<PAGE>

                                                                     Exhibit 1.1
                                                                     -----------

                               8,000,000 Shares



                           CHORUM TECHNOLOGIES INC.


                                 Common Stock


                            UNDERWRITING AGREEMENT
                            ----------------------


                                                            February ___, 2001



Credit Suisse First Boston Corporation
Banc of America Securities LLC
CIBC World Markets Corp.
Thomas Weisel Partners LLC,
As Representatives of the Several Underwriters,
 c/o Credit Suisse First Boston Corporation,
  Eleven Madison Avenue,
  New York, N.Y. 10010-3629

Dear Sirs:

        1.  Introductory.  Chorum Technologies Inc., a Delaware corporation
("Company"), proposes to issue and sell 8,000,000 shares ("Firm Securities") of
its Common Stock ("Securities") and also proposes to issue and sell to the
Underwriters, at the option of the Underwriters, an aggregate of not more than
1,200,000 additional shares ("Optional Securities") of its Securities as set
forth below. The Firm Securities and the Optional Securities are herein
collectively called the "Offered Securities". As part of the offering
contemplated by this Agreement, Credit Suisse First Boston Corporation (the
"Designated Underwriter") has agreed to reserve out of the Firm Securities
purchased by it under this Agreement, up to 400,000 shares, for sale to the
Company's directors, officers, employees and other parties associated with the
Company (collectively, "Participants"), as set forth in the Prospectus (as
defined herein) under the heading "Underwriting" (the "Directed Share Program").
The Firm Securities to be sold by the Designated Underwriter pursuant to the
Directed Share Program (the "Directed Shares") will be sold by the Designated
Underwriter pursuant to this Agreement at the public offering price. Any
Directed Shares not subscribed for by the end of the business day on which this
Agreement is executed will be offered to the public by the Underwriters as set
forth in the Prospectus. The Company hereby agrees with the several Underwriters
named in Schedule A hereto ("Underwriters") as follows:

        2.  Representations and Warranties of the Company.  The Company
represents and warrants to, and agrees with, the several Underwriters that:

            (a)  A registration statement (No. 333-49010) relating to the
     Offered Securities, including a form of prospectus, has been filed with the
     Securities and Exchange Commission ("Commission")

                                      -1-
<PAGE>

     and either (i) has been declared eff ective under the Securities Act of
     1933 ("Act") and is not proposed to be amended or (ii) is proposed to be
     amended by amendment or post-effective amendment. If such registration
     statement ("initial registration statement") has been declared effective,
     either (i) an additional registration statement ("additional registration
     statement") relating to the Offered Securities may have been filed with the
     Commission pursuant to Rule 462(b) ("Rule 462(b)") under the Act and, if so
     filed, has become effective upon filing pursuant to such Rule and the
     Offered Securities all have been duly registered under the Act pursuant to
     the initial registration statement and, if applicable, the additional
     registration statement or (ii) such an additional registration statement is
     proposed to be filed with the Commission pursuant to Rule 462(b) and will
     become effective upon filing pursuant to such Rule and upon such filing the
     Offered Securities will all have been duly registered under the Act
     pursuant to the initial registration statement and such additional
     registration statement. If the Company does not propose to amend the
     initial registration statement or if an additional registration statement
     has been filed and the Company does not propose to amend it, and if any
     post-effective amendment to either such registration statement has been
     filed with the Commission prior to the execution and delivery of this
     Agreement, the most recent amendment (if any) to each such registration
     statement has been declared effective by the Commission or has become
     effective upon filing pursuant to Rule 462(c) ("Rule 462(c)") under the Act
     or, in the case of the additional registration statement, Rule 462(b). For
     purposes of this Agreement, "Effective Time" with respect to the initial
     registration statement or, if filed prior to the execution and delivery of
     this Agreement, the additional registration statement means (i) if the
     Company has advised the Representatives that it does not propose to amend
     such registration statement, the date and time as of which such
     registration statement, or the most recent post-effective amendment thereto
     (if any) filed prior to the execution and delivery of this Agreement, was
     declared effective by the Commission or has become effective upon filing
     pursuant to Rule 462(c), or (ii) if the Company has advised the
     Representatives that it proposes to file an amendment or post-effective
     amendment to such registration statement, the date and time as of which
     such registration statement, as amended by such amendment or post-effective
     amendment, as the case may be, is declared effective by the Commission. If
     an additional registration statement has not been filed prior to the
     execution and delivery of this Agreement but the Company has advised the
     Representatives that it proposes to file one, "Effective Time" with respect
     to such additional registration statement means the date and time as of
     which such registration statement is filed and becomes effective pursuant
     to Rule 462(b). "Effective Date" with respect to the initial registration
     statement or the additional registration statement (if any) means the date
     of the Effective Time thereof. The initial registration statement, as
     amended at its Effective Time, including all information contained in the
     additional registration statement (if any) and deemed to be a part of the
     initial registration statement as of the Effective Time of the additional
     registration statement pursuant to the General Instructions of the Form on
     which it is filed and including all information (if any) deemed to be a
     part of the initial registration statement as of its Effective Time
     pursuant to Rule 430A(b) ("Rule 430A(b)") under the Act, is hereinafter
     referred to as the "Initial Registration Statement". The additional
     registration statement, as amended at its Effective Time, including the
     contents of the initial registration statement incorporated by reference
     therein and including all information (if any) deemed to be a part of the
     additional registration statement as of its Effective Time pursuant to Rule
     430A(b), is hereinafter referred to as the "Additional Registration
     Statement". The Initial Registration Statement and the Additional
     Registration Statement are herein referred to collectively as the
     "Registration Statements" and individually as a "Registration Statement".
     The form of prospectus relating to the Offered Securities, as first filed
     with the Commission pursuant to and in accordance with Rule 424(b) ("Rule
     424(b)") under the Act or (if no such filing is required) as included in a
     Registration Statement, is hereinafter referred to as the "Prospectus". No
     document has been or will be prepared or distributed in reliance on Rule
     434 under the Act.

                                      -2-
<PAGE>

            (b)  If the Effective Time of the Initial Registration Statement is
     prior to the execution and delivery of this Agreement: (i) on the Effective
     Date of the Initial Registration Statement, the Initial Registration
     Statement conformed in all respects to the requirements of the Act and the
     rules and regulations of the Commission ("Rules and Regulations") and did
     not include any untrue statement of a material fact or omit to state any
     material fact required to be stated therein or necessary to make the
     statements therein not misleading, (ii) on the Effective Date of the
     Additional Registration Statement (if any), each Registration Statement
     conformed, or will conform, in all respects to the requirements of the Act
     and the Rules and Regulations and did not include, or will not include, any
     untrue statement of a material fact and did not omit, or will not omit, to
     state any material fact required to be stated therein or necessary to make
     the statements therein not misleading and (iii) on the date of this
     Agreement, the Initial Registration Statement and, if the Effective Time of
     the Additional Registration Statement is prior to the execution and
     delivery of this Agreement, the Additional Registration Statement each
     conforms, and at the time of filing of the Prospectus pursuant to Rule
     424(b) or (if no such filing is required) at the Effective Date of the
     Additional Registration Statement in which the Prospectus is included, each
     Registration Statement and the Prospectus will conform, in all respects to
     the requirements of the Act and the Rules and Regulations, and neither of
     such documents includes, or will include, any untrue statement of a
     material fact or omits, or will omit, to state any material fact required
     to be stated therein or necessary to make the statements therein not
     misleading. If the Effective Time of the Initial Registration Statement is
     subsequent to the execution and delivery of this Agreement: on the
     Effective Date of the Initial Registration Statement, the Initial
     Registration Statement and the Prospectus will conform in all respects to
     the requirements of the Act and the Rules and Regulations, none of such
     documents will include any untrue statement of a material fact or will omit
     to state any material fact required to be stated therein or necessary to
     make the statements therein not misleading, and no Additional Registration
     Statement has been or will be filed. The two preceding sentences do not
     apply to statements in or omissions from a Registration Statement or the
     Prospectus based upon written information furnished to the Company by any
     Underwriter through the Representatives specifically for use therein, it
     being understood and agreed that the only such information is that
     described as such in Section 7(b) hereof.

