<PAGE>
                                                                     EXHIBIT 4.3


Sify Limited                                    ASSOCIATE STOCK OPTION PLAN 2002
4 Apr 2003


1.0 INTRODUCTION:

1.1    Sify has formulated a series of Associate Stock Option Plans (ASOP) to
       incentivise and reward associates for contributing to the growth of Sify.

1.2    ASOP 2002 is the latest in the series of these ASOPs. The members of the
       Company approved the allocation of a further 633,000 shares on 09
       December, 2002 to the pool of shares available for issue as stock options
       to associates.


2.0 SCHEME OVERVIEW:

2.1    Under ASOP 2002, Sify's Associates (full time or part time employees and
       directors) would be granted options for a fee which would give them the
       right to buy Sify's ADRs (listed in the Nasdaq National Market in USA) or
       Sify's equity shares as indicated in the letter of grant to them at an
       exercise price. The difference between the market price of these ADRs or
       Equity shares and the exercise price would be the gain to the Associate.
       The options are exercisable after a vesting date but before the expiry
       date. Vesting is slated to happen over a three year period. Expiry occurs
       one month after the associate ceases to in the employment of Sify or its
       subsidiaries.

2.2    As the market price of Sify's ADRs (or in some cases Equity shares) go
       up, the benefit to the Associate goes up. The Associate is incentivised
       to:

       2.2.1  Stay with Sify until vesting and after vesting until the option
              value grows to an attractive level and

       2.2.2  Work (with a high degree of goal congruence) in the interest of
              Sify shareholder in building a sustainable value and growth
              momentum into Sify's ADRs and equity shares.


3.0 ADMINISTRATION:

3.1    Shareholders of Sify have approved the allocation of 633,000 shares to be
       added to the pool of shares to be made available for ASOP schemes on 09
       December, 2002. Shareholders have also empowered the Board of Directors
       to formulate ASOP schemes from time to time to grant stock options and
       when exercised issue ADRs/Equity shares. Shareholders have also
       recognised that these stock options would apply to Principal Officers
       including the Chief Executive Officer, the Chief Operating Officer and
       the Chief Financial Officer and Directors.

3.2    The Board of Directors (Sify Board) have constituted the Compensation
       Committee (currently made up of three directors nominated by Sify Board)
       to formulate ASOP schemes, formulate policies for administration of the
       schemes, and actually administer the scheme by granting options,
       recognize exercises, issue ADRs and shares on exercise, collect exercise
       price and where necessary facilitate sale.

3.3    The Compensation committee of the Board of Directors (Compensation
       Committee) administers the ASOP schemes of Sify. ASOP 2002 will also be
       administered by the Compensation Committee. The Compensation Committee
       will have the authority and responsibility to:

       3.3.1  Formulate ASOP schemes from time to time

       3.3.2  In formulating the ASOP schemes, decide on:

              3.3.2.1  Eligibility criteria, Selection criteria

              3.3.2.2  Granting policy (including quantity, exercise price, fee)

              3.3.2.3  Vesting policy (vesting schedule, policy relating to
                       death/disability)

              3.3.2.4  Recognition of expires (both lapses and forfeitures) and

              3.3.2.5  Movement of quantity allocated for ASOP from one scheme
                       to another

<PAGE>
Sify Limited                                    ASSOCIATE STOCK OPTION PLAN 2002
4 Apr 2003


       3.3.3  Grant Options to Associates (by issue of Option letters)

       3.3.4  Facilitate exercise of options, issue ADRs/Shares and where
              necessary facilitate sales and

       3.3.5  Liase with and comply with regulators including SEC, SEBI, Income
              tax office, etc.

3.4    In all issues to be decided by the Company relating to ASOP, the decision
       by the Compensation Committee represents decision by the Company and is
       final.


4.0 ADRS/SHARES:

4.1    ASOP 2002 aims to grant options to buy either of the following to
       Associates:

       4.1.1  American Depository Shares/Receipts of Sify (listed in the Nasdaq
              National Market of USA under the ticker "SIFY") or

       4.1.2  Equity shares of Sify (currently not yet listed anywhere in
              India).

4.2    The Option letter (granting the option) would explicitly state what is
       being granted. In the absence of such a clarification, ADRs shall be
       issued on exercise.

4.3    Compensation Committee has the power to grant options for a quantity of
       ADRs/Shares not exceeding the unused quantity available in the pool for
       granting of options (as approved by and added to by members of Sify in a
       general meeting). Compensation Committee specifically has been empowered
       to use ungranted surplus out of earlier allocations to the pool to be
       issued under any ASOP scheme including ASOP 2002.

