<PAGE>   1

                                                                    EXHIBIT 10.3



                         RELEASE AND AMENDMENT AGREEMENT

         This RELEASE AND AMENDMENT AGREEMENT (this "Release") is made this 9th
day of April, 2001, by and among ANTEC CORPORATION, a corporation organized
under the laws of Delaware (the "Company"), BROADBAND PARENT CORPORATION, a
corporation organized under the laws of Delaware ("Newco"), BROADBAND TRANSITION
CORPORATION, a corporation organized under the laws of Delaware ("Transition"),
NORTEL NETWORKS INC., a corporation organized under the laws of Delaware
("Nortel Networks"), NORTEL NETWORKS LLC, a limited liability company organized
under the laws of Delaware ("Nortel Networks LLC"), and ARRIS INTERACTIVE
L.L.C., a limited liability company organized under the laws of Delaware
("Existing Venture"). The parties to this Release are collectively referred to
as the "Parties". Capitalized terms used and not otherwise defined herein shall
have the respective meanings given them in the Agreement and Plan of
Reorganization, dated as of October 18, 2000 and amended the date hereof, by and
among the parties thereto (the "Reorganization Agreement").

         WHEREAS, the Company, Newco, Transition, Nortel Networks, Nortel
Networks LLC, and Existing Venture have entered into the Reorganization
Agreement, whereby the parties agreed: (1) that Transition would merge with and
into the Company (the "Merger") so that the Company would be the surviving
corporation in the Merger and a wholly-owned subsidiary of Newco and the
stockholders of the Company would receive shares of Newco Common Stock and (2)
that Nortel Networks LLC would contribute its interest in the Existing Venture
to Newco in exchange for shares of Newco Common Stock;

         WHEREAS, the Company, Nortel Networks, Existing Venture and Systems
Integration Venture L.L.C., a Delaware limited liability company, the existence
of which in the State of Delaware was terminated on September 21, 1998 ("SI
Venture"), are parties to the First Framework Agreement, dated as of November 1,
1995 (the "First Framework Agreement");

         WHEREAS, the Company, Nortel Networks, Nortel Networks LLC, and
Existing Venture are parties to the Second Framework Agreement, dated as of
March 31, 1999 (the "Second Framework Agreement");

         WHEREAS, Existing Venture and Nortel Networks are parties to the
Products Distributor Agreement dated as of November 17, 1995 (the "First
Distributor Agreement");

         WHEREAS, Existing Venture and Nortel Networks are parties to the Second
Products Distributor Agreement dated as of March 31, 1999 (the "Second
Distributor Agreement");

         WHEREAS, Existing Venture and Nortel Networks are parties to the
International Products Distributor Agreement dated as of June 10, 1997, as
amended by a memorandum of agreement, dated as of September 3, 1997, and further
amended by Amendment No. 1 to International Products Distributor Agreement,
dated as of March 31, 1999 (the "International Distributor Agreement");

         WHEREAS, the Company and Nortel Networks LLC are parties to the Amended
and Restated LLC Agreement of Existing Venture, dated as of March 31, 1999 (the
"LLC Agreement");


<PAGE>   2

         WHEREAS, Nortel Networks and Existing Venture are parties to the
License Agreement dated as of November 17, 1995, as amended by that certain
Amendment to License Agreement, dated as of March 31, 1999 between Existing
Venture, Nortel Networks Limited, a Canadian corporation ("Nortel Networks
Ltd."), and Nortel Networks (the "Nortel Networks License Agreement");

         WHEREAS, Nortel Networks, the Company and Existing Venture are parties
to the Intellectual Property Rights Agreement dated as of November 17, 1995, as
amended by that certain Amendment to Intellectual Property Rights Agreement
dated as of March 31, 1999, as amended by the Amendment to Intellectual Property
Rights Agreement (the "IP Rights Agreement", together with the First Framework
Agreement, the Second Framework Agreement, the First Distributor Agreement, the
Second Distributor Agreement, the International Distributor Agreement, the LLC
Agreement, and the Nortel Networks License Agreement, the "Arris Documents");

         WHEREAS, Mr. Robert Stanzione, on behalf of the Company, and Mr. Oscar
Rodriguez, on behalf of Nortel Networks and Nortel Networks LLC (together with
their respective Affiliates, including without limitation Nortel Networks Ltd.,
the "Nortel Parties"), exchanged correspondence through electronic means on
November 6, 2000, November 10, 2000 and November 13, 2000 regarding the sale of
certain products and/or services by one or more of the Nortel Parties to
Callahan Associates and/or its subsidiaries and other Affiliates, including but
not limited to Kabel NordRhein-Westfalen GmbH & Co KG and Callahan Associates
International, (collectively, the "Subject Customer") and certain transactions
ancillary thereto (the "November Correspondence");