            (c)  The Company has been duly incorporated and is an existing
     corporation in good standing under the laws of the State of Delaware, with
     power and authority (corporate and other) to own its properties and conduct
     its business as described in the Prospectus; and the Company is duly
     qualified to do business as a foreign corporation in good standing in all
     other jurisdictions in which its ownership or lease of property or the
     conduct of its business requires such qualification.

            (d)  Each subsidiary of the Company has been duly incorporated or
     organized, as the case may be, and is an existing corporation or limited
     partnership, as the case may be, in good standing under the laws of the
     jurisdiction of its incorporation or organization, as the case may be, with
     power and authority (corporate and other) to own its properties and conduct
     its business as described in the Prospectus; and each subsidiary of the
     Company is duly qualified to do business as a foreign corporation in good
     standing in all other jurisdictions in which its ownership or lease of
     property or the conduct of its business requires such qualification; all of
     the issued and outstanding capital stock or partnership interests, as the
     case may be, of each subsidiary of the Company has been duly authorized and
     validly issued and is fully paid and nonassessable; and the capital stock
     or partnership interests, as the case may be, of each subsidiary owned by
     the Company, directly or through subsidiaries, is owned free from liens,
     encumbrances and defects.

                                      -3-
<PAGE>

            (e)  The Offered Securities and all other outstanding shares of
     capital stock of the Company have been duly authorized; all outstanding
     shares of capital stock of the Company are, and, when the Offered
     Securities have been delivered and paid for in accordance with this
     Agreement on each Closing Date (as defined below), such Offered Securities
     will have been, validly issued, fully paid and nonassessable and will
     conform to the description thereof contained in the Prospectus; and the
     stockholders of the Company have no preemptive rights with respect to the
     Securities.

            (f)  Except as disclosed in the Prospectus, there are no contracts,
     agreements or understandings between the Company and any person that would
     give rise to a valid claim against the Company or any Underwriter for a
     brokerage commission, finder's fee or other like payment in connection with
     this offering.

            (g)  There are no contracts, agreements or understandings between
     the Company and any person granting such person the right to require the
     Company to file a registration statement under the Act with respect to any
     securities of the Company owned or to be owned by such person or to require
     the Company to include such securities in the securities registered
     pursuant to a Registration Statement or in any securities being registered
     pursuant to any other registration statement filed by the Company under the
     Act that have not been validly waived or satisfied prior to the date
     hereof.

            (h)  The Offered Securities have been approved for listing on The
     Nasdaq Stock Market's National Market subject to notice of issuance.

            (i)  No consent, approval, authorization, or order of, or filing
     with, any governmental agency or body or any court is required for the
     consummation of the transactions contemplated by this Agreement in
     connection with the issuance and sale of the Offered Securities by the
     Company, except such as have been obtained and made under the Act and such
     as may be required under state securities laws.

            (j)  The execution, delivery and performance of this Agreement, and
     the issuance and sale of the Offered Securities will not result in a breach
     or violation of any of the terms and provisions of, or constitute a default
     under, any statute, any rule, regulation or order of any governmental
     agency or body or any court, domestic or foreign, having jurisdiction over
     the Company or any of its properties, or any agreement or instrument to
     which the Company is a party or by which the Company is bound or to which
     any of the properties of the Company is subject, or the charter or by-laws
     of the Company, and the Company has full power and authority to authorize,
     issue and sell the Offered Securities as contemplated by this Agreement.

            (k)  This Agreement has been duly authorized, executed and delivered
     by the Company.

            (l)  Except as disclosed in the Prospectus, the Company has good and
     marketable title to all real properties and all other properties and assets
     owned by them, in each case free from liens, encumbrances and defects that
     would materially affect the value thereof or materially interfere with the
     use made or to be made thereof by them; and except as disclosed in the
     Prospectus, the Company holds any leased real or personal property under
     valid and enforceable leases with no exceptions that would materially
     interfere with the use made or to be made thereof by it.

            (m)  The Company possesses adequate certificates, authorities or
     permits issued by appropriate governmental agencies or bodies necessary to
     conduct the business now operated by them and have not received any notice
     of proceedings relating to the revocation or modification of any such

                                      -4-
<PAGE>

     certificate, authority or permit that, if determined adversely to the
     Company, would individually or in the aggregate have a material adverse
     effect on th e condition (financial or other), business, properties or
     results of operations of the Company taken as a whole ("Material Adverse
     Effect").

            (n)  No labor dispute with the employees of the Company exists or,
     to the knowledge of the Company, is imminent that might have a Material
     Adverse Effect.

            (o)  The Company owns, possesses or can acquire on reasonable terms,
     adequate trademarks, trade names and other rights to inventions, know-how,
     patents, copyrights, confidential information and other intellectual
     property (collectively, "intellectual property rights") necessary to
     conduct the business now operated by it, or presently employed by it, and
     have not received any notice of infringement of or conflict with asserted
     rights of others with respect to any intellectual property rights that, if
     determined adversely to the Company, would individually or in the aggregate
     have a Material Adverse Effect. The intellectual property rights of the
     Company referred to in the Prospectus do not, to the Company's knowledge,
     infringe or conflict with any intellectual property right of any third
     party.

            (p)  Except as disclosed in the Prospectus, the Company is not in
     violation of any statute, any rule, regulation, decision or order of any
     governmental agency or body or any court, domestic or foreign, relating to
     the use, disposal or release of hazardous or toxic substances or relating
     to the protection or restoration of the environment or human exposure to
     hazardous or toxic substances (collectively, "environmental laws"), does
     not own or operate any real property contaminated with any substance that
     is subject to any environmental laws, is not liable for any off-site
     disposal or contamination pursuant to any environmental laws, or is not
     subject to any claim relating to any environmental laws, which violation,
     contamination, liability or claim would individually or in the aggregate
     have a Material Adverse Effect; and the Company is not aware of any pending
     investigation which might lead to such a claim.

            (q)  Except as disclosed in the Prospectus, there are no pending
     actions, suits or proceedings against or affecting the Company or any of
     its properties that, if determined adversely to the Company, would
     individually or in the aggregate have a Material Adverse Effect, or would
     materially and adversely affect the ability of the Company to perform its
     obligations under this Agreement, or which are otherwise material in the
     context of the sale of the Offered Securities; and no such actions, suits
     or proceedings are threatened or, to the Company's knowledge, contemplated.

