content: <PAGE>   1
  
  
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JANUARY 29, 1997.
                                                         REGISTRATION NO. 333-____
  
  ================================================================================
  
                         SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON, D.C. 20549
  
                                      FORM S-8
  
                            REGISTRATION STATEMENT UNDER
                             THE SECURITIES ACT OF 1933
  
                            CASCADE COMMUNICATIONS CORP.
               (Exact Name of Registrant as Specified in Its Charter)
  
               DELAWARE                                    04-3099677
   (State or Other Jurisdiction of            (I.R.S. Employer Identification No.)
    Incorporation or Organization)
  
                                   5 CARLISLE ROAD
                         WESTFORD, MASSACHUSETTS 01886-3601
                      (Address of Principal Executive Offices)
  
                                --------------------
  
                        SAHARA NETWORKS, INC. 1995 STOCK PLAN
                              (Full Title of the Plan)
  
                                --------------------
  
                                   DANIEL E. SMITH
                        PRESIDENT AND CHIEF EXECUTIVE OFFICER
  
                            CASCADE COMMUNICATIONS CORP.
                                   5 CARLISLE ROAD
                         WESTFORD, MASSACHUSETTS 01886-3601
                       (Name and Address of Agent For Service)
  
                                   (508) 692-2600
            (Telephone Number, Including Area Code, of Agent For Service)
  
                                --------------------
  
                                     Copies to:
  
                                JOHN A. MELTAUS, ESQ.
                           Testa, Hurwitz & Thibeault, LLP
                                  High Street Tower
                                   125 High Street
                             Boston, Massachusetts 02110
                                   (617) 248-7000
  
  ================================================================================
  
  
  <PAGE>   2
  
  
  
  
  
  <TABLE>
  ====================================================================================================================
  
                                            CALCULATION OF REGISTRATION FEE
  
  ====================================================================================================================
  <CAPTION>
  
  
  
                                                         PROPOSED              PROPOSED 
                                                         MAXIMUM                MAXIMUM
    TITLE OF SECURITIES           AMOUNT TO BE        OFFERING PRICE           AGGREGATE                AMOUNT OF 
     TO BE REGISTERED              REGISTERED          PER SHARE(1)          OFFERING PRICE        REGISTRATION FEE(2)
    -------------------           ------------        --------------         --------------        -------------------
  <S>                               <C>                                       <C>                        <C>    
  Cascade Communications
  Corp.                             276,763               $0.05               $ 13,838.15
  Common Stock,                      99,708               $0.98                 97,713.84
  $.001 par value                    14,295               $1.96                 28,018.20
  
  
              TOTAL:                390,766 shares                            $139,570.19                $100.00
  
  ====================================================================================================================
  <FN>
  
          (1)   Based on options to purchase 390,766 shares of Common Stock, $.001 par value (the "Common Stock"), of
          Cascade Communications Corp. outstanding as of January 28, 1997 under the Sahara Networks, Inc. 1995 Stock 
          Plan. All of such shares are issuable upon exercise of outstanding options with fixed exercise prices. 
          Pursuant to Rule 457(h)(1) of Regulation C under the Securities Act of 1933, as amended (the "Securities 
          Act"), the aggregate offering price has been computed upon the basis of the price at which the options may 
          be exercised.
  
          (2)   Calculated pursuant to Section 6(b) of the Securities Act.
  </TABLE>
  
           This Registration Statement covers an aggregate of 390,766 shares of
  Common Stock of Cascade Communications Corp. ("Cascade" or the "Company")
  issuable upon exercise of options granted pursuant to the 1995 Stock Plan (the
  "Stock Plan") of Sahara Networks, Inc. ("Sahara"). Sahara was acquired by
  Cascade on January 28, 1997 pursuant to an Agreement and Plan of Merger and
  Reorganization dated January 2, 1997 (the "Merger Agreement"). Pursuant to the
  terms of the Merger Agreement, Cascade assumed all of the then outstanding
  options granted under the Stock Plan to purchase an aggregate of 1,913,500
  shares of common stock, $.01 par value, of Sahara which are convertible into an
  aggregate of 390,766 shares of Cascade Common Stock, assuming the exercise of
  all outstanding options. No additional options or other rights will be granted
  by Cascade under such plan.
  
