
less than 500 km, the threshold shall be 50 hours.

- Fibre quality:
- Deterioration in the quality of fibres ascertained by tests
carried out by external experts, and not restored within a
period of one month.

- Delay exceeding 3 months in restoration by RENFE to
FirstMark of its status as most favoured Customer, in both
financial and service aspects, in accordance with the
provisions of 5.3.

The initial date for annual computation shall be the date of delivery
of the fibre.

Delays in delivery or breakdowns caused by force majeure shall be
excluded from the foregoing obligations.

In the event that for the reasons indicated in this clause FirstMark
requests total or partial termination of the Contract, RENFE shall, by
way of penalty, guarantee FirstMark use of the Network covered by
termination, at no charge, during a period equivalent to 30% of the
remaining period of the Contract up to 10 years or, if during a
contract extension, a period equivalent to 30% of the remaining period
until the end of the corresponding extension. In this respect, the
minimum guaranteed network usage period for the purpose of enabling
FirstMark to seek an alternative shall be one year.

11.4. FirstMark may terminate this Contract without penalty if, within six
months from the date of signature hereof, the parties do not sign the
Dedicated Network Contracts, Framework Agreement and Property Lease
based on the pro forma documents in the possession of FirstMark, as
provided in 3.5b).

TWELVE. ASSIGNMENT

12.1 RENFE shall retain full exclusive right to utilise, construct and
extend the network of cables as it deems fit, and to use of the
different metallic or optical conductors which make up the same; full
right to use the run laid, supports or conduits as it considers most
suitable to guarantee the quality of all services carried, both its own
and third party, and full right to segregate conductors for different
uses.

12.2 RENFE shall further be entitled to permit other third party
installations, transfer assets or rights and assign its contractual
position under this contract to third parties, provided that the same
belong to the RENFE Group and hold the corresponding individual licence
to grant right to use of a fibre optic network. It shall be deemed that
the third party is included in the said Group when any of the
circumstances apply to it as laid down in Section 4 of the Securities
Market Act (24/1988, of 28 July). RENFE shall in any event be jointly
and severally liable for obligations under this Contract even though it
assigns its contractual position to a third party in its Group.

12.3 The parties acknowledge the existence of the procedure for the
securitisation of assets permitted by law pursuant to Royal Decree
926/1998, of 14 May.

12.4 FirstMark expressly waives the right to assign use of the dark fibre
Network to a third party without the authorisation of RENFE. FirstMark
shall nevertheless be entitled to assign its contractual position under
this Contract to third parties, provided that they belong to the
FirstMark Group or to FIRSTMARK COMMUNICATIONS SPAIN, S.L. It shall be
deemed that the third party is part of the said Group when any of the
circumstances apply as laid down by Section 4 of the Securities Market
Act (24/1988, of 28 July). FirstMark shall in any event be jointly and
severally liable for obligations contracted hereunder even though it
assigns its contractual position to a third party forming part of its
Group.

12.5 Connection of the Network, or fibres of the Network, or the nodes which
exist in the said Network, by FirstMark to domestic and international
connections or for the purpose, service or object of domestic and
international connections, shall in no event be deemed to be resale of
dark fibre or assignment by FirstMark to third parties, and FirstMark
shall not in any event therefore require the consent of RENFE.

THIRTEEN. CONFIDENTIALITY

The parties undertake to maintain the terms of this contract and the parties
hereto in maximum confidence and secrecy, and shall not communicate this
information to any third party without the prior written permission of the other
party, which shall not be unreasonably withheld. The said prior permission shall
not be required if the information is required by or must be communicated to a
competent administrative, judicial or Stock Exchange authority.

For the purposes of the securitisation procedure referred to in Clause 11.3, on
notice by one of the parties of its desire to study the viability of the said
procedure, the permission of the other party shall not be necessary for the
purpose of communication of information in accordance with this Contract
provided that the third party to whom the information is to be communicated
signs the confidentiality undertaking included as Annex 6, and one original
thereof is delivered to the other party.

FOURTEEN. APPLICABLE LAW

This Contract shall be governed and interpreted in accordance with Spanish law.

FIFTEEN. ARBITRATION

The parties shall initially attempt to resolve any dispute, claim or litigation
arising out of or related to this Contract (a "Dispute") through negotiation in
good faith between the parties and if agreement is not possible by these means,
the parties expressly waive any jurisdiction which may apply to them and agree
to submit resolution of the Dispute to arbitration. The said arbitration shall
be at law and be administered by the Civil and Mercantile Arbitration Court
("CORTE CIVIL Y MERCANTIL DE ARBITRAJE - CIMA"), the Bylaws and Procedural
Regulations of which the parties are acquainted with. The hearing and
determination of disputes shall be entrusted to three arbitrators who shall be
appointed one each by the parties at the time the dispute arises and the third
by the Chairman of the CIMA in accordance with its Bylaws or Procedural Rules.
Arbitration shall take place in Madrid city, in Spanish, in accordance with
Spanish law. The parties irrevocably submit to the arbitration award issued and
hereby expressly record their agreement to abide by the same. The parties
further record that they shall abide by and act in accordance with interlocutory
decisions and measures ordered by the arbitrators in the same form and manner as
in the case of a final award.

SIXTEEN. ADDITIONAL UNDERTAKINGS

The parties undertake to negotiate in good faith provision by RENFE to FirstMark
of an additional number of fibres to satisfy the requirements of FirstMark in
the future.

SEVENTEEN. PENALTIES

The penalties detailed in Annex 2 incorporated herein shall apply to this
Contract.

EIGHTEEN. NOTICES

Any notice affecting the terms of this Contract shall be sent by fax and
registered post to the signatories hereof.

NINETEEN. CONDITION PRECEDENT

This Contract shall be conditional on ratification thereof by the respective
Boards of Directors, which must be provided within a maximum of 45 days from the
date of signature hereof.

ANNEXES

The following documents are incorporated herein as annexes and therefore form
and integral part of this contract for all purposes:

Annex 1 Description of the FirstMark Network and availability and
delivery dates.

Annex 2 Penalties.

Annex 3 Technical Agreement between RENFE and FirstMark for the
provision of optical fibres.

Annex 4 Verification and commissioning of fibre optic networks.

Annex 5 Certificate of handover of Network Loops or sections.

Annex 6 Confidentiality Undertaking.

In witness whereof, the undersigned have signed this contract in the place and
on the date indicated at the beginning.

For: Red Nacional de los For: FirstMark
Ferrocarriles Espanoles

(RENFE)

/s/ XXXX M(a) XXXXXX ESCALA /s/ XXX SAMPLES
--------------------------- --------------------------
Xxxx M(a) Xxxxxx Xxxxxx Xxx Samples
Corporate Chief Executive Chief Executive

/s/ XXXXXXX XXXXXX XXXXXXXX
---------------------------
Xxxxxxx Xxxxxx Xxxxxxxx
Corporate Head of Development,
Planning and Management Control

--------------------------------------------------------------------------------

*ANNEX 1

1.A. NETWORK TOPOLOGY

1.B. DESCRIPTION OF THE NETWORK: LOOPS, SECTIONS, AVAILABILITY
AND DELIVERY DATES

1.C. FIBRE OPTIC TRUNK NETWORKS. RENFE PRICES FOR 2000.

---------------
* Portions of this annex are confidential and have been omitted and filed
separately with the Securities and Exchange Commission pursuant to a request
for confidential treatment in accordance with Rule 406 under the Securities
Act of 1933, as amended. Asterisks, for example "***********", have been
inserted to indicate that information has been deleted.

[OBJECT OMITTED]
[MAP]

ANNEX 1.B

DEFINITION OF LOOPS AND ROUTES MAKING UP THE FIRST XXXX NETWORK
NETWORK VALUATION. 2000 PRICES. 1 FIBRE OPTIC PAIR

LOOP 1

------------------------------------------------------------------------------------------------------------------------------------
SECTION LENGTH (KM) AMOUNT OF ANNUAL RENTAL AVAILABILITY DATE DELIVERY DATE OBSERVATIONS
(MILLIONS OF PESETAS)
2000 TARIFFS
------------------------------------------------------------------------------------------------------------------------------------

MADRID-ALBACETE-CHINCHILLA .............. 296 ****** 00/Xxxxxx/00 0/Xxx/00
XXXXXXXXXX-XXXXXX-XXXXXXXX-XX ENCINA 320 ****** 15/August/00 1/Dec/00
XX XXXXXX-XXXXXXXX....................... 113 ****** 15/August/00 1/Dec/00
VALENCIA-BARCELONA....................... 361 ****** 15/August/00 1/Dec/00
BARCELONA-GERONA......................... 111 ****** 15/August/00 1/Dec/00
......................................... 277 ****** 15/August/00 1/Dec/00
GERONA-MANRESA-LERIDA ................... 189 ****** 15/August/00 1/Dec/00
LERIDA-ZARAGOZA.......................... 44 ****** 15/August/00 1/Dec/00
TARDIENTA-HUESCA (I/V)................... 445 ****** 15/August/00 1/Dec/00
XXXXXXXX-XXXXX-GUADALAJARA-MADRID.. 24 ****** 15/August/00 1/Dec/00
ELCHE-ALICANTE...........................

------------------------------------------------------------------------------------------------------------------------------------

SUBTOTAL 1 ......... 2.180 ******

---------------
* Omitted and filed separately with the Securities and Exchange Commission
pursuant to a request for confidential treatment.