            (r)  The financial statements included in each Registration
     Statement and the Prospectus present fairly the financial position of the
     Company as of the dates shown and its results of operations and cash flows
     for the periods shown, and such financial statements have been prepared in
     conformity with the generally accepted accounting principles in the United
     States applied on a consistent basis and the schedules included in each
     Registration Statement present fairly the information required to be stated
     therein.

            (s)  Except as disclosed in the Prospectus, since the date of the
     latest audited financial statements included in the Prospectus there has
     been no material adverse change, nor any development or event involving a
     prospective material adverse change, in the condition (financial or other),
     business, properties or results of operations of the Company taken as a
     whole, and, except as disclosed in or contemplated by the Prospectus, there
     has been no dividend or distribution of any kind declared, paid or made by
     the Company on any class of its capital stock.

                                      -5-
<PAGE>

            (t)  The Company is not and, after giving effect to the offering and
     sale of the Offered Securities and the application of the proceeds thereof
     as described in the Prospectus, will not be an "investment company" as
     defined in the Investment Company Act of 1940.

            (u)  Except as disclosed in the Prospectus, all outstanding
     Securities, and all securities convertible into or exercisable or
     exchangeable for Securities, are subject to valid and binding agreements
     (collectively, "Lock-up Agreements"), in a form agreed to by the Company
     and Credit Suisse First Boston Corporation ("CSFBC") that restrict the
     holders thereof from selling, making any short sale of, granting any option
     for the purchase of, or otherwise transferring or disposing of, any of such
     Securities, or any such securities convertible into or exercisable or
     exchangeable for Securities, for a period of 180 days after the date of the
     Prospectus without the prior written consent of CSFBC.

            (v)  Furthermore, the Company represents and warrants to the
     Underwriters that (i) the Registration Statement, the Prospectus and any
     preliminary prospectus comply, and any further amendments or supplements
     thereto will comply, with any applicable laws or regulations of foreign
     jurisdictions in which the Prospectus or any preliminary prospectus, as
     amended or supplemented, if applicable, are distributed in connection with
     the Directed Share Program, and that (ii) no authorization, approval,
     consent, license, order, registration or qualification of or with any
     government, governmental instrumentality or court, other than such as have
     been obtained, is necessary under the securities law and regulations of
     foreign jurisdictions in which the Directed Shares are offered outside the
     United States.

            (w)  The Company has not offered, or caused the Underwriters to
     offer, any offered Securities to any person pursuant to the Directed Share
     Program with the specific intent to unlawfully influence (i) a customer or
     supplier of the Company to alter the customer's or supplier's level or type
     of business with the Company or (ii) a trade journalist or publication to
     write or publish favorable information about the Company or its products.

            (x)  The first closing of the Company's Series E Preferred Stock
     financing was on September 5, 2000, and the second closing of Series E
     Preferred Stock was on October 17, 2000. There have been no subsequent
     closings or sales of Series E Preferred Stock after such date.

     3.     Purchase, Sale and Delivery of Offered Securities. On the basis of
the representations, warranties and agreements herein contained, but subject to
the terms and conditions herein set forth, the Company agrees to sell to the
Underwriters, and the Underwriters agree, severally and not jointly, to purchase
from the Company, at a purchase price of $        per share, the respective
numbers of shares of Firm Securities set forth opposite the names of the
Underwriters in Schedule A hereto.

     The Company will deliver the Firm Securities to the Representatives for the
accounts of the Underwriters, at the office of                              ,
against payment of the purchase price in Federal (same day) funds by official
bank check or checks or wire transfer to an account at a bank acceptable to
CSFBC drawn to the order of                             at the office of    ,
at      A.M., New York time, on                            , or at such other
time not later than seven full business days thereafter as CSFBC and the Company
determine, such time being herein referred to as the "First Closing Date". For
purposes of Rule 15c6-1 under the Securities Exchange Act of 1934, the First
Closing Date (if later than the otherwise applicable settlement date) shall be
the settlement date for payment of funds and delivery of securities for all the
Offered Securities sold pursuant to the offering. The certificates for the Firm
Securities so to be delivered will be in definitive form, in such denominations
and registered in such names as CSFBC

                                      -6-
<PAGE>

requests and will be made available for checking and packaging at the above
office of                at least 24 hours prior to the First Closing Date.

     In addition, upon written notice from CSFBC given to the Company from time
to time not more than 30 days subsequent to the date of the Prospectus, the
Underwriters may purchase all or less than all of the Optional Securities at the
purchase price per Security to be paid for the Firm Securities. The Company
agrees to sell to the Underwriters the number of shares of Optional Securities
specified in such notice and the Underwriters agree, severally and not jointly,
to purchase such Optional Securities. Such Optional Securities shall be
purchased for the account of each Underwriter in the same proportion as the
number of shares of Firm Securities set forth opposite such Underwriter's name
bears to the total number of shares of Firm Securities (subject to adjustment by
CSFBC to eliminate fractions) and may be purchased by the Underwriters only for
the purpose of covering over-allotments made in connection with the sale of the
Firm Securities. No Optional Securities shall be sold or delivered unless the
Firm Securities previously have been, or simultaneously are, sold and delivered.
The right to purchase the Optional Securities or any portion thereof may be
exercised from time to time and to the extent not previously exercised may be
surrendered and terminated at any time upon notice by CSFBC to the Company.

     Each time for the delivery of and payment for the Optional Securities,
being herein referred to as an "Optional Closing Date", which may be the First
Closing Date (the First Closing Date and each Optional Closing Date, if any,
being sometimes referred to as a "Closing Date"), shall be determined by CSFBC
but shall be not later than five full business days after written notice of
election to purchase Optional Securities is given. The Company will deliver the
Optional Securities being purchased on each Optional Closing Date to the
Representatives for the accounts of the several Underwriters, at the office of
          , against payment of the purchase price therefor in Federal (same day)
funds by official bank check or checks or wire transfer to an account at a bank
acceptable to CSFBC drawn to the order of                      , at the above
office of                     .   The certificates for the Optional Securities
being purchased on each Optional Closing Date will be in definitive form, in
such denominations and registered in such names as CSFBC requests upon
reasonable notice prior to such Optional Closing Date and will be made available
for checking and packaging at the above office of
at a reasonable time in advance of such Optional Closing Date.

     4.     Offering by Underwriters. It is understood that the several
Underwriters propose to offer the Offered Securities for sale to the public as
set forth in the Prospectus.

     5.     Certain Agreements of the Company. The Company agrees with the
several Underwriters that:

            (a)  If the Effective Time of the Initial Registration Statement is
     prior to the execution and delivery of this Agreement, the Company will
     file the Prospectus with the Commission pursuant to and in accordance with
     subparagraph (1) (or, if applicable and if consented to by CSFBC,
     subparagraph (4)) of Rule 424(b) not later than the earlier of (A) the
     second business day following the execution and delivery of this Agreement
     or (B) the fifteenth business day after the Effective Date of the Initial
     Registration Statement.

     The Company will advise CSFBC promptly of any such filing pursuant to Rule
     424(b). If the Effective Time of the Initial Registration Statement is
     prior to the execution and delivery of this Agreement and an additional
     registration statement is necessary to register a portion of the Offered
     Securities under the Act but the Effective Time thereof has not occurred as
     of such execution and delivery, the Company will file the additional
     registration statement or, if filed, will file a post-effective amendment
     thereto with the Commission pursuant to and in accordance with Rule 462(b)
     on or prior to 10:00 P.M., New York time, on the date of this Agreement or,
     if earlier, on or prior to

                                      -7-
<PAGE>

     the time the Prospectus is printed and distributed to any Underwriter, or
     will make such filing at such later date as shall have been consented to by
     CSFBC.