  
  
                                        - 2 -
  <PAGE>   3
  
                                       PART I
  
                INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS
  
  
  ITEM 1.  PLAN INFORMATION.
           ----------------
  
        The documents containing the information specified in this Item 1 will be
  sent or given to employees, directors or others as specified by Rule 428(b)(1).
  In accordance with the rules and regulations of the Securities and Exchange
  Commission (the "Commission") and the instructions to Form S-8, such documents
  are not being filed with the Commission either as part of this Registration
  Statement or as prospectuses or prospectus supplements pursuant to Rule 424.
  
  ITEM 2.  REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.
           -----------------------------------------------------------
  
        The documents containing the information specified in this Item 2 will be
  sent or given to employees as specified by Rule 428(b)(1). In accordance with
  the rules and regulations of the Commission and the instructions to Form S-8,
  such documents are not being filed with the Commission either as part of this
  Registration Statement or as prospectuses or prospectus supplements pursuant to
  Rule 424.
  
  
                                       PART II
  
                 INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.
           ---------------------------------------
  
        The following documents filed with the Commission are incorporated by
  reference in this Registration Statement:
  
        (a)     The Registrant's Annual Report on Form 10-K for the fiscal year 
                ended December 31, 1995.
  
        (b)     The Registrant's Quarterly Report on Form 10-Q for the quarter 
                ended March 30, 1996.
  
        (c)     The Registrant's Quarterly Report on Form 10-Q for the quarter 
                ended June 29, 1996.
  
        (d)     The Registrant's Quarterly Report on Form 10-Q for the quarter 
                ended September 28, 1996.
  
        (e)     The Company's Current Reports on Form 8-K dated February 27, 1996,
                May 3, 1996, May 30, 1996, July 11, 1996, and January 16, 1997.
  
        (f)     The description of the Company's Common Stock, $.001 par value per
                share, contained in Cascade's Registration Statement on Form 8-A
                filed pursuant to Section 12(g) of the Securities Exchange Act of
                1934, as amended (the "Exchange Act"), on July 26, 1994.
  
        All documents subsequently filed with the Commission by the Registrant
  pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to
  the filing of a post-effective amendment which indicates that all securities
  offered herein have been sold or which deregisters all securities then 
  
  
                                        -3-
  <PAGE>   4
  
  
  remaining unsold, shall be deemed to be incorporated by reference in this
  Registration Statement and to be a part hereof from the date of filing of such
  documents.
  
  ITEM 4.  DESCRIPTION OF SECURITIES.
           -------------------------
  
        Not applicable.
  
  ITEM 5.  INTEREST OF NAMED EXPERTS AND COUNSEL.
           -------------------------------------
  
        Not applicable.
  
  ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.
           -----------------------------------------
  
        Article EIGHT of the Registrant's Amended and Restated Certificate of
  Incorporation provides that no director of the Registrant shall be personally
  liable to the Registrant or its stockholders for monetary damages for breach of
  fiduciary duty as a director notwithstanding any provision of law imposing such
  liability, except, to the extent provided by applicable law (i) for any breach
  of the director's duty of loyalty to the Registrant or its stockholders, (ii)
  for acts or omissions not in good faith or which involve intentional misconduct
  or a knowing violation of law, (iii) under Section 174 of the General
  Corporation Law of the State of Delaware, or (iv) for any transaction from which
  the director derived an improper personal benefit. If the General Corporation
  Law of the State of Delaware is amended hereafter to authorize corporation
  action further eliminating or limiting the personal liability of directors, then
  the liability of a director of the Registrant shall be eliminated or limited to
  the fullest extent permitted by the General Corporation Law of the State of
  Delaware, as so amended. No amendment or repeal of Article EIGHT shall apply to
  have any effect on the liability or alleged liability of any director for or
  with respect to any acts or omissions of such director occurring prior to such
  amendment or repeal.
  