DEFINITION OF LOOPS AND ROUTES MAKING UP THE FIRST XXXX NETWORK
NETWORK VALUATION. 2000 PRICES. 1 FIBRE OPTIC PAIR

LOOP 2

MADRID-CIUDAD REAL................... 171 ****** 15/August/00 1/Dec/00
CIUDAD REAL-CORDOBA.................. 175 ****** 00/Xxxxxx/00 0/Xxx/00
XXXXXXX-XXXXXXX-XXXXXX-XXXXXXX ...... 301 ****** 15/August/00 1/Dec/00
ESPELUY-JAEN (I/V)................... 64 ****** 15/August/00 1/Dec/00
XXXXXX-ALMERIA....................... 124 ****** 15/August/00 1/Dec/00
GRANADA-SEVILLA...................... 309 ****** 15/August/00 1/Dec/00
BOBADILLA-MALAGA (I/V)............... 138 ****** 15/August/00 1/Dec/00
XXXXXX-XXXXX (I/V)................... 244 ****** 15/August/00 1/Dec/00
SEVILLA-HUELVA (I/V)................. 230 ****** 15/August/00 1/Dec/00
XXXXXXX-XXXXXX-SALAMANCA ............ 555 ****** 00/Xxxxxx/00 0/Xxx/00
XXXXXX-XXXXXXX (I/V)................. 118 ****** 00/Xxxxxx/00 0/Xxx/00
XXXXXXXXX-XXXXX-XXXXXX .............. 237 ****** 00/Xxxxxx/00 0/Xxx/00
XXXXXXXX-XXXXXXX (I/V)............... 106 ****** 15/August/00 1/Dec/00
JEREZ- 44 ****** 15/August/00 1/Dec/00
CADIZ................................

------------------------------------------------------------------------------------------------------------------------------------

SUBTOTAL 2 ..... 2.816 ******

---------------
* Omitted and filed separately with the Securities and Exchange Commission
pursuant to a request for confidential treatment.

DEFINITION OF LOOPS AND ROUTES MAKING UP THE FIRST XXXX NETWORK
NETWORK VALUATION. 2000 PRICES. 1 FIBRE OPTIC PAIR

LOOP 3

------------------------------------------------------------------------------------------------------------------------------------
SECTION LENGTH (KM) AMOUNT OF ANNUAL AVAILABILITY DELIVERY OBSERVATIONS
RENTAL (MILLIONS OF PESETAS) DATE DATE
2000 TARIFFS
------------------------------------------------------------------------------------------------------------------------------------

MADRID-XXXXX-XXXXXXXX-PAMPLONA .......... 87 ****** 15/Aug/00 1/Dec/00 MADRID-CASTEJON
CASTEJON-LOGRONO (I/V)................... 152 ****** 15/Aug/00 1/Dec/00 SECTION LOOP 1
PAMPLONA-ALSASUA ........................ 52 ****** 15/Aug/00 1/Dec/00
ALSASUA-X. XXXXXXXXX..................... 174 ****** 15/Aug/00 1/Dec/00
X. XXXXXXXXX-IRUN........................ 17 ****** 15/Aug/00 1/Dec/00
XXXXXXX-XXXXXX-XXXXXXXX-XXXXXXXXXX (I/V). 316 ****** 15/Aug/00 0/Xxx/00
XXXXXXXXXX-XXXXX-XXXXXX ................. 128 ****** 15/Aug/00 1/Dec/00 XXXXX-XXXXXX
SECTION LOOP 2
------------------------------------------------------------------------------------------------------------------------------------

SUBTOTAL 3 ......... 926 ******

---------------
* Omitted and filed separately with the Securities and Exchange Commission
pursuant to a request for confidential treatment.

DEFINITION OF LOOPS AND ROUTES MAKING UP THE FIRST XXXX NETWORK
NETWORK VALUATION. 2000 PRICES. 1 FIBRE OPTIC PAIR

LOOP 4

-----------------------------------------------------------------------------------------------------------------------------------
SECTION LENGTH (KM) AMOUNT OF ANNUAL RENTAL AVAILABILITY DATE DELIVERY DATE OBSERVATIONS
(MILLIONS OF PESETAS)
2000 TARIFFS
-----------------------------------------------------------------------------------------------------------------------------------

MADRID-XXXXXXXXXX-XXXXXXX-BILBAO ... 104 ****** 15/Aug/00 1/Dec/00 MADRID-XXXXXXX
XXXXXX-SANTANDER-XXXXXX-XXXX ........ 516 ****** 15/Aug/00 1/Dec/00 SECTION LOOP 3
XXXX-XXXX-CORUNA..................... 418 ****** 15/Aug/00 1/Dec/00
CORUNA-PONTEVEDRA-VIGO .............. 179 ****** 15/Aug/00 0/Xxx/00
XXXX-XXXXXX-XXXXXX-XXXXXXXXX ........ 447 ****** 15/Aug/00 1/Dec/00 SALAMANCA-MADRID
SALAMANCA-MADRID..................... - - SECTION LOOP 2

-----------------------------------------------------------------------------------------------------------------------------------

SUBTOTAL 4 1.664 ******

TOTAL 7.586 ******

---------------
* Omitted and filed separately with the Securities and Exchange Commission
pursuant to a request for confidential treatment.

ANNEX 1.C

FIBRE OPTIC TRUNK NETWORKS
RENFE PRICES 2000

1) FIBRE OPTIC TRUNK NETWORK

1.1. PRICE FOR GRANT OF USE OF ONE FIBRE OPTIC PAIR.

a) Networks with length of 1,500 km or more.

-------------------------------------------------------------------------------------------
SECTIONS BASIC PRICE
AMOUNT (PESETAS)
PER KM AND YEAR
-------------------------------------------------------------------------------------------

- IRUN-XXXXXX-XXXXXXXX-BARCELONA-PORT BOU ARC................. *********
- MIRANDA-BILBAO.............................................. *********
- REMAINDER OF NETWORK........................................ *********
-------------------------------------------------------------------------------------------

b) Networks of length less than 1,500 km.

There are three tariff levels below this threshold with a
price increase in proportion to the network reduction.

-----------------------------------------------------------------------------
NETWORK LENGTH (KM) INCREASE IN PTS/KM
OVER BASIC PRICE
-----------------------------------------------------------------------------

1000-1500 *********
500-1000 *********
100-500 *********
LESS THAN 100 To be individually studied

-----------------------------------------------------------------------------
* Omitted and filed separately with the Securities and Exchange Commission
pursuant to a request for confidential treatment.

ANNEX 2

PENALTIES

1. PENALTIES FOR FAILURE TO COMPLY WITH AGREED DELIVERY PERIODS.

The geographical scope for the application of any penalties shall be each
of the routes defined in Annex 1. Penalties for failure to deliver the
optical fibre shall thus be applied, as the case may be, in respect of each
of the routes taken separately.

The applicable penalties shall be:

- 1(st) to 2(nd) week of delay: 0 pesetas

- 3(rd) to 4(th) week of delay:
2.5% of the annual rent
for the section
affected per week or
fraction.

- 4(th) and successive weeks
of delay: 5% of the
annual rent for the
section affected per
week or fraction.

The maximum penalty in respect of the foregoing shall not exceed the annual
rent in respect of each route.

2. PENALTIES FOR INTERRUPTION IN SERVICE.

The geographical scope to be taken into account in applying these penalties
shall be each of the Loops described in Annex 1 of the Contract. Two events
can be distinguished in this section:

- Scheduled cuts: Interruptions in service for previously
scheduled work.

- Breakdowns:Lack of availability of the fibre for the transmission of
signals for reasons not due to force majeure or scheduled cuts.

Under this heading, thresholds are established below which penalties shall
not be applied, as follows:

- Scheduled cuts: 1 cut for each 200 km of network and year. The
duration of each cut may not exceed 2.5+1.5 hours.

- Breakdowns: 1 breakdown for each 300 km of network and year.
The duration of each breakdown may not exceed 8+1.5 hours.

Thus, in the case of scheduled cuts falling within the threshold, all hours
which exceed 2.5+1.5 h on respect of each cut will be subject to penalty,
and all hours spent on scheduled cuts which exceed the defined threshold
will be penalised. Likewise, in the case of breakdowns occurring within the
said threshold, all hours exceeding 8+1.5 h in respect of each breakdown
will be subject to penalty, and all hours spent in repairing breakdowns
which occur outside the threshold established will be penalised.

On this basis, penalties applicable for each hour or fraction of an hour subject
to penalty shall be as follows:

2.1 SCHEDULED CUTS

- Hours exceeding 2.5+1.5 in scheduled cuts within the threshold referred to.

2.5+1.5 hours to 8 hours:100% of the hourly cost of renting the Loop
affected for each hour or fraction.

8 hours to 24: 150% of the hourly cost of renting the Loop
affected for each hour or fraction.

- All hours of scheduled cuts subject to penalty (outside the threshold referred
to).

0-X successive hours: 150% of the hourly cost of renting the Loop
affected for each hour or fraction.

2.2 BREAKDOWNS

- Hours exceeding 8+1.5 in breakdowns within the threshold referred to.

8+1.5 to 24 hours: 100% of the hourly cost of renting the Loop
affected for each hour or fraction.

24 and successive hours: 150% of the hourly cost of renting the Loop
affected for each hour or fraction.

- All hours in respect of breakdowns subject to penalty (outside the
threshold referred to).

0 to 8 hours: 50% of the hourly cost of renting of the Loop
affected for each hour or fraction.

8 to 24 hours: 100% of the hourly cost of renting the Loop
affected for each hour or fraction.

24 and successive hours: 150% of the hourly cost of renting the Loop
affected for each hour or fraction.

3. PENALTIES FOR FAILURE TO MAKE THE PAYMENTS STIPULATED.

Delay in making payments shall give rise to interest equivalent to the
3-month MIBOR plus 1.5% on the amount owing. Delay by FirstMark in payment
exceeding three months shall entitle RENFE to terminate the contract and
receive compensation by way of damages of 30% of the remaining amount of
the Contract, as well, clearly, as the amounts due, with the corresponding
interest thereon, or of the corresponding extension.

--------------------------------------------------------------------------------

ANNEX 3

1. 2. INTRODUCTION

This document is the Technical Agreement in respect of `dark fibre' between
RENFE (grantor) and FirstMark (grantee) and identifies the technical and
operational matters which have not been fully covered in the contract. This
document takes in the "Technical Agreement" referred to in the contract.

In the event of inconsistency between the Technical Agreement and the contract,
the contract shall prevail over the Technical Agreement.