            (b)  The Company will advise CSFBC promptly of any proposal to amend
     or supplement the initial or any additional registration statement as filed
     or the related prospectus or the Initial Registration Statement, the
     Additional Registration Statement (if any) or the Prospectus and will not
     effect such amendment or supplementation without CSFBC's consent; and the
     Company will also advise CSFBC promptly of the effectiveness of each
     Registration Statement (if its Effective Time is subsequent to the
     execution and delivery of this Agreement) and of any amendment or
     supplementation of a Registration Statement or the Prospectus and of the
     institution by the Commission of any stop order proceedings in respect of a
     Registration Statement and will use its best efforts to prevent the
     issuance of any such stop order and to obtain as soon as possible its
     lifting, if issued.

            (c)  If, at any time when a prospectus relating to the Offered
     Securities is required to be delivered under the Act in connection with
     sales by any Underwriter or dealer, any event occurs as a result of which
     the Prospectus as then amended or supplemented would include an untrue
     statement of a material fact or omit to state any material fact necessary
     to make the statements therein, in the light of the circumstances under
     which they were made, not misleading, or if it is necessary at any time to
     amend the Prospectus to comply with the Act, the Company will promptly
     notify CSFBC of such event and will promptly prepare and file with the
     Commission, at its own expense, an amendment or supplement which will
     correct such statement or omission or an amendment which will effect such
     compliance. Neither CSFBC's consent to, nor the Underwriters' delivery of,
     any such amendment or supplement shall constitute a waiver of any of the
     conditions set forth in Section 6.

            (d)  As soon as practicable, but not later than the Availability
     Date (as defined below), the Company will make generally available to its
     securityholders an earnings statement covering a period of at least 12
     months beginning after the Effective Date of the Initial Registration
     Statement (or, if later, the Effective Date of the Additional Registration
     Statement) which will satisfy the provisions of Section 11(a) of the Act.
     For the purpose of the preceding sentence, "Availability Date" means the
     45th day after the end of the fourth fiscal quarter following the fiscal
     quarter that includes such Effective Date, except that, if such fourth
     fiscal quarter is the last quarter of the Company's fiscal year,
     "Availability Date" means the 90th day after the end of such fourth fiscal
     quarter.

            (e)  The Company will furnish to the Representatives copies of each
     Registration Statement (five of which will be signed and will include all
     exhibits), each related preliminary prospectus, and, so long as a
     prospectus relating to the Offered Securities is required to be delivered
     under the Act in connection with sales by any Underwriter or dealer, the
     Prospectus and all amendments and supplements to such documents, in each
     case in such quantities as CSFBC requests. The Prospectus shall be so
     furnished on or prior to 3:00 P.M., New York time, on the business day
     following the later of the execution and delivery of this Agreement or the
     Effective Time of the Initial Registration Statement. All other documents
     shall be so furnished as soon as available. The Company will pay the
     expenses of printing and distributing to the Underwriters all such
     documents.

            (f)  The Company will arrange for the qualification of the Offered
     Securities for sale under the laws of such jurisdictions as CSFBC
     designates and will continue such qualifications in effect so long as
     required for the distribution.

                                      -8-
<PAGE>

            (g)  During the period of five years hereafter, the Company will
     furnish to the Representatives and, upon request, to each of the other
     Underwriters, as soon as practicable after the end of each fiscal year, a
     copy of its annual report to stockholders for such year; and the Company
     will furnish to the Representatives (i) as soon as available, a copy of
     each report and any definitive proxy statement of the Company filed with
     the Commission under the Securities Exchange Act of 1934 or mailed to
     stockholders, and (ii) from time to time, such other information concerning
     the Company as CSFBC may reasonably request.

            (h)  The Company will pay all expenses incident to the performance
     of its obligations under this Agreement, for any filing fees and other
     expenses (including fees and disbursements of counsel) incurred in
     connection with qualification of the Offered Securities for sale under the
     laws of such jurisdictions as CSFBC designates and the printing of
     memoranda relating thereto for the filing fee incident to, and the
     reasonable fees and disbursements of counsel to the Underwriters in
     connection with, the review by the National Association of Securities
     Dealers, Inc. of the Offered Securities, for any travel expenses of the
     Company's officers and employees and any other expenses of the Company in
     connection with attending or hosting meetings with prospective purchasers
     of the Offered Securities and for expenses incurred in distributing
     preliminary prospectuses and the Prospectus (including any amendments and
     supplements thereto) to the Underwriters. In addition to the foregoing, the
     Company will pay to the Representatives on behalf of the Underwriters on
     the First Closing Date the sum of $         as a nonaccountable
     reimbursement of the Underwriters' other expenses. Such amount may be
     deducted from the purchase price for the Offered Securities set forth in
     Section 3.

            (i)  For a period of 180 days after the date of the initial public
     offering of the Offered Securities, the Company will not offer, sell,
     contract to sell, pledge or otherwise dispose of, directly or indirectly,
     or file with the Commission a registration statement under the Act relating
     to, any additional shares of its Securities or securities convertible into
     or exchangeable or exercisable for any shares of its Securities, or
     publicly disclose the intention to make any such offer, sale, pledge,
     disposition or filing, without the prior written consent of CSFBC, except
     (i) the filing of a Registration Statement on Form S-8, (ii) grants of
     employee stock options pursuant to the terms disclosed in the Prospectus
     and a plan in effect on the date hereof, (iii) issuances of Securities
     pursuant to the exercise of employee stock options outstanding on the date
     hereof, or (iv) issuances of Securities pursuant to the conversion or
     exchange of convertible or exchangeable securities or the exercise of
     warrants or options, in each case outstanding on the date hereof.

            (j)  The Company agrees to use its best efforts to cause (i) each of
     its directors, officers and stockholders and (ii) each person who acquires
     Securities of the Company pursuant to the exercise of any option or right
     granted under the 1997 Stock Option Plan to sign an agreement that
     restricts such person from selling, making any short sale of, granting any
     option for the purchase of, or otherwise transferring or disposing of, any
     of such Securities, or any such securities convertible into or exercisable
     or exchangeable for Securities, for a period of 180 days after the date of
     the Prospectus without the prior written consent of CSFBC; and the Company
     will (i) enforce the terms of each such agreement and (ii) issue and impose
     a stop-transfer instruction with the Company's transfer agent in order to
     enforce the foregoing lock-up agreements.

            (k)  The Company will (i) enforce the terms of each Lock-up
     Agreement, and (ii) issue stop-transfer instructions to the transfer agent
     for the Securities with respect to any transaction or contemplated
     transaction that would constitute a breach of or default under the
     applicable Lock-up Agreement. In addition, except with the prior written
     consent of CSFBC, the Company agrees (i)

                                      -9-
<PAGE>

     not to amend or terminate, or waive any right under, any Lock-up Agreement,
     or take any other action that would directly or indirectly have the same
     eff ect as an amendment or termination, or waiver of any right under any
     Lock-up Agreement, that would permit any holder of Securities, or any
     securities convertible into, or exercisable or exchangeable for,
     Securities, to make any short sale of, grant any option for the purchase
     of, or otherwise transfer or dispose of, any such Securities or other
     securities, prior to the expiration of the 180 days after the date of the
     Prospectus and (ii) not to consent to any sale, short sale, grant of an
     option for the purchase of, or other disposition or transfer of shares of
     Securities, or securities convertible into or exercisable or exchangeable
     for Securities, subject to a Lock-up Agreement.