        Article TENTH of the Registrant's Amended and Restated Certificate of
  Incorporation provides that the Registrant shall, to the maximum extent
  permitted from time to time under the laws of the State of Delaware, indemnify
  and upon request shall advance expenses to any person who is or was a party or
  is threatened to be made a party to any threatened, pending or completed action,
  suit, proceeding or claim, whether civil, criminal, administrative or
  investigative, by reason of the fact that he is or was or has agreed to be a
  director or officer of the Registrant or while a director or officer is or was
  serving at the request of the Registrant as a director, officer, partner,
  trustee, employee or agent of any corporation, partnership, joint venture, trust
  or other enterprise, including service with respect to employee benefit plans,
  against any and all expenses (including attorney's fees and expenses),
  judgments, fines, penalties and amounts paid in settlement or incurred in
  connection with the investigation, preparation to defend or defense of such
  action, suit, proceeding or claim; PROVIDED, HOWEVER, that the foregoing shall
  not require the Registrant to indemnify or advance expenses to any person in
  connection with any action, suit, proceeding, claim or counterclaim initiated by
  or on behalf of such person. Such indemnification shall not be exclusive of
  other indemnification rights arising under any by-law, agreement, vote of
  directors or stockholders or otherwise and shall inure to the benefit of the
  heirs and legal representatives of such person. Any repeal or modification of
  Article TENTH shall not adversely affect any right or protection of a director
  or officer of the Registrant existing at the time of such repeal or
  modification.
  
        Article ELEVENTH of the Registrant's Amended and Restated Certificate of
  Incorporation further provides that in addition to the vote of the holders of
  any class or series of stock of the Registrant required by law or by the Amended
  and Restated Certificate of Incorporation, but in addition to any vote of the
  holders of any class or series of stock of the Corporation required by law, the
  Amended and 
  
  
                                        -4-
  <PAGE>   5
  
  
  Restated Certificate of Incorporation or a Certificate of Designation with
  respect to a series of Preferred Stock, the affirmative vote of the holders of
  shares of voting stock of the Registrant representing at least seventy-five
  percent (75%) of the voting power of all of the then outstanding shares of the
  capital stock of the Registrant entitled to vote generally in the election of
  directors, voting together as a single class, shall be required to amend or
  repeal, or adopt any provision inconsistent with Article EIGHTH, TENTH or
  ELEVENTH of the Amended and Restated Certificate of Incorporation.
  
        The Company has obtained directors and officers liability insurance for
  the benefit of its directors and certain of its officers.
  
  ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.
           -----------------------------------
  
        Not applicable.
  
  <TABLE>
  ITEM 8.  EXHIBITS
           --------
  <CAPTION>
  
         Exhibit
         Number                    Description of Exhibit
         -------                   ----------------------
  
         <S>                       <C>
         Exhibit 4.1*              Amended and Restated Certificate of Incorporation of the Registrant (filed as
                                   Exhibit 3.1 to the Registrant's Registration Statement on Form S-1 (File No.
                                   33-79330) and incorporated herein by reference).
  
         Exhibit 4.2*              Certificate of Amendment of Amended and Restated Certificate of Incorporation of
                                   the Registrant (filed as Exhibit 4.2 to the Registrant's Registration Statement on
                                   Form S-8 (File No. 333-06417) and incorporated herein by reference).
  
         Exhibit 4.3*              Amended and Restated By-laws of the Registrant (filed as Exhibit 3.2 to the
                                   Registrant's Registration Statement on Form S-1 (File No. 33-79330) and
                                   incorporated herein by reference).
  
         Exhibit 4.4*              Specimen stock certificate representing the Common Stock of the Registrant (filed
                                   as Exhibit 4.1 to the Registrant's Registration Statement on Form S-1 (File No.
                                   33-79330) and incorporated herein by reference).
  
         Exhibit 4.5               Sahara Networks, Inc. 1995 Stock Plan.
  
         Exhibit 5.1               Opinion of Testa, Hurwitz & Thibeault, LLP.
  
         Exhibit 23.1              Consent of Testa, Hurwitz & Thibeault, LLP (included in Exhibit 5.1).
  
         Exhibit 23.2              Consent of Coopers & Lybrand L.L.P.
  
         Exhibit 24.1              Power of Attorney (found on page 8 of this Registration Statement).
  <FN>
  
         ---------------
         *Previously filed
  </TABLE>
  
  
                                        -5-
  <PAGE>   6
  
  Item 9.  Undertakings.
           ------------
  
        (a)     The undersigned Registrant hereby undertakes:
  
                (1)    To file, during any period in which offers or sales are
                       being made, a post-effective amendment to this Registration
                       Statement:
  
                        (i)   To include any prospectus required by Section 
                              10(a)(3) of the Securities Act of 1933;
  
                       (ii)   To reflect in the prospectus any facts or events
                              arising after the effective date of the Registration
                              Statement (or the most recent post-effective
                              amendment thereof) which, individually or in the
                              aggregate, represent a fundamental change in the
                              information set forth in the Registration Statement;
                              and
  