The term `dark fibre' refers to a fibre product leased by RENFE, without
terminal equipment nor intermediate repeaters. FirstMark shall connect its own
equipment to the leased fibre.

3 NETWORK DESIGN

3.1 TRANSMISSION REQUIREMENTS

3.1.1 FIBRE SPECIFICATION

The fibre supplied by RENFE to FirstMark shall be connecting fibre with an index
which complies with recommendation G.652 of the International Telecommunications
Union ("UNION INTERNACIONAL DE TELECOMUNICACIONES - UIT").

Additional requirements.

Maximum attenuation coefficient at 1310nm LESS THAN OR EQUAL TO 0.38 dB/km

Maximum attenuation coefficient at 1550nm LESS THAN OR EQUAL TO 0.25 dB/km

RENFE shall ensure that the fibre requirements are maintained. In the event that
the levels do not comply with that agreed, RENFE shall take the necessary steps
to comply with the said requirements.

3.1.2 SPECIFICATION OF METALLIC CABLE ELEMENTS

RENFE warrants that there shall be no metallic elements in the optical cables
used by FirstMark.

3.1.3 FIBRE CONNECTORS

RENFE shall indicate the type and performance of the fibre connectors used for
termination at FirstMark connection points.

3.1.3.1 FOR CABLES INSTALLED AFTER 1997:

The performance of the fibre connectors for connection points and for use in all
new fibre cable systems shall be as follows:

- average insertion loss of 0.3 dB
- maximum insertion loss of 0.6 dB

- return loss better than 35 dB

This complies with European specification I-ETS 300 671 degree of attenuation Q,
degree of return loss T. RENFE shall provide information regarding the
manufacturer and precise model of the connectors to be installed (in the
FirstMark fibres) in order that FirstMark can carry out a detailed power budget
calculation.

THERE ARE NO INTERMEDIATE CONNECTORS IN THE REPEATER STEPS (POINTS OF PRESENCE)
OF THE NETWORK LEASED TO FIRSTMARK (THE FIBRE IS FUSED), EXCEPT IN THE FOLLOWING
LOCATIONS: SAN VICENTE, TORRALBA, LA ENCINA, ALSASUA, CHINCHILLA, VENTA DE
BANOS, MAGAZ, ALJUCEN, GUADIX, ESPELUY.

3.1.3.2 FOR CABLES INSTALLED BEFORE 1997:

The performance of the fibre connectors for the connection points in all the
fibre cable systems already installed is as follows:

- average insertion loss of 0.5 dB
- maximum insertion loss of 0.6 dB
- return loss better than 30 dB

For connection points, connectors are type FC/PC. RENFE will provide information
regarding the manufacturer and precise model of the connectors which are
installed (in the FirstMark fibres) in order than FirstMark can carry out a
detailed power budget calculation.

3.1.4 FIBRE SPLICES

RENFE only utilises fusion splicing. The fusion splicing technology will be
single fibre automatic core alignment fusion splicing.

The fusion splicing performance is as follows:

- average insertion loss of 0.1 dB
- maximum insertion loss of 0.3 dB.

As single fibre automatic core alignment fusion splicing has only been widely
used since 1992, those cable systems constructed prior to that date will contain
splices with poorer performance. Consequently, a second category of splicing
performance will be acceptable for cable systems installed prior to 1992. For
these older cable systems, the fusion splicing performance shall be as follows:

- average insertion loss of 0.2 dB
- maximum insertion loss of 0.5 dB

IN RELATION TO SUB-CLAUSES 2.1.3 AND 2.1.4 OF THIS CLAUSE, RENFE STATES THAT ALL
OF THE CABLES IN THE NETWORK LEASED TO FIRSTMARK HAVE BEEN MANUFACTURED AFTER
1977 EXCEPT FOR THE ATOCHA-GUADALAJARA AND XXXXXXX-XXXXXXX SECTIONS.

2.1.5. ADDITIONAL TRANSMISSION LINK REQUIREMENTS

As well as the fibre, connectors and splicing performance already covered in
section 2, it will be necessary to control other link transmission parameters.

RENFE shall guarantee that, for each fibre pair, the fibres are supplied in
pairs which run together through the same cable elements (conduits) over the
whole of the link. All RENFE maintenance procedures shall include this
requirement except in the exceptional case of provisional fault restoral. This
will ensure a clear understanding regarding availability and enable length
differential to be ensured.

In the event that RENFE wishes to include any additional component in the
FirstMark fibres, e.g. WDMs, for maintenance verification or supervision, the
approval of FirstMark shall be obtained.

2.1.6. MAINTENANCE BUDGET

A maintenance budget is established of 3dB. Maintenance Budget shall mean
transmission degradation during the period of the contract or extensions thereto
- caused by repairs, section changes, etc., carried out on the optical fibre in
each repeater/amplification section. The objective is not to exceed 2 dB.

When a level of 2 dB is reached in a specific section, RENFE shall take the
appropriate action to achieve a maximum degradation value of 1 dB in the section
concerned.

If a FirstMark optical system ceases to function as a result of exceeding the
maintenance budget, RENFE shall in any event then take immediate action to
correct the situation without having to redesign or reconfigure the optical
system.

3.2 ACCEPTANCE TESTS

Acceptance measurements shall be carried out by RENFE personnel in the presence
of FirstMark personnel when the latter considers the same necessary. RENFE
measuring equipment shall be used unless otherwise agreed. Measurement of power
loss and reflectometry are standard methods for optical fibre cable acceptance
tests and are dealt with in the RENFE "Verification and Commissioning of Optical
Networks" ("COMPROBACION Y PUESTA EN SERVICIO DE REDES OPTICAS") manual. These
methods enable all transmission parameters to be verified except for PMD. PMD is
an important parameter for systems of 10Gbit/s plus, and must therefore be
assessed.

The PMD measurement must be less than or equal to 0.5 ps km (-1/2). This is a
standard limit. RENFE shall provide manufacturers' certificates as evidence that
its network complies with this limit. FirstMark reserves the right to measure
the PMD (bearing the costs of its personnel) during the fibre acceptance
process.

3.3 RELIABILITY
RENFE shall provide the following information based on its previous experience:

a) the frequency of damage on routes (per km)
b) damage reestablishment time on routes (average and maximum)
c) frequency of scheduled cuts
d) duration of scheduled cuts (average and maximum)

e) fibre fault rate, excluding damage to cable - e.g. faults caused by
technicians working on access points
f) type of optical plant utilised
g) number of splices on routes
h) geographical route of fibres
i) installation practice (overhead, through conduits, etc.)
j) capacity and type of cable
k) date of manufacture (not purchase) and installation.

The information obtained from a) to g) enables availability figures to be
calculated for specific routes and h) ensures that route separation for the
network can be achieved. The information in i) to k) can be used to assess the
probable rate of intervention faults and the damage rate based on known
performance of the network, thus permitting an estimate of availability to be
made.

RENFE shall comply with a maximum repair time of less then or equal to 8 hours.

For new cable routes, signing of underground routes is desirable by means of
markers and a continuous underground warning mesh.

3.4 CONNECTION OPTION

When leased fibre is used, a passive configuration point shall be the
demarcation point between FirstMark and RENFE. It is absolutely necessary that
ownership of the passive configuration point and responsibility for maintenance
is agreed. There are three potential network positions for the connection
interface between networks. In these situations only the case of RENFE buildings
is considered in which FirstMark utilises space covered in this contract (space
for two standard frames). These are:

A. In the RENFE Telecommunications closet.
B. In a different closet but in the same building as the RENFE
Telecommunications closet
C. In a different building from the building in which the
RENFE Telecommunications closet is housed.

Those cases in which FirstMark leases technical premises from RENFE other
than covered in this contract are not covered.

A.- FIRSTMARK EQUIPMENT IN THE RENFE TELECOMMUNICATIONS CLOSET.

The FirstMark optical fibres shall be carried by RENFE to the termination
premises thereof. The routing of the cables within the closet (between the
termination point and the FirstMark systems) shall be defined by agreement
between RENFE and FirstMark. The optical fibres terminate in the RENFE premises
in a cable termination frame.

CONNECTOR INTERFACE: RENFE shall be responsible for the trunk cable and the
terminal connector. FirstMark shall be responsible for laying its own connection
lines (connectors and cables) from this connection point to its own systems.

Maintenance within the cable distribution termination tray shall be the
responsibility of RENFE.

B.- FIRSTMARK EQUIPMENT IN A CLOSET OTHER THAN THE RENFE TELECOMMUNICATIONS
CLOSET, BUT IN THE SAME BUILDING WHERE THE FIBRE OPTIC CABLE TERMINATES.

The optical fibres shall be carried by RENFE to the termination premises
thereof. The routing of the cables within the building (between the termination
point and the FirstMark systems) shall be defined by agreement between RENFE and
FirstMark. The optical fibres terminate in the premises of RENFE in a cable
termination frame.

CONNECTOR INTERFACE: RENFE shall be responsible for the trunk cable and terminal
connector. FirstMark shall be responsible for laying its own connection lines
(connectors and cables) from this connection point to its own systems.

Maintenance within the cable distribution termination tray shall be the
responsibility of RENFE.

C.- FIRSTMARK EQUIPMENT IN A BUILDING OTHER THAN THE BUILDING HOUSING THE RENFE
TELECOMMUNICATIONS CLOSET.

The optical fibres shall be carried by RENFE to the termination premises
thereof. The routing of the cables between the buildings shall be implemented
using two diverse routes and shall be the responsibility of RENFE.

In this case the cable does not terminate at the RENFE telecommunications closet
but will be extended to the termination point where it will terminate at an
optical distributor.

Maintenance within the cable distribution termination tray shall be the
responsibility of RENFE.

Since all network operators will require access to a given connection point, it
will be of the utmost importance that proper labelling and recording takes place
to prevent accidental circuit interruption. Consequently, RENFE shall produce,
maintain and make available to FirstMark the lists of unions and routing
configuration of the connection point for the fibres leased to FirstMark. These
lists shall be detailed by cable, cable element, splicing tray and fibre.