            (l)  In connection with the Directed Share Program, the Company will
     ensure that the Directed Shares will be restricted to the extent required
     by the National Association of Securities Dealers, Inc. (the "NASD") or the
     NASD rules from sale, transfer, assignment, pledge or hypothecation for a
     period of three months following the date of the effectiveness of the
     Registration Statement. The Designated Underwriter will notify the Company
     as to which Participants will need to be so restricted. The Company will
     direct the transfer agent to place stop transfer restrictions upon such
     securities for such period of time.

            (m)  The Company will pay all fees and disbursements of counsel
     incurred by the Underwriters in connection with the Directed Share Program
     and stamp duties, similar taxes or duties or other taxes, if any, incurred
     by the underwriters in connection with the Directed Share Program.

            Furthermore, the Company covenants with the Underwriters that the
     Company will comply with all applicable securities and other applicable
     laws, rules and regulations in each foreign jurisdiction in which the
     Directed Shares are offered in connection with the Directed Share Program.

     6.     Conditions of the Obligations of the Underwriters. The obligations
of the several Underwriters to purchase and pay for the Firm Securities on the
First Closing Date and the Optional Securities to be purchased on each Optional
Closing Date will be subject to the accuracy of the representations and
warranties on the part of the Company herein, to the accuracy of the statements
of Company officers made pursuant to the provisions hereof, to the performance
by the Company of its obligations hereunder and to the following additional
conditions precedent:

            (a)  The Representatives shall have received a letter, dated the
     date of delivery thereof (which, if the Effective Time of the Initial
     Registration Statement is prior to the execution and delivery of this
     Agreement, shall be on or prior to the date of this Agreement or, if the
     Effective Time of the Initial Registration Statement is subsequent to the
     execution and delivery of this Agreement, shall be prior to the filing of
     the amendment or post-effective amendment to the registration statement to
     be filed shortly prior to such Effective Time), of Ernst & Young LLP
     confirming that they are independent public accountants within the meaning
     of the Act and the applicable published Rules and Regulations thereunder
     and stating to the effect that:

          (i)   in their opinion the financial statements and schedules
          examined by them and included in the Registration Statements comply as
          to form in all material respects with the applicable accounting
          requirements of the Act and the related published Rules and
          Regulations;

          (ii)  they have performed the procedures specified by the American
          Institute of Certified Public Accountants for a review of interim
          financial information as described in

                                      -10-
<PAGE>

          Statement of Auditing Standards No. 71, Interim Financial Information,
          on the unaudited financial statements included in t he Registration
          Statements;

          (iii)  on the basis of the review referred to in clause (ii) above, a
          reading of the latest available interim financial statements of the
          Company, inquiries of officials of the Company who have responsibility
          for financial and accounting matters and other specified procedures,
          nothing came to their attention that caused them to believe that:

               (A)  the unaudited financial statements included in the
               Registration Statements do not comply as to form in all material
               respects with the applicable accounting requirements of the Act
               and the related published Rules and Regulations or any material
               modifications should be made to such unaudited financial
               statements for them to be in conformity with generally accepted
               accounting principles;

               (B)  at the date of the latest available balance sheet read by
               such accountants, or at a subsequent specified date not more than
               three business days prior to the date of this Agreement, there
               was any change in the capital stock or any increase in short-term
               indebtedness or long-term debt of the Company, at the date of the
               latest available balance sheet read by such accountants, there
               was any decrease in consolidated net current assets or net
               assets, as compared with amounts shown on the latest balance
               sheet included in the Prospectus; or

               (C) for the period from the closing date of the latest income
               statement included in the Prospectus to the closing date of the
               latest available income statement read by such accountants there
               were any decreases, as compared with the corresponding period of
               the previous year in consolidated net sales, net operating income
               or in the total or per share amounts of consolidated net income,
               except in all cases set forth in clauses and above for changes,
               increases or decreases which the Prospectus discloses have
               occurred or may occur or which are described in such letter; and

          (iv) they have compared specified dollar amounts (or percentages
          derived from such dollar amounts) and other financial information
          contained in the Registration Statements (in each case to the extent
          that such dollar amounts, percentages and other financial information
          are derived from the general accounting records of the Company subject
          to the internal controls of the Company's accounting system or are
          derived directly from such records by analysis or computation) with
          the results obtained from inquiries, a reading of such general
          accounting records and other procedures specified in such letter and
          have found such dollar amounts, percentages and other financial
          information to be in agreement with such results, except as otherwise
          specified in such letter.

For purposes of this subsection, (i) if the Effective Time of the Initial
Registration Statement is subsequent to the execution and delivery of this
Agreement, "Registration Statements" shall mean the initial registration
statement as proposed to be amended by the amendment or post-effective amendment
to be filed shortly prior to its Effective Time, (ii) if the Effective Time of
the Initial Registration Statement is prior to the execution and delivery of
this Agreement but the Effective Time of the Additional Registration is
subsequent to such execution and delivery, "Registration Statements" shall mean
the Initial Registration Statement and the additional registration statement as
proposed to be filed or as proposed to be amended by the post-effective

                                      -11-
<PAGE>

amendment to be filed shortly prior to its Effective Time, and (iii)
"Prospectus" shall mean the prospectus included in the Registration Statements.

        (b)  If the Effective Time of the Initial Registration Statement is not
prior to the execution and delivery of this Agreement, such Effective Time shall
have occurred not later than 10:00 P.M., New York time, on the date of this
Agreement or such later date as shall have been consented to by CSFBC. If the
Effective Time of the Additional Registration Statement (if any) is not prior to
the execution and delivery of this Agreement, such Effective Time shall have
occurred not later than 10:00 P.M., New York time, on the date of this Agreement
or, if earlier, the time the Prospectus is printed and distributed to any
Underwriter, or shall have occurred at such later date as shall have been
consented to by CSFBC. If the Effective Time of the Initial Registration
Statement is prior to the execution and delivery of this Agreement, the
Prospectus shall have been filed with the Commission in accordance with the
Rules and Regulations and Section 5(a) of this Agreement. Prior to such Closing
Date, no stop order suspending the effectiveness of a Registration Statement
shall have been issued and no proceedings for that purpose shall have been
instituted or, to the knowledge of the Company or the Representatives, shall be
contemplated by the Commission.

        (c)  Subsequent to the execution and delivery of this Agreement, there
shall not have occurred (i) any change, or any development or event involving a
prospective change, in the condition (financial or other), business, properties
or results of operations of the Company which, in the judgment of a majority in
interest of the Underwriters including the Representatives, is material and
adverse and makes it impractical or inadvisable to proceed with completion of
the public offering or the sale of and payment for the Offered Securities; (ii)
any downgrading in the rating of any debt securities or preferred stock of the
Company by any "nationally recognized statistical rating organization" (as
defined for purposes of Rule 436(g) under the Act), or any public announcement
that any such organization has under surveillance or review its rating of any
debt securities or preferred stock of the Company (other than an announcement
with positive implications of a possible upgrading, and no implication of a
possible downgrading, of such rating); (iii) any material suspension or material
limitation of trading in securities generally on the New York Stock Exchange, or
any setting of minimum prices for trading on such exchange, or any suspension of
trading of any securities of the Company on any exchange or in the over-the-
counter market; (iv) any banking moratorium declared by U.S. Federal or New York
banking authorities; or (v) any outbreak or escalation of major hostilities in
which the United States is involved, any declaration of war by Congress or any
other substantial national or international calamity or emergency if, in the
judgment of a majority in interest of the Underwriters including the
Representatives, the effect of any such outbreak, escalation, declaration,
calamity or emergency makes it impractical or inadvisable to proceed with
completion of the public offering or the sale of and payment for the Offered
Securities.