                      (iii)   To include any material information with respect to
                              the plan of distribution not previously disclosed in
                              the Registration Statement or any material change to
                              such information in the Registration Statement;
  
                       PROVIDED, HOWEVER, that paragraphs (a)(1)(i) and (a)(1)(ii)
                       do not apply if the information required to be included in
                       a post-effective amendment by those paragraphs is contained
                       in periodic reports filed with or furnished to the
                       Commission by the Registrant pursuant to Section 13 or
                       Section 15(d) of the Securities Exchange Act of 1934 that
                       are incorporated by reference in the Registration
                       Statement.
  
                (2)    That, for the purpose of determining any liability under
                       the Securities Act of 1933, each such post-effective
                       amendment shall be deemed to be a new registration
                       statement relating to the securities offered therein, and
                       the offering of such securities at that time shall be
                       deemed to be the initial bona fide offering thereof.
  
                (3)    To remove from registration by means of a post-effective
                       amendment any of the securities being registered which
                       remain unsold at the termination of the offering.
  
        (b)     The undersigned Registrant hereby undertakes that, for purposes of
  determining any liability under the Securities Act of 1933, each filing of the
  Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
  Securities Exchange Act of 1934 (and, where applicable, each filing of an
  employee benefit plan's annual report pursuant to Section 15(d) of the
  Securities Exchange Act of 1934) that is incorporated by reference in the
  Registration Statement shall be deemed to be a new registration statement
  relating to the securities offered therein, and the offering of such securities
  at that time shall be deemed to be the initial bona fide offering thereof.
  
        (c)     Insofar as indemnification for liabilities arising under the
  Securities Act of 1933 may be permitted to directors, officers and controlling
  persons of the Registrant pursuant to the foregoing provisions, or otherwise,
  the Registrant has been advised that in the opinion of the Securities and
  Exchange Commission such indemnification is against public policy as expressed
  in the Act and is, therefore, unenforceable. In the event that a claim for
  indemnification against such liabilities (other than the payment by the
  Registrant of expenses incurred or paid by a director, officer or controlling
  person of the Registrant in the successful defense of any action, suit or
  proceeding) is asserted by such director, officer or controlling person in
  connection with the securities being registered, the Registrant will, unless 
  
  
                                        -6-
  <PAGE>   7
  
  
  in the opinion of its counsel the matter has been settled by controlling
  precedent, submit to a court of appropriate jurisdiction the question whether
  such indemnification by it is against public policy as expressed in the Act and
  will be governed by the final adjudication of such issue.
  
  
                                        -7-
  <PAGE>   8
  
  
  
                                     SIGNATURES
  
        Pursuant to the requirements of the Securities Act of 1933, the
  Registrant, Cascade Communications Corp., certifies that it has reasonable
  grounds to believe that it meets all of the requirements for filing on Form S-8
  and has duly caused this Registration Statement to be signed on its behalf by
  the undersigned, thereunto duly authorized, in the Westford, Commonwealth of
  Massachusetts on this 29th day of January, 1997.
  
                                        CASCADE COMMUNICATIONS CORP.
  
  
                                        By:  /s/ Daniel E. Smith
                                            -------------------------------------
                                            Daniel E. Smith
                                            President and Chief Executive Officer
  
                                  POWER OF ATTORNEY
  
        KNOW ALL PERSONS BY THESE PRESENTS, that each such person whose signature
  appears below constitutes and appoints, jointly and severally, Daniel E. Smith,
  Paul E. Blondin and Frances M. Jewels his or her attorneys-in-fact, each with
  the power of substitutions, for him or her in any and all capacities, to sign
  any amendments to this Registration Statement on Form S-8 (including any
  post-effective amendments), and to file the same, with all exhibits thereto, and
  other documents in connection therewith, with the Securities and Exchange
  Commission, hereby ratifying and confirming all that each of said
  attorneys-in-fact, or his or her substitute or substitutes, may do or cause to
  be done by virtue hereof.
  
        Pursuant to the requirements of the Securities Act of 1933, this
  Registration Statement has been signed by the following persons in the
  capacities and on the dates indicated.
  