         WHEREAS, on February 13, 2001, Mr. Robert Stanzione, on behalf of the
Company, sent further correspondence through electronic means to Mr. Oscar
Rodriguez and Mr. Michael Pangia, on behalf of the Nortel Parties (the "February
Correspondence"), relating to the same subject matter as the November
Correspondence (the November Correspondence and the February Correspondence,
together will any other written or oral modifications of any thereof, the
"Correspondence");

         WHEREAS, the Nortel Parties would not proceed with the Merger without
the release of any and all claims that each of the Company, Newco, Transition,
and Existing Venture (collectively, the "Antec Parties"), on the one hand, has
or may have against any of the Nortel Parties, the Existing Venture or any of
their respective agents, representatives, servants, employees, assigns, heirs,
subsidiaries, Affiliates and successors in interest (collectively, the "Released
Parties"), on the other hand, regarding any breach or violation of the
restrictions and/or conditions on transactions with third parties in the Arris
Documents and/or in the Correspondence to the extent that any such breach or
violation relates to (i) any actual or proposed sale of products and/or services
to the Subject Customer by any of the Released Parties, and/or (ii) any
activities (including, without limitation, demonstration and testing activities
and marketing activities) relating or incidental thereto (collectively, the
"Subject Activities"); and

         WHEREAS, the Nortel Parties also would not proceed with the Merger
without the amendment and modification of the Arris Documents (as the same may
have been amended or otherwise modified by the Correspondence) so as to remove
the Subject Activities from the


                                       2
<PAGE>   3

scope thereof and allow the Nortel Parties to engage in any or all Subject
Activities from and after the date hereof with no restrictions or conditions
imposed by the Arris Documents (as the same may have been so amended or
otherwise modified).

         NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Parties hereto agree as
follows:

         1.       The Antec Parties, and their respective agents,
representatives, servants, employees, assigns, heirs, subsidiaries, affiliates
and successors in interest, do hereby remise, release and forever discharge the
Released Parties of and from any and all debts, demands, actions, causes of
action, suits, accounts, covenants, contracts, agreements, damages, and any and
all claims, demands, and liabilities related to restrictions and/or conditions
on transactions with third parties in the Arris Documents and/or in the
Correspondence, including but not limited to Section 4.01 of the First Framework
Agreement and Section 4.01 of the Second Framework Agreement and all other
non-competition provisions in the Arris Documents, to the extent that such
restrictions, conditions or provisions were breached or violated as a result of,
or in connection with, any of the Subject Activities (collectively, the
"Released Claims").

         2.       The Parties hereby agree that all of the Arris Documents (as
the same may have been amended or otherwise modified by the Correspondence), and
any and all agreements and understandings between the Parties that are or may
have been reached by reason of, or in connection with, the Correspondence, shall
be, and hereby are, amended and modified in all relevant respects, to the full
extent necessary or advisable, so as to (i) remove the Subject Activities from
the scope of the restrictions and/or conditions therein on transactions with
third parties that are applicable to any of the Released Parties, and (ii) allow
the Released Parties, at all times or from time to time after effectiveness of
this Release, to engage in any or all Subject Activities free of any and all
restrictions and conditions therein.

         3.       This Release is agreed to by each of the Antec Parties and the
Nortel Parties with full knowledge of its terms, with advice of counsel, and for
the purpose of settling any and all Released Claims.

         4.       This Release may be executed in one or more counterparts, each
of which when executed shall be deemed to constitute an original but all of
which when taken together shall constitute one and the same instrument.

         5.       This Release shall be governed by, and interpreted in
accordance with, the laws of the State of Delaware, without regard to the
conflict of law principles thereof.


                                       3
<PAGE>   4



         IN WITNESS WHEREOF, the parties hereto have caused this Release to be
executed on the day and year first above written.

                                     ANTEC CORPORATION

                                     By: /s/ Lawrence A. Margolis
                                         ---------------------------------
                                         Name:  Lawrence A. Margolis
                                         Title: Executive Vice President and
                                                Chief Financial Officer

                                     BROADBAND PARENT CORPORATION

                                     By:  /s/ Lawrence A. Margolis
                                         ---------------------------------
                                         Name:  Lawrence A. Margolis
                                         Title: Vice President and Secretary

                                     BROADBAND TRANSITION CORPORATION

                                     By:  /s/ Lawrence A. Margolis
                                         ---------------------------------
                                         Name:  Lawrence A. Margolis
                                         Title: Vice President and Secretary

                                     NORTEL NETWORKS INC.

                                     By: /s/ Craig A. Johnson
                                         ---------------------------------
                                         Name:  Craig A. Johnson
                                         Title:

                                     NORTEL NETWORKS LLC

                                     By: /s/ Craig A. Johnson
                                         ---------------------------------
                                         Name:  Craig A. Johnson
                                         Title:

                                     ARRIS INTERACTIVE L.L.C.

                                     By: /s/ David B. Potts
                                         ---------------------------------
                                         Name:  David B. Potts
                                         Title: Vice President and Chief
                                                Financial Officer


                                       4