        (d)  The Representatives shall have received an opinion, dated such
Closing Date, of Gunderson Dettmer Stough Villeneuve Franklin & Hachigian,
L.L.P., counsel for the Company, to the effect that:

                (i)  The Company has been duly incorporated and is an existing
     corporation in good standing under the laws of the State of Delaware, with
     corporate power and authority to own its properties and conduct its
     business as described in the Prospectus; and the Company is duly qualified
     to do business as a foreign corporation in good standing in all other
     jurisdictions in which its ownership or lease of property or the conduct of
     its business requires such qualification;

                                      -12-
<PAGE>

                (ii)  The Offered Securities delivered on such Closing Date and
     all other outstanding shares of the Common Stock of the Company have been
     duly authorized and validly issued, are fully paid and nonassessable and
     conform to the description thereof contained in the Prospectus; and the
     stockholders of the Company have no preemptive rights with respect to the
     Securities;

                (iii) There are no contracts, agreements or understandings known
     to such counsel between the Company and any person granting such person the
     right to require the Company to file a registration statement under the Act
     with respect to any securities of the Company owned or to be owned by such
     person or to require the Company to include such securities in the
     securities registered pursuant to the Registration Statement or in any
     securities being registered pursuant to any other registration statement
     filed by the Company under the Act that have not been validly waived or
     satisfied prior to the date hereof;

                (iv)   No consent, approval, authorization or order of, or
     filing with, any governmental agency or body or any court is required for
     the consummation of the transactions contemplated by this Agreement in
     connection with the issuance or sale of the Offered Securities by the
     Company, except such as have been obtained and made under the Act and such
     as may be required under state securities laws;

                (v)    The Company is not and, after giving effect to the
     offering and sale of the Offered Securities and the application of the
     proceeds thereof as described in the Prospectus, will not be an "investment
     company" as defined in the Investment Company Act of 1940.

                (vi)   The execution, delivery and performance of this Agreement
     and the issuance and sale of the Offered Securities will not result in a
     breach or violation of any of the terms and provisions of, or constitute a
     default under, any statute, any rule, regulation or order of any
     governmental agency or body or any court having jurisdiction over the
     Company or any of its properties, or any agreement or instrument to which
     the Company is a party or by which the Company is bound or to which any of
     the properties of the Company is subject, or the charter or by-laws of the
     Company, and the Company has full power and authority to authorize, issue
     and sell the Offered Securities as contemplated by this Agreement;

                (vii)  The Initial Registration Statement was declared effective
     under the Act as of the date and time specified in such opinion, the
     Additional Registration Statement (if any) was filed and became effective
     under the Act as of the date and time (if determinable) specified in such
     opinion, the Prospectus either was filed with the Commission pursuant to
     the subparagraph of Rule 424(b) specified in such opinion on the date
     specified therein or was included in the Initial Registration Statement or
     the Additional Registration Statement (as the case may be), and, to the
     best of the knowledge of such counsel, no stop order suspending the
     effectiveness of a Registration Statement or any part thereof has been
     issued and no proceedings for that purpose have been instituted or are
     pending or contemplated under the Act, and each Registration Statement and
     the Prospectus, and each amendment or supplement thereto, as of their
     respective effective or issue dates, complied as to form in all material
     respects with the requirements of the Act and the Rules and Regulations;
     such counsel have no reason to believe that any part of a Registration
     Statement or any amendment thereto, as of its effective date or as of such

                                      -13-
<PAGE>

     Closing Date, contained any untrue statement of a material fact or omitted
     to state any material fact required to be stated therein or necessary to
     make the statements therein not misleading or that the Prospectus or any
     amendment or supplement thereto, as of its issue date or as of such Closing
     Date, contained any untrue statement of a material fact or omitted to state
     any material fact necessary in order to make the statements therein, in the
     light of the circumstances under which they were made, not misleading; t he
     descriptions in the Registration Statements and Prospectus of statutes,
     legal and governmental proceedings and contracts and other documents are
     accurate and fairly present the information required to be shown; and such
     counsel do not know of any legal or governmental proceedings required to be
     described in a Registration Statement or the Prospectus which are not
     described as required or of any contracts or documents of a character
     required to be described in a Registration Statement or the Prospectus or
     to be filed as exhibits to a Registration Statement which are not described
     and filed as required; it being understood that such counsel need express
     no opinion as to the financial statements or other financial data contained
     in the Registration Statements or the Prospectus; and

                (viii) This Agreement has been duly authorized, executed and
     delivered by the Company.

     (e)  The Representatives shall have received from Wilson Sonsini Goodrich &
   Rosati, Professional Corporation, counsel for the Underwriters, such opinion
   or opinions, dated such Closing Date, with respect to the incorporation of
   the Company, the validity of the Offered Securities delivered on such Closing
   Date, the Registration Statements, the Prospectus and other related matters
   as the Representatives may require, and the Company shall have furnished to
   such counsel such documents as they request for the purpose of enabling them
   to pass upon such matters.

     (f)  The Representatives shall have received a certificate, dated such
   Closing Date, of the President or any Vice President and a principal
   financial or accounting officer of the Company in which such officers, to the
   best of their knowledge after reasonable investigation, shall state that: the
   representations and warranties of the Company in this Agreement are true and
   correct; the Company has complied with all agreements and satisfied all
   conditions on its part to be performed or satisfied hereunder at or prior to
   such Closing Date; no stop order suspending the effectiveness of any
   Registration Statement has been issued and no proceedings for that purpose
   have been instituted or are contemplated by the Commission; the Additional
   Registration Statement (if any) satisfying the requirements of subparagraphs
   (1) and (3) of Rule 462(b) was filed pursuant to Rule 462(b), including
   payment of the applicable filing fee in accordance with Rule 111(a) or (b)
   under the Act, prior to the time the Prospectus was printed and distributed
   to any Underwriter; and, subsequent to the date of the most recent financial
   statements in the Prospectus, there has been no material adverse change, nor
   any development or event involving a prospective material adverse change, in
   the condition (financial or other), business, properties or results of
   operations of the Company except as set forth in or contemplated by the
   Prospectus or as described in such certificate.

     (g)  The Representatives shall have received a letter, dated such Closing
   Date, of Ernst & Young LLP which meets the requirements of subsection (a) of
   this Section, except that the specified date referred to in such subsection
   will be a date not more than three days prior to such Closing Date for the
   purposes of this subsection.

                                      -14-
<PAGE>

     (h)  On or prior to the date of this Agreement, the Representatives shall
   have received lockup letters from each of the executive officers, directors
   and holders of capital stock and securities exercisable for or convertible
   into capital stock of the Company.