  
  <TABLE>
  <CAPTION>
        SIGNATURE                            TITLE                       DATE
        ---------                            -----                       ----
  <S>                         <C>                                  <C> 
  /s/ Daniel E. Smith         President, Chief Executive Officer   January 29, 1997
  -------------------------   and Director
  Daniel E. Smith
  
  /s/ Paul E. Blondin         Vice President of Finance and        January 29, 1997
  -------------------------   Administration, and Chief Financial
  Paul E. Blondin             Officer, Treasurer and Secretary
                              (Principle Financial and Accounting
                              Officer)
  
  /s/ Victoria A. Brown       Director                             January 29, 1997
  -------------------------
  Victoria A. Brown
  
  /s/ Gururaj Deshpande       Director                             January 29, 1997
  -------------------------
  Gururaj Deshpande
  
  /s/ Richard M. Burnes, Jr.  Director                             January 29, 1997
  --------------------------
  Richard M. Burnes, Jr.
  </TABLE>
  
                                        -8-
  <PAGE>   9
  
  
  /s/ Bruns H. Grayson        Director                     January 29, 1997
  -------------------------
  Bruns H. Grayson
  
  /s/ Paul J. Ferri           Director                     January 29, 1997
  -------------------------
  Paul J. Ferri
  
  /s/ Steven Walske           Director                     January 29, 1997
  -------------------------
  Steven Walske
  
  
  
  <PAGE>   10
  
  <TABLE>
                                            INDEX TO EXHIBITS
  <CAPTION>
  
  
     Exhibit                                                                            Sequentially 
     Number                                      Exhibit                                Numbered Page
     ------                                      -------                                -------------
  
  <S>                  <C>
  Exhibit 4.1*         Amended and Restated Certificate of Incorporation of the 
                       Registrant (filed as Exhibit 3.1 to the Registrant's 
                       Registration Statement on Form S-1 (File No. 33-79330) and 
                       incorporated herein by reference).
  
  Exhibit 4.2*         Certificate of Amendment of Amended and Restated
                       Certificate of Incorporation of the Registrant (filed as
                       Exhibit 4.2 to the Registrant's Registration Statement on
                       Form S-8 (File No. 333-06417) and incorporated herein by
                       reference).
  
  Exhibit 4.3*         Amended and Restated By-laws of the Registrant (filed as 
                       Exhibit 3.2 to the Registrant's Registration Statement on 
                       Form S-1 (File No. 33-79330) and incorporated herein by 
                       reference).
  
  Exhibit 4.4*         Specimen stock certificate representing the Common
                       Stock of the Registrant (filed as Exhibit 4.1 to the
                       Registrant's Registration Statement on Form S-1 (File No.
                       33-79330) and incorporated herein by reference).
  
  Exhibit 4.5          Sahara Networks, Inc. 1995 Stock Plan.
  
  Exhibit 5.1          Opinion of Testa, Hurwitz & Thibeault, LLP.
  
  Exhibit 23.1         Consent of Testa, Hurwitz & Thibeault, LLP (included in 
                       Exhibit 5.1).
  
  Exhibit 23.2         Consent of Coopers & Lybrand L.L.P.
  
  Exhibit 24.1         Power of Attorney (found on page 8 of this Registration 
                       Statement).
  <FN>
  
  -----------
  *Previously filed
  </TABLE>
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metadata_filer: {"company-data": {"conformed-name": "CASCADE COMMUNICATIONS CORP", "cik": "0000887763", "assigned-sic": "3576", "irs-number": "043099677", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-20659", "film-number": "97513701"}, "business-address": {"street1": "5 CARLISLE RD", "city": "WESTFORD", "state": "MA", "zip": "01886", "phone": "8006922401"}, "mail-address": {"street1": "5 CARLISLE ROAD", "city": "WESTORD", "state": "MA", "zip": "01886"}}
text: 1
  
     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JANUARY 29, 1997.
                                                         REGISTRATION NO. 333-____
  
  ================================================================================
  
                         SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON, D.C. 20549
  
                                      FORM S-8
  
                            REGISTRATION STATEMENT UNDER
                             THE SECURITIES ACT OF 1933
  
                            CASCADE COMMUNICATIONS CORP.
               (Exact Name of Registrant as Specified in Its Charter)
  
               DELAWARE                                    04-3099677
   (State or Other Jurisdiction of            (I.R.S. Employer Identification No.)
    Incorporation or Organization)
  
                                   5 CARLISLE ROAD
                         WESTFORD, MASSACHUSETTS 01886-3601
                      (Address of Principal Executive Offices)
  