At connection points, in terms and conditions which it agrees, RENFE shall not
restrict access to the premises by third party network suppliers contracted by
FirstMark for the

connection of other networks or cables not covered by this agreement or, in the
event of agreement between FirstMark and RENFE, the latter shall carry out all
connection and maintenance work and charge FirstMark with the reasonable cost
thereof.

3.5 REQUIREMENTS OF THE PHYSICAL NETWORK

3.5.1 FIBRE SPECIFICATIONS

The proof test requirement under EN 188100 is greater than or equal to an
elongation of 0.7%, but a proof test of 1% is more normal and is advisable for
all cables installed after 1997. Furthermore, it is advisable that the fatigue
resistance parameter ("n") is greater than or equal to 20. RENFE will provide
FirstMark with the value of these parameters provided by the manufacturer.

3.5.2 CABLE SPECIFICATIONS

The relevant specification for the type of cable supplied by RENFE is EN 18700.

RENFE shall provide FirstMark with:

- Specification of optical fibre cables required from
manufacturers.

- The year of installation of the cable sections through which
the leased fibre passes.

- The number of fibres in a cable element.

Knowledge of the age of the cable containing the leased fibres assists in
understanding the performance of both the fibre and the splicing technology
(reference is made to 2.1.1 and 2.1.4).

3.5.3 MECHANICAL SPECIFICATIONS

At passive configuration nodes maintenance technicians require individual access
to the fibres. It is important for service availability that this is achieved
without adversely affecting any other working circuit which passes through the
premises. Consequently, the design of fibre organisation and cable
management/routing must be such that access can be gained and at the same time
ensuring the optical transmission performance of all circuits which are working.

In all splice closures and distributors where routine access is required for
maintenance and operations, RENFE shall use its best efforts to ensure that
management of the FirstMark fibres takes place by handling a single circuit and
that access to each FirstMark fibre takes place in such a way that any handling
of other fibres does not degrade the performance of the FirstMark fibres. This
is the criterion which RENFE shall adopt for all new installations.

3.5.4 PHYSICAL SECURITY

The buildings through which the leased fibre passes must be subject to
restricted access limited solely to authorised personnel. RENFE will lay down
the access criteria.

The buildings provided by RENFE to house FirstMark equipment under this contract
are not equipped with fire, water or entry alarms. FirstMark shall be
responsible for the installation thereof as it considers necessary. RENFE shall
collaborate in full for this purpose.

3.5.5 POWER SUPPLY REQUIREMENTS

In those RENFE premises included in this contract where FirstMark houses
repeater equipment, power supply requirements shall be covered by the RENFE
infrastructure. RENFE shall provide AC power at 220V with a maximum consumption
of 4.4 Kw, without protection from power cuts. The financial and payment terms
shall be agreed between the parties.

In those RENFE premises where FirstMark rents space for equipment, other than
repeater premises, power supply requirements shall be covered by a separate
contract.

3.5.6 CIVIL SPECIFICATIONS

RENFE shall identify those routes which do not have capacity to accommodate
additional cables.

3.6 SAFETY

3.6.1 LASER SAFETY

RENFE enforces a policy in accordance with EN60825-1 standards for working on
live fibre in cables containing laser systems, such that the safety of persons
can be ensured.

3.6.2 TECHNICAL SAFETY

The premises which FirstMark uses to house repeaters and other premises rented
from RENFE shall not be equipped with electrical and lightning protection and
FirstMark shall therefore be responsible for the installation thereof as it
considers necessary. RENFE shall collaborate with it for this purpose.

4. RESOURCES

4.1 EQUIPMENT

All testing equipment shall have calibration certificates and be included within
a maintenance and calibration programme with the equipment manufacturer or
supplier. The type and serial numbers of the equipment used for the acceptance
tests must also be included in the test files in order to monitor the testing
equipment in relation to calibration.

4.2 COMPETENCE OF PERSONNEL

RENFE shall take the appropriate steps to ensure that its personnel are
correctly trained.

RENFE shall ensure that only fully trained personnel work on the fibre network.
In order that FirstMark has confidence in the quality of the RENFE personnel,
FirstMark may when it considers appropriate examine the training programme and
courses in relation to personnel working on the fibre network leased by
FirstMark.

5. CONSTRUCTION

The construction process covers deployment of the whole of the network. For the
trunk network, this consists of the provision of fibre along the railway routes
and conduits in the railway stations as agreed for connectivity with the
FirstMark equipment.

5.1 PROCESS RESPONSIBILITIES

RENFE shall notify FirstMark of completion of construction of the leased element
within the periods set out in the contract terms and conditions covering the
same. Notice of completion of construction shall be accompanied by an invitation
to accept the same. If acceptance takes place successfully, FirstMark shall
furnish its agreement thereto within the period defined in section 4.1.2.
Section measurements shall previously be carried out in accordance with the
provisions of section 4.1.1. It shall be deemed that construction has been duly
carried out in accordance with the contract terms and conditions if acceptance
of the leased element takes place in accordance with the terms and conditions of
the contract. The agreed penalties shall be applied if the contract time limits
are exceeded.

5.1.1 SECTION MEASUREMENT PROCESS.

DEADLINE

At least 8 days prior to commencing the measurement process, FirstMark shall
have received notice of construction of a section accompanied by an invitation
to carry out the

measuring process. Reports shall be delivered to FirstMark after measurements
are completed.

MEASUREMENTS

Acceptance measurements shall be made in the measurement process in accordance
with the RENFE document entitled "Verification and Commissioning of Optical
Networks" ("COMPROBACION Y PUESTA EN SERVICIO DE REDES OPTICAS"). FirstMark
shall thereafter evaluate the reports. Within two working days after receiving
the reports, FirstMark shall confirm acceptance or rejection thereof. If
FirstMark fails to reply, it shall be deemed after 5 working days that
measurements of the section in question have been accepted.

The acceptance tests shall be carried out over 100% of those fibres supplied for
trunk network applications.

REJECTED MEASUREMENTS

If FirstMark rejects the measurements, FirstMark shall provide RENFE with the
reports (or the FirstMark reports if it has carried out its own measurements)
with the measurements as evidence. These reports must demonstrate that the
services agreed in the contract have not been delivered. RENFE shall rectify any
defect within the period up to the delivery date. After rectification work, the
measurement process shall be repeated.

MEASUREMENT ACCEPTED

FirstMark shall confirm acceptance of section measurements within a period of 5
working days.

5.1.2 ROUTE ACCEPTANCE PROCESS

DEADLINE

RENFE shall give formal notice to FirstMark of the date of completion of each
complete route (as defined in the contract), accompanied by a certificate of
delivery/reception. Prior to giving notice of the completion of each complete
route, RENFE shall provide FirstMark with the Technical Certificates of
measurements carried out over all sections making up the route. The date of this
notification of completion shall be within two months from the date of carrying
out measurements of the oldest section belonging to the acceptance route.
FirstMark may request the appropriate authorisation from RENFE to carry out
measurements prior to the delivery date.

SUCCESSFUL ACCEPTANCE

If, within one month after delivery to FirstMark, no errors or inconsistencies
are detected in the measurements and verifications carried out by RENFE over the
route as a whole, the said measurements and verifications shall be taken to be
valid from the date of formal notification to FirstMark and the route shall be
deemed accepted from that date, without prejudice to the provisions of the
following paragraphs:

FirstMark shall within this period return the delivery/reception certificate for
the route duly completed. If, at the end of this period, FirstMark does not
reply, it shall be deemed that the route has been accepted.

FirstMark reserves the right to carry out its own measurements when it considers
necessary during the first 2 months after the date of delivery of the full
route. If any or all of the sections do not comply with the values specified for
transmission requirements (section 2.1) two situations can arise:

1. Minor breaches (those which can be corrected within a maximum period of 3
working days from notification thereof): RENFE undertakes to correct
anomalies by maintenance activities within a maximum period of 3 working
days from notice thereof.

2. Serious breaches (those which require more than 3 working days from
notification to be corrected): The route shall not be deemed to be accepted
for the purposes of payment of the charge for use of the network as a result
of poor network performance, provided FirstMark is not operating the route
in whole or in part. As from notification to RENFE of this situation, RENFE
shall have a period of 2 months to correct all such anomalies and carry out
proof tests. At the end of this period, the contract penalties for delay in
delivery of the route shall be applied, taken from the date of acceptance.

COSTS

FirstMark shall only pay the costs of its own personnel taking part in the
acceptance tests.

5.1.3 MONITORING OF THE CONSTRUCTION PROCESS

In the event that FirstMark wishes to monitor the construction process, RENFE
shall provide the following information:

- Percentage of material supplies completed up to the review date.
- Percentage of civil works carried out up to the review date. Total
- number of kilometres of fibre installed up to the review date.
- Total number of fibre splices carried out up to the review date.
- Kilometres of fibre accepted up to the review date.

The date for carrying out the said reviews shall be agreed between RENFE and
FirstMark after signature of the contract.

5.2 CONSTRUCTION PROCESS CONTACT POINT

All contact shall be made through a single Contact Point which shall be agreed
between RENFE and FirstMark after signature of the contract.

5.3 NOMENCLATURE CONVENTION

RENFE shall produce, maintain and make available a Nomenclature of line
identifiers with RENFE codes.

The line designation coding system must make provision for:

- Single identity code.

- Both parties require a database which must support the line
identification code format.

- A concise definition of terms is necessary (e.g. what is the
definition of a section).

- If necessary, a line designation format which covers the network
technology and route association.

- If necessary, the line designation code to cover the wavelength.

This convention shall be developed between the Network Operation departments of
RENFE and FirstMark after signature of the contract.

6. OPERATIONS

6.1 SINGLE CONTACT POINT FOR OPERATIONS

In order to ensure fluid interaction between the parties, it is important that
all departments involved from the two companies have access at all times to the
same updated operational information. This will prevent misunderstandings and
contradictions. This uniform information state must be achieved between the
parties through formatted messages and defined interfaces. To do so, all
operationally important information shall be exchanged through a single defined
interface. For operational information, the contact point designated in the
contract shall be the interface between the parties. These contact points shall
forward information within their own undertaking. Erroneous information as a
result of crossed lines will thus be excluded.