The Company will furnish the Representatives with such conformed copies of such
opinions, certificates, letters and documents as the Representatives reasonably
requests.  CSFBC may in its sole discretion waive on behalf of the Underwriters
compliance with any conditions to the obligations of the Underwriters hereunder,
whether in respect of an Optional Closing Date or otherwise.

   7.   Indemnification and Contribution. (a) The Company will indemnify and
hold harmless each Underwriter, its partners, directors and officers and each
person, if any, who controls such Underwriter within the meaning of Section 15
of the Act, against any losses, claims, damages or liabilities, joint or
several, to which such Underwriter may become subject, under the Act or
otherwise, insofar as such losses, claims, damages or liabilities (or actions in
respect thereof) arise out of or are based upon any untrue statement or alleged
untrue statement of any material fact contained in any Registration Statement,
the Prospectus, or any amendment or supplement thereto, or any related
preliminary prospectus, or arise out of or are based upon the omission or
alleged omission to state therein a material fact required to be stated therein
or necessary to make the statements therein not misleading, and will reimburse
each Underwriter for any legal or other expenses reasonably incurred by such
Underwriter in connection with investigating or defending any such loss, claim,
damage, liability or action as such expenses are incurred; provided, however,
that the Company will not be liable in any such case to the extent that any such
loss, claim, damage or liability arises out of or is based upon an untrue
statement or alleged untrue statement in or omission or alleged omission from
any of such documents in reliance upon and in conformity with written
information furnished to the Company by any Underwriter through the
Representatives specifically for use therein, it being understood and agreed
that the only such information furnished by any Underwriter consists of the
information described as such in subsection (b) below.

   The Company agrees to indemnify and hold harmless the Designated Underwriter
and each person, if any, who controls the Designated Underwriter within the
meaning of either Section 15 of the Securities Act or Section 20 of the Exchange
Act (the "Designated Entities"), from and against any and all losses, claims,
damages and liabilities (including, without limitation, any legal or other
expenses reasonably incurred in connection with defending or investigating any
such action or claim) (i) caused by any untrue statement or alleged untrue
statement of a material fact contained in any material prepared by or with the
consent of the Company for distribution to Participants in connection with the
Directed Share Program or caused by any omission or alleged omission to state
therein a material fact required to be stated therein or necessary to make the
statements therein not misleading; (ii) caused by the failure of any Participant
to pay for and accept delivery of Directed Shares that the Participant agreed to
purchase; or (iii) damages or liabilities (or expenses relating thereto) that
are finally judicially determined to have resulted from the bad faith or gross
negligence of the Designated Entities.

   (b)  Each Underwriter will severally and not jointly indemnify and hold
harmless the Company, its directors and officers and each person, if any who
controls the Company within the meaning of Section 15 of the Act, against any
losses, claims, damages or liabilities to which the Company may become subject,
under the Act or otherwise, insofar as such losses, claims, damages or
liabilities (or actions in respect thereof) arise out of or are based upon any
untrue statement or alleged untrue statement of any material fact contained in
any Registration Statement, the Prospectus, or any amendment or supplement
thereto, or any related preliminary prospectus, or arise out of or are based
upon the omission or the alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, in each case to the extent, but only to the extent, that such untrue
statement or alleged untrue statement or omission or alleged omission was made
in reliance upon and in conformity with written

                                      -15-
<PAGE>

information furnished to the Company by such Underwriter through the
Representatives specifically for use therein, and will rei mburse any legal or
other expenses reasonably incurred by the Company in connection with
investigating or defending any such loss, claim, damage, liability or action as
such expenses are incurred, it being understood and agreed that the only such
information furnished by any Underwriter consists of (i) the following
information in the Prospectus furnished on behalf of each Underwriter: the
concession and reallowance figures appearing in the fourth paragraph under the
caption "Underwriting" and the information contained in the sixth paragraph
under the caption "Underwriting"; and (ii) the following information in the
Prospectus furnished on behalf of Thomas Weisel Partners, LLC: the information
in the fifteenth paragraph under the caption "Underwriting".

   (c)  Promptly after receipt by an indemnified party under this Section of
notice of the commencement of any action, such indemnified party will, if a
claim in respect thereof is to be made against the indemnifying party under
subsection (a) or (b) above, notify the indemnifying party of the commencement
thereof; but the omission so to notify the indemnifying party will not relieve
it from any liability which it may have to any indemnified party otherwise than
under subsection (a) or (b) above. In case any such action is brought against
any indemnified party and it notifies the indemnifying party of the commencement
thereof, the indemnifying party will be entitled to participate therein and, to
the extent that it may wish, jointly with any other indemnifying party similarly
notified, to assume the defense thereof, with counsel satisfactory to such
indemnified party (who shall not, except with the consent of the indemnified
party, be counsel to the indemnifying party), and after notice from the
indemnifying party to such indemnified party of its election so to assume the
defense thereof, the indemnifying party will not be liable to such indemnified
party under this Section for any legal or other expenses subsequently incurred
by such indemnified party in connection with the defense thereof other than
reasonable costs of investigation. Notwithstanding anything contained herein to
the contrary, if indemnity may be sought pursuant to the last paragraph in
Section 7 (a) hereof in respect of such action or proceeding, then in addition
to such separate firm for the indemnified parties, the indemnifying party shall
be liable for the reasonable fees and expenses of not more than one separate
firm (in addition to any local counsel) for the Designated Underwriter for the
defense of any losses, claims, damages and liabilities arising out of the
Directed Share Program, and all persons, if any, who control the Designated
Underwriter within the meaning of either Section 15 of the Act of Section 20 of
the Exchange Act. No indemnifying party shall, without the prior written consent
of the indemnified party, effect any settlement of any pending or threatened
action in respect of which any indemnified party is or could have been a party
and indemnity could have been sought hereunder by such indemnified party unless
such settlement (i) includes an unconditional release of such indemnified party
from all liability on any claims that are the subject matter of such action and
(ii) does not include a statement as to, or an admission of, fault, culpability
or a failure to act by or on behalf of an indemnified party.

   (d)  If the indemnification provided for in this Section is unavailable or
insufficient to hold harmless an indemnified party under subsection (a) or (b)
above, then each indemnifying party shall contribute to the amount paid or
payable by such indemnified party as a result of the losses, claims, damages or
liabilities referred to in subsection (a) or (b) above (i) in such proportion as
is appropriate to reflect the relative benefits received by the Company on the
one hand and the Underwriters on the other from the offering of the Securities
or (ii) if the allocation provided by clause (i) above is not permitted by
applicable law, in such proportion as is appropriate to reflect not only the
relative benefits referred to in clause (i) above but also the relative fault of
the Company on the one hand and the Underwriters on the other in connection with
the statements or omissions which resulted in such losses, claims, damages or
liabilities as well as any other relevant equitable considerations. The relative
benefits received by the Company on the one hand and the Underwriters on the
other shall be deemed to be in the same proportion as the total net proceeds
from the offering (before deducting expenses) received by the Company bear to
the total underwriting discounts and commissions received by the Underwriters.
The relative fault shall be

                                      -16-
<PAGE>

determined by reference to, among other things, whether the untrue or alleged
untrue statement of a material fac t or the omission or alleged omission to
state a material fact relates to information supplied by the Company or the
Underwriters and the parties' relative intent, knowledge, access to information
and opportunity to correct or prevent such untrue statement or omission. The
amount paid by an indemnified party as a result of the losses, claims, damages
or liabilities referred to in the first sentence of this subsection (d) shall be
deemed to include any legal or other expenses reasonably incurred by such
indemnified party in connection with investigating or defending any action or
claim which is the subject of this subsection (d). Notwithstanding the
provisions of this subsection (d), no Underwriter shall be required to
contribute any amount in excess of the amount by which the total price at which
the Securities underwritten by it and distributed to the public were offered to
the public exceeds the amount of any damages which such Underwriter has
otherwise been required to pay by reason of such untrue or alleged untrue
statement or omission or alleged omission. No person guilty of fraudulent
misrepresentation (within the meaning of Section 11(f) of the Act) shall be
entitled to contribution from any person who was not guilty of such fraudulent
misrepresentation. The Underwriters' obligations in this subsection (d) to
contribute are several in proportion to their respective underwriting
obligations and not joint.