                                --------------------
  
                        SAHARA NETWORKS, INC. 1995 STOCK PLAN
                              (Full Title of the Plan)
  
                                --------------------
  
                                   DANIEL E. SMITH
                        PRESIDENT AND CHIEF EXECUTIVE OFFICER
  
                            CASCADE COMMUNICATIONS CORP.
                                   5 CARLISLE ROAD
                         WESTFORD, MASSACHUSETTS 01886-3601
                       (Name and Address of Agent For Service)
  
                                   (508) 692-2600
            (Telephone Number, Including Area Code, of Agent For Service)
  
                                --------------------
  
                                     Copies to:
  
                                JOHN A. MELTAUS, ESQ.
                           Testa, Hurwitz & Thibeault, LLP
                                  High Street Tower
                                   125 High Street
                             Boston, Massachusetts 02110
                                   (617) 248-7000
  
  ================================================================================
  2
  
  ====================================================================================================================
  
                                            CALCULATION OF REGISTRATION FEE
  
  ====================================================================================================================
  PROPOSED              PROPOSED 
                                                         MAXIMUM                MAXIMUM
    TITLE OF SECURITIES           AMOUNT TO BE        OFFERING PRICE           AGGREGATE                AMOUNT OF 
     TO BE REGISTERED              REGISTERED          PER SHARE(1)          OFFERING PRICE        REGISTRATION FEE(2)
    -------------------           ------------        --------------         --------------        -------------------
  Cascade Communications
  Corp.                             276,763               $0.05               $ 13,838.15
  Common Stock,                      99,708               $0.98                 97,713.84
  $.001 par value                    14,295               $1.96                 28,018.20
  
              TOTAL:                390,766 shares                            $139,570.19                $100.00
  
  ====================================================================================================================
  (1)   Based on options to purchase 390,766 shares of Common Stock, $.001 par value (the "Common Stock"), of
          Cascade Communications Corp. outstanding as of January 28, 1997 under the Sahara Networks, Inc. 1995 Stock 
          Plan. All of such shares are issuable upon exercise of outstanding options with fixed exercise prices. 
          Pursuant to Rule 457(h)(1) of Regulation C under the Securities Act of 1933, as amended (the "Securities 
          Act"), the aggregate offering price has been computed upon the basis of the price at which the options may 
          be exercised.
  
          (2)   Calculated pursuant to Section 6(b) of the Securities Act.
  This Registration Statement covers an aggregate of 390,766 shares of
  Common Stock of Cascade Communications Corp. ("Cascade" or the "Company")
  issuable upon exercise of options granted pursuant to the 1995 Stock Plan (the
  "Stock Plan") of Sahara Networks, Inc. ("Sahara"). Sahara was acquired by
  Cascade on January 28, 1997 pursuant to an Agreement and Plan of Merger and
  Reorganization dated January 2, 1997 (the "Merger Agreement"). Pursuant to the
  terms of the Merger Agreement, Cascade assumed all of the then outstanding
  options granted under the Stock Plan to purchase an aggregate of 1,913,500
  shares of common stock, $.01 par value, of Sahara which are convertible into an
  aggregate of 390,766 shares of Cascade Common Stock, assuming the exercise of
  all outstanding options. No additional options or other rights will be granted
  by Cascade under such plan.
  
                                        - 2 -
  3
  
                                       PART I
  
                INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS
  
  ITEM 1.  PLAN INFORMATION.
           ----------------
  
        The documents containing the information specified in this Item 1 will be
  sent or given to employees, directors or others as specified by Rule 428(b)(1).
  In accordance with the rules and regulations of the Securities and Exchange
  Commission (the "Commission") and the instructions to Form S-8, such documents
  are not being filed with the Commission either as part of this Registration
  Statement or as prospectuses or prospectus supplements pursuant to Rule 424.
  
  ITEM 2.  REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.
           -----------------------------------------------------------
  
        The documents containing the information specified in this Item 2 will be
  sent or given to employees as specified by Rule 428(b)(1). In accordance with
  the rules and regulations of the Commission and the instructions to Form S-8,
  such documents are not being filed with the Commission either as part of this
  Registration Statement or as prospectuses or prospectus supplements pursuant to
  Rule 424.
  