4.4    In the event of a stock split or a ratio change (between ADRs and equity
       shares), the quantity of stock options and the exercise price shall be
       adjusted for the effect of the stock split or the ratio change so that
       the Associate gets the same proportion of shareholding percentage for the
       same price per percentage as the Associate would have prior to the stock
       split or ratio change.


5.0 ELIGIBILITY TO PARTICIPATE:

5.1    Options could be granted under ASOP 2002 only to Associates. Associates
       are defined to include only the full time or part time employees of Sify
       and its subsidiaries. Associates include Principal officers and directors
       of Sify and its subsidiaries. Subsidiaries, for these purposes, includes
       companies in which Sify has more than 50% of issued shares or more than
       50% voting rights in the Board governing such companies.

5.2    The Compensation Committee shall select from among the Associates a list
       of associates for grant of stock options. The Compensation Committee
       shall decide on the selection criteria which shall include among other
       things the performance track record, performance potential of the
       Associates. The Compensation committee is empowered to include Associates
       on any other criteria and is also empowered to not include any Associate
       without stating any reason. The decision by the Compensation Committee on
       the choice of Associates who shall be granted stock options is final.


6.0 GRANT OF OPTIONS:

6.1    The Compensation Committee shall decide on whether the grant is for ADRs
       or equity shares, the option quantity (number of ADRs or equity shares to
       be granted), the exercise price payable, the vesting schedule and other
       terms and conditions of the grant.

<PAGE>
Sify Limited                                    ASSOCIATE STOCK OPTION PLAN 2002
4 Apr 2003


6.2    The Compensation Committee shall issue to the selected Associates Option
       letters granting options to Associates giving them the right to buy ADRs
       (or if so specified, equity shares) specifying the quantity of stock
       options issued and the exercise price, the vesting schedule and other
       terms and conditions. A copy of the ASOP 2002 scheme shall be attached to
       the Option letter. The Option letter should bear the sequential number of
       the Option letter, the name of the Associate and the reference of the
       Compensation committee meeting by which the option is being granted. The
       Compensation Committee should collect an Option fee of Re.1 per ADR (or
       share) which shall be adjusted against the exercise price payable or
       refunded to Associates if the option is not exercised and the option
       expires.


7.0 EXERCISE PRICE:

7.1    Exercise price refers to the price at which the Associate could buy the
       ADR (or equity share). The currency by which exercise price is payable is
       normally Rupees unless otherwise so specified in the Option letter.
       Exercise price is payable to the Company by a cheque made payable to Sify
       Limited.

7.2    The Compensation Committee shall decide on the exercise price for each
       grant on a case by case basis. The Compensation Committee shall comply
       with the requirements of applicable regulations including SEBI
       guidelines, Company law etc in determining the exercise price.


8.0 VESTING SCHEDULE:

8.1    The stock options granted shall be exercised (converted into an ADR or
       equity share) only after the options vest.

8.2    The Compensation Committee shall decide on the terms of vesting of the
       stock options. The Committee shall vary the vesting schedule for any
       grant yet to be issued under the scheme. However no variation shall
       affect any grant that was already made under a specified vesting term
       unless such a variation is beneficial to the Associate. Unless modified
       later, the options granted shall vest as below:

       One sixth of the option quantity: At the end of one year from the date of
       grant Five sixth of the option quantity: At the end of each quarter
       during the second and third year from the date of the grant in eight
       equal instalments.

8.3    In any case the grants shall vest fully on the occurrence of permanent
       total disability or the death of the Associate.

8.4    In the event of a rights issue or a bonus issue of the ADRs or equity
       shares, the Associate shall be given the choice to deem the stock options
       to have vested and exercise the options and subscribe to the rights issue
       or get the bonus issue. If the Associate chooses to not deem the stock
       option to have vested, the vesting schedule shall remain as per the terms
       of the grant. However, the Associate would not be able to participate in
       the rights issue or be eligible for the bonus issue of ADRs or Equity
       shares.


9.0 EXPIRY:

9.1    Stock options issued to Associates can be exercised only after they vest
       and should be exercised before they expire.

9.2    Options issued under ASOP 2002 expire one month after the Associate
       ceases to be in the employment of Sify or its subsidiaries.

9.3    If the options vested earlier than envisaged due to death or permanent
       total disability of the Associate, the options shall expire within one
       month after such a vesting. The

<PAGE>

Sify Limited                                    ASSOCIATE STOCK OPTION PLAN 2002
4 Apr 2003


       Compensation Committee is empowered to extend the expiry date by not more
       than three months in the case of death or permanent total disability of
       the Associate.