If there is any deviation from this procedure, it shall be specifically defined.

6.1.1 RENFE CONTACT POINT

RENFE shall define a single contact point which shall be available 24 hours of
the day, 365 days a year, for all leased optical fibre lines. RENFE shall
provide the name, address, telephone and fax numbers.

6.1.2 FIRSTMARK CONTACT POINT

FirstMark shall define a single contact point which shall be available 24 hours
of the day, 365 days a year, for all leased optical fibre lines. FirstMark shall
provide the name, address, telephone and fax numbers.

6.2 MAINTENANCE TESTS

6.2.1 TEST WAVELENGTH

Tests shall be carried out within or above the spectral window of 1550 nm (of
1485 to 1585 nm). This is because the fibre is more sensitive to flection loss
within the spectral window of 1550 nm than within the 1300 nm window.

If RENFE wishes to use maintenance systems on the fibres leased to FirstMark to
be used when the FirstMark system is active or which require additional
components to be added to the transmission path, it shall request permission
from FirstMark and agreement must be reached regarding the conditions for
utilisation of the FirstMark transmission path.

6.2.2 TEST PROCEDURE

Maintenance tests are measurements carried out to ascertain the location and
component which has caused a service interruption. The RENFE maintenance
procedure must enable the location and component causing the fault to be
identified.

6.2.3 LOCATION OF FAULTS THROUGH NETWORK OPERATORS

When a network is constructed using leased fibre, there may be occasions when
the repeater sections consist of fibre of two or more lessors (this particularly
applies to connections at borders). This leads to the question of how to locate
a fault between the networks or more than one lessor. Since the approach to
maintenance of the leased fibre is for the lessor, RENFE, to carry out all
maintenance activities, the lessee faces the problem of not knowing which lessor
to contact first.

In the case of a fault in the fibre, FirstMark shall contact all lessors and
have them check fault correlation at transport level with other fibre circuits
in their cables. In the case of damage to cable, this will likely identify which
of the cables of the lessors is affected, since cable damage events normally
affect almost all, if not all, fibres in the cable. The cost of

checking fault correlation at transport level is considered as included in the
cost of leasing the fibre and no additional payment shall be made to the lessors
for carrying out such checks, even if it is not their fibre which is at fault.
Furthermore, the response time for a request for fault correlation checks at
transport level shall be less than 20 minutes. If the fault correlation checks
do not manage to isolate the fault within a particular lessor, it will be
necessary for one of the lessors to carry out tests.

In the event of a fault in a repeater section which is provided by more than one
lessor, but where at least part is supplied by RENFE, RENFE shall carry out an
OTDR test of the whole of the section and provide the information to FirstMark.
During this process FirstMark shall be responsible for coordination of the
necessary action with the third party lessor and in this manner RENFE shall deal
solely with FirstMark. In the event that the fault is not in the fibre supplied
by RENFE, FirstMark shall pay the expenses incurred by RENFE.

Any other trunk link provided by a third party shall be connected to the RENFE
fibre by means of the appropriate equipment - ADM or repeaters.

6.3 CONFIGURATION

All new requests for additional fibre on existing routes shall be handled as in
the construction process in section 4.

6.4 MAINTENANCE

RENFE shall be responsible for maintenance of the leased element. By definition,
maintenance activities are scheduled work and, as such, any resulting cut can be
forecast. Consequently, prior notice can be given and the cut can be made as
short as possible.

With respect to interruptions in service as a result of scheduled work, RENFE
shall be under the following obligations:

1. Less than one scheduled cut per 200 km of network during one year.

2. Maximum time out of service due to a scheduled cut: 2.5 hours. To
this amount should be added 1.5 hours out of service as a result of
proof tests, which may be distributed over several intervals; these
subsequent proof tests shall be agreed with the Customer.

If these limits are exceeded, the contract penalties shall be applied.

The minimum notice period which RENFE shall give to FirstMark prior to
commencing any maintenance activity shall fall into categories. These categories
are defined in section 5.4.1. The prior notice required for the "At Risk"
category shall be 7 days, and for the "Maintenance Cut", shall be 30 days. The
prior notice for "Re-establishment Cut" shall be 2 hours. Furthermore, RENFE
shall ensure that only one disrupting maintenance activity is carried out ("At
Risk" and "Maintenance cut") per transmission loop at a particular time unless
the maintenance activities are being carried out on a single multiplex link or
unless

FirstMark has given its express permission. The definition of a multiplex link
is a pointto point path between two SDH switching locations.

In all maintenance activities (except "No Risk") RENFE shall notify the
FirstMark contact point immediately prior (30 minutes) to commencing the
scheduled work, and after it has been completed.

It is important that after completion of maintenance activities, network
performance continues to fall within the network design requirements (section
2). In order to ensure this, proof tests must be carried out and the information
passed to FirstMark for acceptance. Measurements must repeat the acceptance
tests summarised in section 2.2, except that the reflectometry measurements
should solely record those events which have been carried out by the maintenance
activity. The attendance of FirstMark shall not be required at proof tests in
respect of maintenance activities. The date and time for proof tests shall be
agreed with FirstMark and shall be carried out within a maximum period of 10
days after the maintenance activity unless as a result of operating requirements
FirstMark postpones the tests to a new date agreed by the parties. Whenever
possible, RENFE shall make an alternative route available to FirstMark. The cut
or cuts for testing shall not contribute to the annual figures for the number of
maintenance cuts but will contribute to the time out of service, which shall be
added to the time out of service resulting from the maintenance activity giving
rise to the proof test. Times out of service may be distributed over several
intervals.

6.4.1 CATEGORIES OF MAINTENANCE ACTIVITY

The maintenance process makes use of classification of maintenance activities
into categories. These categories have their corresponding implications. The
categories are as follows:

"NO RISK"

RENFE maintenance activities which represent little or no risk to the FirstMark
fibres. Work not at fibre level, or access at fibre level through the plant with
fibre management achieved using single circuit management, access at the level
of tray or cable element which do not contain FirstMark fibres. IT IS NOT
NECESSARY for RENFE to notify FirstMark of this activity.

"AT RISK"

Those RENFE maintenance activities which represent an acknowledged risk to the
FirstMark fibres, but which must be completed without interrupting the FirstMark
circuits. Access at fibre level which results in access to fibres contained
within the same cable element as FirstMark fibres, or the same fibre
splicing/organisation tray which contains FirstMark fibres.

RENFE MUST GIVE NOTICE at least 7 days previously to FirstMark of the activity
and of the date and time of the work. The prior notice of these events will
enable FirstMark to verify

the availability of an alternative route and switch the traffic. FirstMark may
request postponement of the activity in the event that an alternative route is
not available at the time of the maintenance event. RENFE shall use its best
efforts to comply with this request unless the scheduled activity is necessary
to repair faults affecting RENFE service or that of another customer.

"MAINTENANCE CUT"

Maintenance activities carried out by RENFE which DO INTERRUPT the FirstMark
circuits (e.g. the replacement of cable sections or optical plant elements).

RENFE MUST GIVE NOTICE at least 30 days previously to FirstMark of the activity,
and the date and time of the work. Prior notice of these events will enable
FirstMark to verify the availability of an alternative route and switch the
traffic. FirstMark may request postponement of the activity if an alternative
route is not available at the time of the maintenance event. RENFE shall comply
with this request unless the scheduled activity is necessary to repair faults
which affect the railway service of RENFE or telecommunications service of
another customer. In any event, and whenever possible, RENFE shall provide an
alternative route and implement the same in conjunction with FirstMark.

Furthermore, RENFE shall use its best efforts to carry out any maintenance
activities which affect the service at times of low priority - e.g. night-time
(between 2 am and 6 am).

Immediately prior (30 minutes) to commencing the "Maintenance Cut" activity,
RENFE shall contact FirstMark and confirm that the activity can be carried out.
At that time, FirstMark shall be entitled to request that work be postponed if
it has good reason for doing so (affecting its service) and RENFE shall comply
with this request unless its own railway service or the telecommunications
service of another customer is affected.

"RE-ESTABLISHMENT CUT"

In the event of partial damage to a fibre cable, it is normally necessary to cut
the remaining fibres which are operating in order to permit re-establishment of
the damaged fibres. If the FirstMark fibres are not affected by the initial
damage event, any subsequent cut shall by definition be a scheduled cut;
nevertheless the prior notice which RENFE can give will be limited. RENFE,
however, MUST GIVE NOTICE THEREOF at least 2 hours previously. Prior notice of
these events will enable FirstMark to take the appropriate steps to minimise
risks. Whenever possible, RENFE shall provide an alternative route and implement
the same in conjunction with FirstMark.

6.4.2 CONTACT POINTS

All contact shall be made through the single Contact Point defined in section
5.1.

6.4.3 MONITORING OF THE MAINTENANCE PROCESS

In order to monitor the maintenance process, RENFE shall provide the following
data:

- The total number of maintenance events per route in the
category of "At risk" or higher; provided by year and
category.
- The number of proof tests rejected for maintenance events during
this year.
- The number of maintenance events during the said year
which it has not been able to re-establish within the agreed
times.
- The total time for scheduled cuts during the year, given in hours
per fibre loop.

The time scheduling and data format shall be in accordance with the contract
performance review (see section 8).

6.5 REPAIRS

Repair activities are by definition reactive. There are two procedures for
repairs. The first is re-establishment by direct definitive repair. The second
is provisional re-establishment which restores the fibres as quickly as possible
before commencing permanent repair through the maintenance process. The time of
cuts under both procedures contributes to fibre non-availability.

Times which contribute to fibre non-availability are the sum of the following
times out of service:

TA- Time out of service from occurrence of the fault until notified.

TB- Time out of service after the fault is notified until it is corrected,
either provisionally or definitively.