                                       PART II
  
                 INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.
           ---------------------------------------
  
        The following documents filed with the Commission are incorporated by
  reference in this Registration Statement:
  
        (a)     The Registrant's Annual Report on Form 10-K for the fiscal year 
                ended December 31, 1995.
  
        (b)     The Registrant's Quarterly Report on Form 10-Q for the quarter 
                ended March 30, 1996.
  
        (c)     The Registrant's Quarterly Report on Form 10-Q for the quarter 
                ended June 29, 1996.
  
        (d)     The Registrant's Quarterly Report on Form 10-Q for the quarter 
                ended September 28, 1996.
  
        (e)     The Company's Current Reports on Form 8-K dated February 27, 1996,
                May 3, 1996, May 30, 1996, July 11, 1996, and January 16, 1997.
  
        (f)     The description of the Company's Common Stock, $.001 par value per
                share, contained in Cascade's Registration Statement on Form 8-A
                filed pursuant to Section 12(g) of the Securities Exchange Act of
                1934, as amended (the "Exchange Act"), on July 26, 1994.
  
        All documents subsequently filed with the Commission by the Registrant
  pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to
  the filing of a post-effective amendment which indicates that all securities
  offered herein have been sold or which deregisters all securities then 
  
                                        -3-
  4
  
  remaining unsold, shall be deemed to be incorporated by reference in this
  Registration Statement and to be a part hereof from the date of filing of such
  documents.
  
  ITEM 4.  DESCRIPTION OF SECURITIES.
           -------------------------
  
        Not applicable.
  
  ITEM 5.  INTEREST OF NAMED EXPERTS AND COUNSEL.
           -------------------------------------
  
        Not applicable.
  
  ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.
           -----------------------------------------
  
        Article EIGHT of the Registrant's Amended and Restated Certificate of
  Incorporation provides that no director of the Registrant shall be personally
  liable to the Registrant or its stockholders for monetary damages for breach of
  fiduciary duty as a director notwithstanding any provision of law imposing such
  liability, except, to the extent provided by applicable law (i) for any breach
  of the director's duty of loyalty to the Registrant or its stockholders, (ii)
  for acts or omissions not in good faith or which involve intentional misconduct
  or a knowing violation of law, (iii) under Section 174 of the General
  Corporation Law of the State of Delaware, or (iv) for any transaction from which
  the director derived an improper personal benefit. If the General Corporation
  Law of the State of Delaware is amended hereafter to authorize corporation
  action further eliminating or limiting the personal liability of directors, then
  the liability of a director of the Registrant shall be eliminated or limited to
  the fullest extent permitted by the General Corporation Law of the State of
  Delaware, as so amended. No amendment or repeal of Article EIGHT shall apply to
  have any effect on the liability or alleged liability of any director for or
  with respect to any acts or omissions of such director occurring prior to such
  amendment or repeal.
  
        Article TENTH of the Registrant's Amended and Restated Certificate of
  Incorporation provides that the Registrant shall, to the maximum extent
  permitted from time to time under the laws of the State of Delaware, indemnify
  and upon request shall advance expenses to any person who is or was a party or
  is threatened to be made a party to any threatened, pending or completed action,
  suit, proceeding or claim, whether civil, criminal, administrative or
  investigative, by reason of the fact that he is or was or has agreed to be a
  director or officer of the Registrant or while a director or officer is or was
  serving at the request of the Registrant as a director, officer, partner,
  trustee, employee or agent of any corporation, partnership, joint venture, trust
  or other enterprise, including service with respect to employee benefit plans,
  against any and all expenses (including attorney's fees and expenses),
  judgments, fines, penalties and amounts paid in settlement or incurred in
  connection with the investigation, preparation to defend or defense of such
  action, suit, proceeding or claim; PROVIDED, HOWEVER, that the foregoing shall
  not require the Registrant to indemnify or advance expenses to any person in
  connection with any action, suit, proceeding, claim or counterclaim initiated by
  or on behalf of such person. Such indemnification shall not be exclusive of
  other indemnification rights arising under any by-law, agreement, vote of
  directors or stockholders or otherwise and shall inure to the benefit of the
  heirs and legal representatives of such person. Any repeal or modification of
  Article TENTH shall not adversely affect any right or protection of a director
  or officer of the Registrant existing at the time of such repeal or
  modification.
  