   (e)  The obligations of the Company under this Section shall be in addition
to any liability which the Company may otherwise have and shall extend, upon the
same terms and conditions, to each person, if any, who controls any Underwriter
within the meaning of the Act; and the obligations of the Underwriters under
this Section shall be in addition to any liability which the respective
Underwriters may otherwise have and shall extend, upon the same terms and
conditions, to each director of the Company, to each officer of the Company who
has signed a Registration Statement and to each person, if any, who controls the
Company within the meaning of the Act.

   8.  Default of Underwriters.  If any Underwriter or Underwriters default in
their obligations to purchase Offered Securities hereunder on either the First
or any Optional Closing Date and the aggregate number of shares of Offered
Securities that such defaulting Underwriter or Underwriters agreed but failed to
purchase does not exceed 10% of the total number of shares of Offered Securities
that the Underwriters are obligated to purchase on such Closing Date, CSFBC may
make arrangements satisfactory to the Company for the purchase of such Offered
Securities by other persons, including any of the Underwriters, but if no such
arrangements are made by such Closing Date, the non-defaulting Underwriters
shall be obligated severally, in proportion to their respective commitments
hereunder, to purchase the Offered Securities that such defaulting Underwriters
agreed but failed to purchase on such Closing Date. If any Underwriter or
Underwriters so default and the aggregate number of shares of Offered Securities
with respect to which such default or defaults occur exceeds 10% of the total
number of shares of Offered Securities that the Underwriters are obligated to
purchase on such Closing Date and arrangements satisfactory to CSFBC and the
Company for the purchase of such Offered Securities by other persons are not
made within 36 hours after such default, this Agreement will terminate without
liability on the part of any non-defaulting Underwriter or the Company, except
as provided in Section 9 If a QIU is used change the reference to - Section 10
(provided that if such default occurs with respect to Optional Securities after
the First Closing Date, this Agreement will not terminate as to the Firm
Securities or any Optional Securities purchased prior to such termination). As
used in this Agreement, the term "Underwriter" includes any person substituted
for an Underwriter under this Section.  Nothing herein will relieve a defaulting
Underwriter from liability for its default.

   9.  Survival of Certain Representations and Obligations.  The respective
indemnities, agreements, representations, warranties and other statements of the
Company or its officers and of the several Underwriters set forth in or made
pursuant to this Agreement will remain in full force and effect, regardless of
any investigation, or statement as to the results thereof, made by or on behalf
of any Underwriter, the Company or any of their respective representatives,
officers or directors or any controlling

                                      -17-
<PAGE>

person, and will survive delivery of and payment for the Offered Securities. If
this Agreement is terminated pursuant to Section 8 or if for any reason the
purchase of the Offered Securities by the Underwriters is not consummated, the
Company shall remain responsible for the expenses to be paid or reimbursed by it
pursuant to Section 5 and the respective obligations of the Company and the
Underwriters pursuant to Section 7 and the obligations of the Company pursuant
to Section 9 shall remain in effect, and if any Offered Securities have been
purchased hereunder the representations and warranties in Section 2 and all
obligations under Section 5 shall also remain in effect. If the purchase of the
Offered Securities by the Underwriters is not consummated for any reason other
than solely because of the termination of this Agreement pursuant to Section 8
or the occurrence of any event specified in clause (iii), (iv) or (v) of Section
6(c), the Company will reimburse the Underwriters for all out-of-pocket expenses
(including fees and disbursements of counsel) reasonably incurred by them in
connection with the offering of the Offered Securities.

     10.   Notices. All communications hereunder will be in writing and, if sent
to the Underwriters, will be mailed, delivered or telegraphed and confirmed to
the Representatives, c/o Credit Suisse First Boston Corporation, Eleven Madison
Avenue, New York, N.Y. 10010-3629, Attention: Transactions Advisory Group, or,
if sent to the Company, will be mailed, delivered or telegraphed and confirmed
to it at        , Attention:         ; provided, however, that any notice to an
Underwriter pursuant to Section 7 will be mailed, delivered or telegraphed and
confirmed to such Underwriter.

     11.   Successors. This Agreement will inure to the benefit of and be
binding upon the parties hereto and their respective successors and the officers
and directors and controlling persons referred to in Section 7, and no other
person will have any right or obligation hereunder.

     12.   Representation of Underwriters.  The Representatives will act for the
several Underwriters in connection with this financing, and any action under
this Agreement taken by the Representatives jointly or by CSFBC  will be binding
upon all the Underwriters.

     13.   Counterparts.  This Agreement may be executed in any number of
counterparts, each of which shall be deemed to be an original, but all such
counterparts shall together constitute one and the same Agreement.

     14.   Applicable Law. This Agreement shall be governed by, and construed in
accordance with, the laws of the State of New York, without regard to principles
of conflicts of laws.

     The Company hereby submits to the non-exclusive jurisdiction of the Federal
and state courts in the Borough of Manhattan in The City of New York in any suit
or proceeding arising out of or relating to this Agreement or the transactions
contemplated hereby.  Notice given pursuant to Section 10 hereof shall be deemed
in every respect effective service of process upon the Company in any such suit
or proceeding.  The Company further agrees to take any and all action as may be
necessary to maintain such designation and appointment of such agent in full
force and effect for a period of seven years from the date of this Agreement.

                                      -18-
<PAGE>

  If the foregoing is in accordance with the Representatives'  understanding of
our agreement, kindly sign and return to the Company one of the counterparts
hereof, whereupon it will become a binding agreement between the Company and the
several Underwriters in accordance with its terms.

                        Very truly yours,

                                Chorum Technologies Inc.

                                        By......................................
                                           Scott C. Grout
                                           President and Chief Executive Officer


The foregoing Underwriting Agreement is hereby
confirmed and accepted as of the date first above
written.


  Credit Suisse First Boston Corporation
  Banc of America Securities LLC
  CIBC World Markets Corp.
  Thomas Weisel Partners LLC
     Acting on behalf of themselves and as the
       Representatives of the several
        Underwriters

  By  Credit Suisse First Boston Corporation


   By.......................................................
         Insert title

                                      -19-
<PAGE>

                                  SCHEDULE A



                Underwriter
                -----------
                                                                    Number of
                                                                 Firm Securities
                                                                 ---------------


Credit Suisse First Boston Corporation...................

Banc of America Securities LLC...........................

CIBC World Markets Corp..................................

Thomas Weisel Partners LLC...............................


















                                                               ---------------
               Total.....................................      $
                                                               ===============


                                      -20-