TC- Time out of service due to a second fault related to the first fault
occurring at the same place and within a period not exceeding 8 hours
from notification of the first fault.

TD- Time out of service for carrying out the maintenance activity which
corrects the fault on a definitive bases.

TE- Time out of service to carry out proof tests. This time may be
distributed into several intervals.

For the purpose of this Technical Agreement, total non-availability time due to
a repair event shall be the sum of the following intervals of time out of
service:

for a definitive repair: T = Tb + Tc + Te
for a provisional repair: T = Tb + Tc + Td + Te

All these service interruptions shall be computed as a single repair event.

6.5.1 PROCESS RESPONSIBILITIES

With respect to service interruptions due to repairs, RENFE shall be under the
following commitments:

1. Less than one cut per breakdown per 300 km of network during one
year.

2. Maximum time out of service due to repair cuts: 8 hours. To this
amount should be added 1.5 hours of time out of service due to the
proof tests which may be carried out immediately in one transmission
direction. The proof tests in the other direction may be completed
subsequently on a date to be determined by mutual agreement between the
parties.

If these limits are exceeded, the contractual penalties shall be applied.

After a cut, RENFE shall use its best efforts to restore the service in the
shortest possible time, even though there is a risk that other cuts may be
caused accidentally during the repair activity itself. Consequently, an
operating window of 8 hours is established after a cut during which, if other
cuts take place, they will be computed as the first cut and the time out of
service shall be taken as the sum of the time out of service of all cuts
occurring in this 8 hour window (Tb + Tc).

In those cases in which the provisional repair approach is utilised, the
subsequent definitive repair must be completed through the maintenance process
as described in section 5.4 within a maximum period of 30 days after rectifying
the initial fault. In this case, maintenance activity to correct the fault on a
definitive basis shall not be taken into account in the statistics for the
number of cuts for maintenance, and time out of service due to this maintenance
activity (including proofing times) shall be added to the time out of service
for the repair event which gave rise to it.

As in the case of maintenance activities, it is important that after completing
the repair activity, network performance continues within the network design
requirements (section 2). To ensure this, proof tests must be carried out and
the data passed to FirstMark for its acceptance. Measurements must repeat the
acceptance tests summarised in section 2.2 except that the reflectometry
measurements should record only those event which have been carried out by the
repair activity. The attendance of FirstMark at the acceptance tests for repair
activities shall not be required. The date and time for acceptance tests shall
be agreed with FirstMark and carried out within a period of 10 days after the
repair activity; unless, as a result of operating requirements, FirstMark
postpones the tests until a new date agreed by the parties. Whenever possible,
RENFE shall provide FirstMark with an alternative route. The cut for tests shall
not contribute to the annual figures for the number of repair cuts but shall
contribute the time out of service which shall be added to the time of the
repair activity giving rise to such proof tests.

Faults in the fibre may be identified by the transmission systems of any of the
parties using the cable or by RENFE technicians working on the network.
Consequently, faults in the fibre may be identified either by FirstMark or by
RENFE. The two following sections, 5.5.2 and 5.5.3, summarise the procedure for
rectifying faults in relation to fibre faults identified by each party
respectively.

6.5.2 FIRSTMARK IDENTIFIES A FAULT IN THE LEASED ELEMENT

a. Identification of the fault by FirstMark.

b. The fault is reported to RENFE by fax or telephone, providing the
following information:
- Date and time when the fault occurred.
- Any additional information for the purpose of rectifying the fault.
- Line code for the defective optical fibre pair. If possible, the
individual fibre affected should be indicated.
- Identification of the repeater section (if known).

c. Confirmation from RENFE of having received the notification.
RENFE confirms that it has received the fault report by telephone or
fax and provides the following information:
- Name of operator responsible.
- Incident code.

d. First interim response.
RENFE provides FirstMark with the following information within a
maximum response time of 120 minutes:
- Type of fault.
- Cause [assumed] of the fault.
- Duration [estimated] of the fault.

e. Rectification of the fault.
The fault is rectified in accordance with the RENFE specifications and
provisions. If necessary, FirstMark may provide support for
rectification of the fault.

f. Interim report.
Based on the fault rectification state, FirstMark will receive a report
by telephone of progress as fresh news appears. If it is ascertained
that the maximum repair time or estimated duration of the fault
indicated in the fault report is exceeded, the interim report shall be
sent by fax. The content of the fax shall be identical to the content
of the fault report. The following supplementary matters shall be
added:

- Explanation of reasons for the delay.
- Estimated duration of the delay.

g. Fault rectification report
After the fault is rectified, notice will immediately be given by
telephone to FirstMark, followed by the corresponding report by fax.
The content of the fax shall be identical to the content of the fault
report and contain the following additional matters:
- End of fault: date/time.

- Confirmed cause of the fault.
- Work carried out.
- Indication whether the fault was rectified by provisional
re-establishment and that maintenance activity is therefore required to
restore the cable section to its state prior to the damage.

h. Confirmation.
FirstMark verifies that the fault has been finally rectified and
confirms the rectification report or, if necessary, indicates the
defects which still remain. If there are no defects, confirmation of
rectification of the fault by RENFE (the date indicated by the fax)
shall be deemed to be the definitive end of the fault. In this case,
the fault duration shall be taken as the time between: the date and
time indicated in the notification fax, and the date and time indicated
in the fault rectification confirmation fax.

6.5.3 RENFE IDENTIFIES A FAULT IN THE LEASED ELEMENT

a. Identification by RENFE of the fault.

b. FirstMark is informed of the fault within the response time of 30
minutes. RENFE sends the following information to FirstMark by fax:
- Line code for the defective optical fibre pair. If possible, the
individual fibre affected will be indicated.
- Date and time when the fault was detected.
- Type of fault.
- Cause [assumed] of the fault.
- Duration [estimated] of the fault.
- Incident identification code.

c. Confirmation by FirstMark of receipt of the notice from RENFE.
FirstMark confirms that it has received the fault report by telephone
or fax and provides the following information:
- Name of operator responsible.

d. Rectification of the fault.
The fault is rectified in accordance with the RENFE specifications and
provisions. If necessary, FirstMark may provide support in rectifying
the fault.

e. Interim report.
Based on the fault rectification state, FirstMark will receive a report
by telephone on progress as fresh news appears. If it is ascertained
that the maximum repair time or estimated duration of the fault
indicated in the fault report is exceeded, the interim report should be
sent by fax. The content of the fax will be identical to the content of
the fault report and contain the following supplementary matters:
- Explanation of reasons for the delay.

- Estimated duration of the delay.

f. Fault rectification report.
After the fault is rectified, the corresponding report will be sent by
fax to FirstMark. The content of the fax will be identical to the
content of the fault report and contain the following supplementary
matters:
- End of fault: date/time.
- Confirmed cause of the fault.
- Work carried out.
- It will indicate whether the fault was rectified by provisional
re-establishment, and therefore whether maintenance activity is
required to restore the cable section to its state prior to the damage.

g. Confirmation.
FirstMark will verify that the fault has been finally rectified and
confirm the rectification report or, if necessary, indicate the defects
that remain. If there are no defects the fault rectification
confirmation from RENFE (the date indicated by the fax) will be
considered as the definitive end of the fault. In this case, the
duration of the fault will be taken as the time between: the date and
time indicated in the notification fax, and the date and time indicated
in the fault rectification confirmation fax.

6.5.4 ESCALATION PROCESS

The escalation procedure will be implemented jointly by the Network Operation
departments of both parties (RENFE and FirstMark) after signature of the
contract.

6.5.5 CONTACT POINTS

All contact shall be through the single Contact Point defined in section 5.1.

6.5.6 MONITORING OF THE REPAIR PROCESS

In order to monitor the repair process, RENFE shall provide the following data:

- The total number of repair events per route during the year
which affect FirstMark fibres.
- Details of the number of faults per repeater section.
- The total number of proof tests rejected for repair events
during the year.
- The number of repair events during the year for which
re-establishment has not
taken place within the agreed times.
- The total time of cuts as a result of breakdowns during the
year, given in hours per route.

6.5.7 LANGUAGE

All communications between the parties shall be in Spanish.

7. OBLIGATIONS ON TERMINATION OF THE CONTRACT

At the end of the fibre lease there will be connection cables which terminate
within the premises used by FirstMark. At the end of fibre leasing, it will be
necessary to remove them or for the owner of the premises to dispose of them.

FirstMark shall be responsible for removing its own equipment and cables and
those installed by third parties contracted by it within a maximum period of 4
months. In the event that they are not removed within this period, RENFE may
dispose of them. FirstMark shall be liable for any claims resulting from removal
of equipment and cable by RENFE brought by third parties contracted by
FirstMark. FirstMark shall use its best efforts to endeavour to shorten this
time and comply with RENFE requests to clear specific spaces.

8. DOCUMENTATION AND ARCHIVES

RENFE and FirstMark shall jointly define, after signature of the contract, the
documentation which must be maintained and its format, and by whom, arising out
of this contract.

Section 7.1 contains a list for guidance (non-exhaustive) of the documents which
may be required.

8.1 SUMMARY OF THE DOCUMENTS AND ARCHIVES

- Testing Archive
- Installation Archives
- Routing Archives
- Capacity Archives
- Traffic Archives
- Configuration
- Technical Specifications
- Location Archives
- Maps
- Control of Changes
- Standards
- Disaster Process
- Process Documents

9. COMMERCIAL MATTERS

RENFE and FirstMark shall notify each other as soon as possible of any imminent
breach of the terms of the contract.

Confidentiality of information is critical to both parties (RENFE and
FirstMark). This is particularly applicable to information regarding customers.
The contract must ensure that information relating to FirstMark customer
connection and any other information which RENFE acquires as a result of this
contractual relationship is not available to third parties outside RENFE, nor to
other departments of RENFE which are unconnected with the subject matter of this
contract nor, in particular, to any other customer of RENFE who will often be in
direct competition with FirstMark. Furthermore, FirstMark undertakes to keep
information relating to this contract in confidence. In particular, the
financial aspects of the contract; network topology, capacity and locations;
statistical data, standards and processes, and other information which FirstMark
acquires as a result of this contractual relationship.