9.4    Associates who do not wish to accept stock option grants shall notify
       Sify in writing. Any option recommended by the Compensation Committee to
       them would not be issued to them.

9.5    Associates who do not wish to continue participating in the ASOP scheme
       after the grant is received shall notify the company in writing. The
       options granted would forfeit after the letter is received by Sify. Sify
       would repay the option fee of Re.1 per ADR if such a fee was already
       collected earlier.


10.0 EXERCISE OF STOCK OPTION AND ISSUE OF ADRS/EQUITY SHARES:

10.1   Associates can exercise stock options any time. However Associates can
       sell the ADRs or shares so issued under the option only during the period
       when insider trading is permitted under the "Insider trading policy" of
       Sify.

10.2   The Insider trading policy of Sify shall be as determined by the Board of
       Directors of Sify from time to time and as administered by the Chief
       Financial Officer of Sify from time to time. Unless there are specific
       price sensitive information within the Company, insider trading is
       typically permitted during the period commencing from "two days after the
       press release announcing quarterly results" and ending with "the last day
       of the second month of each quarter".

10.3   If the Associate is not permitted by law to hold the stock (ADR or equity
       share) and is expected to sell it within reasonable time, then exercise
       of the option itself will be permitted only during the period when
       insider trading is permitted.

10.4   Associates wishing to exercise their options should tender to Sify a copy
       of the option letter and a cheque made payable to Sify Limited for the
       exercise price (less the option fee paid at the time of grant) indicating
       the brokerage account to which ADRs or shares should be credited.

10.5   Associates are entitled to exercise part of the option quantity that has
       vested and carry forward the remainder until the options expire and
       exercise such carried forward quantity any time before expiry subject to
       the foregoing clauses on the time window when insider trading is
       permitted.

10.6   The ADRs or equity shares issued to Associates after the exercise of the
       option shall be their exclusive property free of all charges/liens. The
       ADRs or shares will not be subject to any lock in unless such a lock in
       is applicable by law or is applicable to all shareholders of that kind.
       The ADRs or equity shares so issued shall rank pari passu with existing
       ADRs or shareholders and shall be entitled to pro rated dividend/benefits
       from the date of issue and shall enjoy rights/privileges that other
       shareholders enjoy in terms of voting rights etc.

10.7   Sify shall facilitate the sale of the ADRs and shares issued to
       Associates. Conditions relating to insider trading apply for the timing
       of sale by Associates. The ADRs issued by Sify on exercise of option by
       Associates shall be registered and saleable in the Nasdaq market.

10.8   All taxes that apply to the exercise, sale or realization of proceeds
       from ADRs and equity shares accrue to the Associate.


11.0 TRANSFER, MORTGAGE ETC

11.1   Options granted to Associates are not transferable. Options granted to
       Associates transmit to legal heirs on the death of the Associate. All
       rights and obligations of the Associate under the scheme shall accrue to
       the legal heirs of the Associate in the event of death of the Associate.

<PAGE>
Sify Limited                                    ASSOCIATE STOCK OPTION PLAN 2002
4 Apr 2003


11.2   Stock options granted under the ASOP scheme cannot be pledged, mortgaged,
       hypothecated or be subject in any way to a charge or a lien giving right
       to any party other than the Associate.


12.0 OTHERS:

12.1   The Board of Sify and the Compensation Committee have the rights to
       modify the policies and practices of ASOP 2002. However no such
       modification shall apply to a grant already made if that affects the
       benefit of the grant from the associate's point of view.

12.2   This scheme shall not form part of any contract of employment between
       SIFY and the associate. The rights and obligations of any individual
       under the contract of employment shall not be affected by his
       participation in this scheme or any right which he may have to
       participate in it.

12.3   Nothing in this scheme shall afford any associate any additional right(s)
       as to compensation or damages in consequence of the termination of such
       office or employment for any reason.

12.4   This scheme shall not confer any associate any legal or equitable right
       against Sify either directly or indirectly or give rise to any cause of
       action in law or equity against Sify.

12.5   This scheme is subject to all applicable laws, rules, regulations,
       guidelines and to such approvals from any governmental agencies as may be
       required. In case of any contradiction between the provisions of this
       Scheme and any provisions, rules, regulations, guidelines issued by any
       governmental agencies, the provisions of law shall override the
       provisions of this scheme.

12.6   The associates who are granted warrants ADS / Equity under the scheme
       shall comply with such requirements of law as may be necessary.

12.7   Sify does not guarantee any return on the equity investment made by
       associates as part of the scheme. Any loss due to fluctuations in the
       market price of the equity including the shortfall in the expectations or
       projections and the risks associated with the investment are that of the
       associate alone.