It is good practice to review the performance of suppliers in relation to the
terms and conditions of their contracts. In order to facilitate the review
process, a standard format must be agreed for the contract performance review
report and the review period must be agreed, which shall normally be annually.
In the event of performance inferior to that indicated in the contract,
FirstMark reserves the right to require more frequent reviews. All costs of
RENFE arising as a result of compiling and providing review reports shall be for
account of RENFE.

RENFE undertakes to provide a review report on performance of the contract on a
fixed date and in a particular format. The periods and format shall be agreed
between the parties after signature of the contract.

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ANNEX 4

VERIFICATION AND COMMISSIONING OF
OPTICAL NETWORKS

--------------------------------------------

2. INTRODUCTION

This document establishes the most important technical parameters of the
RENFE optical fibres along with the tests and measurement methods necessary
to verify them.

3. RESULTS OF TESTS PROVIDED BY RENFE

RENFE shall provide transmission measurements - for the optical fibres
which it leases - as follows:

1. Results of OTDR tests in accordance with the indications set out in
sections 3 and 4.

2. Power loss (under the same conditions as the previous item).

3. Results of cable manufacturers' tests (attenuation/km, CD, PDM) as
indicated in section 5.4.

4. The types of connectors used, indicating attenuation, return loss,
number of connectors and location.

5. Date of cable installation.

6. RENFE cannot measure the PDM value. Nevertheless, it will provide the
measurements made by the manufacturer of the fibre and provide the
necessary facilities for the customer to carry out measurements of
this parameter at points where it considers the same desirable.

4. TESTS TO BE CARRIED OUT

Three classes of tests shall be carried out:

1. OTDR:

- In order to determine:

- total attenuation of the link
- any particular points on the line
- return loss and attenuation in all connectors
- attenuation loss of splices

- Specifications:

- wavelength: 1550 nm. (1)
- reflectance threshold: - 50 dB (2)

(1) In the event that any non-standard values appear, measurements shall also
be made at 1310 nm to compare results. If the difference between the two
measurements exceeds 0.1 dB, RENFE shall take the appropriate action to
correct the anomaly.

(2) Threshold fixed in the equipment as from which existing events are
included.

- Refraction coefficient:

- the refraction coefficient provided by the manufacturer
shall be provided if there is a single type of fibre in the
link.

- the required refraction coefficient shall be 1.467 if it is
not initially known or if the link consists of different
types of fibre.

- Pulse duration: The minimum pulse must be used which permits the
whole distance to be seen. This pulse width shall be different
for different link distances. The exact value of the pulse used
shall be determined by the operator of the OTDR. The following
pulse duration figures can be considered indicative:

> 0-40 km impulse duration = 2.5 microseconds
> 40-80 km impulse duration = 5 microseconds
> over 80 km impulse duration = 10 microseconds

2. Power loss:

- In order to determine:

- total attenuation of the link, in exact terms

- Specifications:

- wavelength: 1550 nm for all links
- wavelength: 1310 nm for distances of less than 30 km

3. PMD (Optional)

- In order to determine:

- dispersion of the link in polarisation mode, in exact terms

- Specifications:

- distance (see the OTDR results)

RENFE shall provide the measurements of this parameter made by the
manufacturer of the optical fibre. RENFE shall facilitate these tests
by FIRST XXXX personnel if the latter so wishes.

4. TESTING PROCEDURES

This section defines the procedures for OTDR, return loss and PMD tests (if
carried out).

For the purposes of clarity, the two ends of the link are designated in
this document as:

- Point A
- Point B

It shall be expressly indicated (when the results of the measurements are
provided) which are points A and B.

These points are usually the terminal connectors of the link. These
connectors are normally installed in RENFE premises.

If the fibre link in question does not terminate at a connector, a
connector will be spliced in order to carry out the tests as indicated in
this document.

4.1. OTDR Test

The OTDR equipment must be capable of measuring differences 50 km
greater than the length of the link.

An OTDR test shall be carried out in two directions:

- from Point A to Point B
- from Point B to Point A

The manner of carrying out the OTDR test is specified in the following
sections:

4.1.1. From Point A to Point B

-------------------------------------------------------------------------------------------------------------------------
Operation - The OTDR is connected to connector C1 at
1 Point A. Two measurements are taken:

Point A

- events in link 1
- characteristics of the fibre in
link 1

Fibre 1 Fibre 2

Point B

-------------------------------------------------------------------------------------------------------------------------
Operation Point A - As in the previous case
2

Fibre 1 Fibre 2

Point B

-------------------------------------------------------------------------------------------------------------------------

4.1.2. From Point B to Point A

-------------------------------------------------------------------------------------------------------------------------
Operation

1 - As in the previous case

Point A

Fibre 1 Fibre 2

Point B

-------------------------------------------------------------------------------------------------------------------------
Operation - As in the previous case
2 Point A

Fibre 1 Fibre 2

--------
OTDR
--------

Point B

-------------------------------------------------------------------------------------------------------------------------

Note 1. A loop system should be used (reflectometric extender) between the
OTDR and the point of measurement.

A loop should also be connected to the terminal point in order to
guarantee accuracy of the measurements at the terminal connectors.

These loops should be of a length necessary to guarantee the accuracy
of the OTDR measurements from the point of measurement.

4.1.3. Validation of OTDR results

During the tests, the results of the OTDR test must be compared with
the specifications in section 7.

If the results are not satisfactory, the necessary corrections shall
be made and the measurements repeated, always in accordance with the
indications of this document. If, after several measurements, the
fibre still does not comply with the specifications, the corresponding
action shall be taken to solve the problem (cleaning connectors,
repetition of fusing, etc.) and new measurements taken.

4.2. Measurement of power loss

In order to determine the power loss, the following three steps shall
be taken:

1. Reference power prior to measurement.
2. Measurement from Point A to Point B.
3. Reference power after measurement.

These steps are specified in the following sections:

4.2.1. Reference power prior to measurement

The first step consists of determining the reference power
transmitted and received by the measurement equipment at one end
of the link, as indicated in this diagram:

Point A

Point A
-------------
Reciever 1 2 1
------------- -------------
Transmitter ----------------------------------------- Reciever
------------- -------------

1 Connection run
Adaptor (1)
2
+ Connectors (2)

This measurement is made before and after measurement of the
fibre.

4.2.2. Measurement from Point A to Point B

This measurement determines the link loss from A to B. The
results of this measurement must be immediately compared with the
results of OTDR attenuation.

Nevertheless, the loss of one connector (e.g. 0.5 dB) must be
added to the attenuation measured, since the same has been
included in calibration.

The measurement shall be implemented in accordance with the
following diagram:

------------>
Point A

2 Fibre n 2
------------- 1 1 -------------
Transmitter ----------------------------------------- Reciever
------------- -------------

1 C
Connection run
2 A
Adaptor (1) + Connectors (2)
3 F
Fibre to be measured

4.2.3. Reference power after the measurements

Once all the fibres have been measured, the reference power of
the measuring equipment must again be measured in accordance with
the specifications defined previously. If the difference between
this measurement and the initial measurement is greater than 0.4
dB, the Customer shall be notified and the same shall decide
whether or not to accept the measurements.

Implementation is defined in the following diagram:

Point A

Point A
-------------
Reciever 1 2 1
------------- -------------
Transmitter ----------------------------------------- Reciever
------------- -------------

1
Connection run

3 Adaptor (1)
+ Connectors (2)

4.3. Measurement of the PMD value (optional)

In the event that FIRST XXXX so requests, and at its own cost,
polarisation mode dispersion tests (PMD) shall be carried out in
respect of all fibres in one direction only, with the power source at
one end and the PMD analysed at the other.

After the measurements, the PMD analyser will give the following
results per link:

- Total PMD value in ps
- PMD value in ps / km

It is not necessary to repeat these measurements in the other
direction.

5. PRESENTATION OF THE RESULTS

The results of the measurements shall be presented to FIRST XXXX by the
latest 7 working days after completing the tests for the power loss
measurements and within 15 working days of completing the tests for other
measurements.

Each measurement report must always include:

- the name of the person who carried out the tests.
- brand, type and serial number of the measuring equipment used, date
and calibration certificate issued by the manufacturer.

- Accurate identification of the FIRST XXXX optical fibres in each
optical distributor on the network layout.

RENFE shall provide FIRST XXXX with the following measurement details:

5.1. OTDR

The optical time domain reflectometer (OTDR) results shall be notified
in the following manner:

- From A to B
- From B to A

Event table for each link. The event table provided by the OTDR
measuring equipment shall be submitted, which shall provide the
following data:

- Event type
- Attenuation
- Return loss or reflectance (as the case may be)
- Location (km)
- Pulse duration used. If this information is not shown in the
event table, it must be included in the corresponding chart.

For:

- From A to B
- From B to A
- Average.

- A comparison of OTDR recorded events and the physical arrangement
of the table (ODF, splice closures). This comparison will enable
any cable installation problems to be established.

- An explanation of all events outside specifications.

- A diskette with the above mentioned records, RENFE shall provide
these records if possible on standard OTDR BELLCORE GR196-CORE
Issue 1.

5.2. Power loss

The power loss results shall be reported in the following manner:

- Reference results:

- Reference power (before and after the measurements)
- Variation in reference power (before and after the
measurements)
- Attenuation in dB between connectors located in the RENFE
equipment room.

5.3. PMD (Optional)

The results of polarisation mode dispersion (PMD) shall be presented
in the following manner:

- Total PMD per fibre, in picoseconds (ps).
- PMD per fibre in picoseconds per square root of kilometres
(ps /(Square Root)km)

(RENFE shall provide a copy of the manufacturer's results regarding
the same. RENFE shall facilitate these tests by FIRST XXXX personnel
if so required).

5.4. Manufacturer's tests

RENFE shall provide FIRST XXXX with the results of the following tests
carried out by the cable manufacturer:

- Optical properties

Attenuation:

- Maximum value between 1,285 and 1,330 nm. (spectral attenuation
curve of a sample of the optical fibre used).
- Maximum value of 1,550 nm.
- Attenuation uniformity (predetermined premises).

Chromatic dispersion:

- Between 1,285 and 1,330 nm. (the particular values provided by
the manufacturer should be provided).

- At 1,550 nm.
- Dispersion in polarisation mode.

6. ABBREVIATIONS

CD Chromatic dispersion

ODF Optical Distribution Frame

OTDR Optical Time Domain Reflectometer

PMD Polarisation Mode Dispersion

7. SPECIFICATIONS OF RENFE OPTICAL FIBRE

------------------------------------------------------------------------------------------------------------------------

TYPE AND STRUCTURE

Mono-mode, in accordance with CCITT G 652 specifications.

The fibres consist of an adulterated silica core covered by a silica shield and a two-layer coating of ultraviolet-hardened
acrylate.

------------------------------------------------------------------------------------------------------------------------

GEOMETRIC PROPERTIES

Field diameter at 1310 nm (micrometers) [9-10]+/- 10%
Shield diameter (micrometers) 125+/-3
Coating diameter ((micrometers) 245+/-10
Field excentricity (%) LESS THAN OR EQUAL TO 6
Shield excentricity (%) LESS THAN OR EQUAL TO 2
Core/shield concentricity error ((micrometers) LESS THAN OR EQUAL TO 1
Shield/coating concentricity error ((micrometers) LESS THAN OR EQUAL TO 15

------------------------------------------------------------------------------------------------------------------------

OPTICAL PROPERTIES

Shear wavelength (fibre in cable) (nm) (lambda) cc LESS THAN OR EQUAL TO 1280

Attenuation:
Maximum value between 1285 and 1330 nm (dB/km) 0.38
Maximum value at 1550 nm (dB/km) 0.25

Uniformity of attenuation (predetermined premises) (dB) LESS THAN OR EQUAL TO 0.1

Chromatic dispersion:
Between 1285 and 1330 nm (ps/xx.xx) LESS THAN OR EQUAL TO 3
At 1550 nm (ps/xx.xx) LESS THAN OR EQUAL TO 20

Dispersion in polarisation mode: (ps/(Square Root) km) LESS THAN OR EQUAL TO 0.5

------------------------------------------------------------------------------------------------------------------------

MECHANICAL PROPERTIES

Transmission tests (%) LESS THAN OR EQUAL TO 1
(minimum duration 1s)
Flexion test
Additional loss at 1550 nm (dB) LESS THAN OR EQUAL TO 0,1
(100 turns on a 75 mm diameter mandrel)
------------------------------------------------------------------------------------------------------------------------

8. SUMMARY OF SPECIFICATIONS

- Standard mono-mode

Splice value = (Splicing measurement from A to B + splicing measurement
from B to A) /2

- Average maximum value of splices LESS THAN 0.1 (*)
- Individual maximum value of splice LESS THAN 0.5 dB
- Maximum unit attenuation ODF/S connector (1 connector+1 adaptor+1
connector)=0.5 dB at 1,550 nm.
- Connector return loss, better than 30 dB at 1,550 nm.
- Maximum dispersion value in polarisation mode = 0.5 ps/(Square Root)km
a 1,550 nm.
- RENFE shall procure that no optical fibre distributors are installed
in the optical fibres of FIRST XXXX on the sections between two FIRST
XXXX repeaters.

8. RESULTS TO BE SUBMITTED

8.1. Information regarding equipment

RENFE shall provide FIRST XXXX with the following data for each
measurement:

Name of person carrying out the measurements.

Date of measurement.

Brand of measurement equipment.

Type of measurement equipment.

Serial number of measurement equipment.

Calibration date and certificate number.

Links and fibres measured with this equipment.

8.2. OTDR event table

The format for presenting results shall be as indicated in Annex A.

8.3. Power loss

The format for presenting the results shall be as indicated in Annex
A.

(*) The average is calculated taking into account all splices in a
repeater span. For example, if there are ten splices in a span,
total attenuation may not exceed 1dB.

ANNEX A

RENFE INFRASTRUCTURE
MAINTENANCE TELECOMMUNICATIONS

OPTICAL POWER LOSS MEASUREMENTS

Details of Link

-----------------------------------------------------------------------------------------------------
Station A: Fibre length

Station B: Type of Cable
-----------------------------------------------------------------------------------------------------

General Data Date:

-----------------------------------------------------------------------------------------------------
First and last names: JTMI/Undertaking
-----------------------------------------------------------------------------------------------------
Initial ref. reading (dB) Difference (dB)
-----------------------------------------
Final ref. reading (dB) Wavelength
-----------------------------------------------------------------------------------------------------
Equipment Brand and Model Serial No. Calibration ref. and Date
-----------------------------------------------------------------------------------------------------
Light Source

Power measurer**
-----------------------------------------------------------------------------------------------------

------------------------------------------ ----------------------------------------------
Fibre Reading Attenuation Fibre Reading Attenuation
------------------------------------------ ----------------------------------------------

------------------------------------------ ----------------------------------------------

Attenuation (dB) = Reading - Inital reference reading - 0.5

RENFE INFRASTRUCTURE
MAINTENANCE MEASUREMENTS OF OPTICAL FIBRE SPLICES

Sheet ... of ...

------------------------------------------------------------------------------------------------------------------------------
Station A: Station B: Fibre Length: Type of Cable:
------------------------------------------------------------------------------------------------------------------------------
First and last names: JTMI/Undertaking: Date:
------------------------------------------------------------------------------------------------------------------------------
OTDR Make and Model Serial no. Calibration ref. and date Wavelength:
------------------------------------------------------------------------------------------------------------------------------

------------------------------------------------------------------------------------------------------------------------------
Fibre N DEG. Length N DEG. Length N DEG. Length
------------------------------------------------------------------------------------------
N DEG. A - B B - A Average A - B B - A Average A - B B - A Average
--------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------

-------------------------------------------------------------------------- ------------
Fibre N DEG. Length N DEG. Length Average
------------------------------------------------------------ Value
N DEG. A - B B - A Average A - B B - A Average ------------
-------------------------------------------------------------------------- ------------
-------------------------------------------------------------------------- ------------
-------------------------------------------------------------------------- ------------
-------------------------------------------------------------------------- ------------
--------------------------------------------------------------------------

ANNEX 5

DELIVERY - ACCEPTANCE CERTIFICATE

Pursuant to clause 4.1.2. of the Technical Annex of the Contract of 1 August /00
between FIRSTMARK and RENFE, RENFE hereby delivers to FIRSTMARK the fibre optic
network -one optical fibre pair - over the following route: _______________.

Madrid, __________________________

DELIVERY BY RENFE

Mr. ____________________________

ACCEPTANCE BY FIRSTMARK,

Mr. ________________________

ANNEX 6

ANNEX 6
CONFIDENTIALITY UNDERTAKING

(To be addressed by the party concerned to the other, as appropriate).

In........, the............of ............ , 2000

Dear Sir,

....... has stated its interest in examining the viability of a possible
securitisation operation in respect of the credit rights deriving from the
contract for the use and maintenance of an optical fibre Network entered into
between Red Nacional de los Ferrocarriles Espanoles (RENFE) and FirstMark
Communications Europe, S.A. (FirstMark), hereinafter the "Operation".

In order that ........ can act as financial adviser to ..................... in
the design of the Operation, ............. has agreed to provide to ..........
certain verbal and written information relating to the Operation as well as the
contracts entered into. The information provided is hereinafter referred to as
the "Information".

In relation to the Operation, ....................., states that:

1. It undertakes to maintain the Information in confidence and not to transmit
the same in whole or in part at any time or in any manner to any individual
or legal entity except in the exceptional circumstances expressly provided
in this document and when the Information is communicated to
administrative, supervisory or Stock Exchange authorities.

2. ....... authorises .......... to provide the Information to third parties
when necessary to carry out its study. In this event, it shall enter into
the corresponding confidentiality commitment with the said third party in
identical terms to those set out in this document and forward a copy
thereof to FirstMark/RENFE (as the case may be).

3. ....... undertakes to use the Information provided solely and exclusively
for the purposes of examining the viability and, as the case may be,
designing the Operation, and may not otherwise use the same to the
prejudice of FirstMark/RENFE (as the case may be).

4. The provisions of this document regarding the information shall not extend
to those parts of the Information which are or become public knowledge or
are made public other than by breach of ..................., which is
already in its possession, which has been independently obtained, or has
been obtained from a third party not subject to a confidentiality
obligation.

5. This commitment shall be enforceable and binding on ..........., its
subsidiaries and associates. The obligations set out in this document shall
remain in force whilst relations are maintained between the parties and for
one year as from the date of termination thereof.

6. ............ hereby undertakes to indemnify FirstMark/RENFE (as the case
may be) against loss or damage which may be caused to it by breach of the
terms of this confidentiality undertaking.

7. The parties expressly waive any legal jurisdiction and agree to submit any
dispute, matter or incident which may arise between them in relation to
this Contract to arbitration. The said arbitration shall be at law and the
administration thereof entrusted to the Civil and Mercantile Court of
Arbitration ("Corte Civil y Mercantil de Arbitraje - CIMA") whose bylaws
and procedural regulations are known to the signatories to this document.
Hearing of and decisions regarding the matters in dispute shall be carried
out by a single arbitrator appointed from members of the Civil and
Mercantile Court of Arbitration by agreement of the parties when the
dispute arises or, if not so agreed, by the Chairman of the Court, in
accordance with its bylaws, which the parties state they are also familiar
with. It shall be deemed that agreement is not reached if, within fifteen
calendar days from a request from one party to the other party or parties,
no affirmative answer is received from them all. The parties expressly
record their commitment to comply with any arbitration award issued.

Yours faithfully,

----------------------

..............................(name)
..............................(name of the company)
..............................(position in the undertaking)

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