        Article ELEVENTH of the Registrant's Amended and Restated Certificate of
  Incorporation further provides that in addition to the vote of the holders of
  any class or series of stock of the Registrant required by law or by the Amended
  and Restated Certificate of Incorporation, but in addition to any vote of the
  holders of any class or series of stock of the Corporation required by law, the
  Amended and 
  
                                        -4-
  5
  
  Restated Certificate of Incorporation or a Certificate of Designation with
  respect to a series of Preferred Stock, the affirmative vote of the holders of
  shares of voting stock of the Registrant representing at least seventy-five
  percent (75%) of the voting power of all of the then outstanding shares of the
  capital stock of the Registrant entitled to vote generally in the election of
  directors, voting together as a single class, shall be required to amend or
  repeal, or adopt any provision inconsistent with Article EIGHTH, TENTH or
  ELEVENTH of the Amended and Restated Certificate of Incorporation.
  
        The Company has obtained directors and officers liability insurance for
  the benefit of its directors and certain of its officers.
  
  ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.
           -----------------------------------
  
        Not applicable.
  
  ITEM 8.  EXHIBITS
           --------
  Exhibit
         Number                    Description of Exhibit
         -------                   ----------------------
  Exhibit 4.1*              Amended and Restated Certificate of Incorporation of the Registrant (filed as
                                   Exhibit 3.1 to the Registrant's Registration Statement on Form S-1 (File No.
                                   33-79330) and incorporated herein by reference).
  
         Exhibit 4.2*              Certificate of Amendment of Amended and Restated Certificate of Incorporation of
                                   the Registrant (filed as Exhibit 4.2 to the Registrant's Registration Statement on
                                   Form S-8 (File No. 333-06417) and incorporated herein by reference).
  
         Exhibit 4.3*              Amended and Restated By-laws of the Registrant (filed as Exhibit 3.2 to the
                                   Registrant's Registration Statement on Form S-1 (File No. 33-79330) and
                                   incorporated herein by reference).
  
         Exhibit 4.4*              Specimen stock certificate representing the Common Stock of the Registrant (filed
                                   as Exhibit 4.1 to the Registrant's Registration Statement on Form S-1 (File No.
                                   33-79330) and incorporated herein by reference).
  
         Exhibit 4.5               Sahara Networks, Inc. 1995 Stock Plan.
  
         Exhibit 5.1               Opinion of Testa, Hurwitz & Thibeault, LLP.
  
         Exhibit 23.1              Consent of Testa, Hurwitz & Thibeault, LLP (included in Exhibit 5.1).
  
         Exhibit 23.2              Consent of Coopers & Lybrand L.L.P.
  
         Exhibit 24.1              Power of Attorney (found on page 8 of this Registration Statement).
  ---------------
         *Previously filed
  -5-
  6
  
  Item 9.  Undertakings.
           ------------
  
        (a)     The undersigned Registrant hereby undertakes:
  
                (1)    To file, during any period in which offers or sales are
                       being made, a post-effective amendment to this Registration
                       Statement:
  
                        (i)   To include any prospectus required by Section 
                              10(a)(3) of the Securities Act of 1933;
  
                       (ii)   To reflect in the prospectus any facts or events
                              arising after the effective date of the Registration
                              Statement (or the most recent post-effective
                              amendment thereof) which, individually or in the
                              aggregate, represent a fundamental change in the
                              information set forth in the Registration Statement;
                              and
  
                      (iii)   To include any material information with respect to
                              the plan of distribution not previously disclosed in
                              the Registration Statement or any material change to
                              such information in the Registration Statement;
  
                       PROVIDED, HOWEVER, that paragraphs (a)(1)(i) and (a)(1)(ii)
                       do not apply if the information required to be included in
                       a post-effective amendment by those paragraphs is contained
                       in periodic reports filed with or furnished to the
                       Commission by the Registrant pursuant to Section 13 or
                       Section 15(d) of the Securities Exchange Act of 1934 that
                       are incorporated by reference in the Registration
                       Statement.
  
                (2)    That, for the purpose of determining any liability under
                       the Securities Act of 1933, each such post-effective
                       amendment shall be deemed to be a new registration
                       statement relating to the securities offered therein, and
                       the offering of such securities at that time shall be
                       deemed to be the initial bona fide offering thereof.
  
                (3)    To remove from registration by means of a post-effective
                       amendment any of the securities being registered which
                       remain unsold at the termination of the offering.
  
        (b)     The undersigned Registrant hereby undertakes that, for purposes of
  determining any liability under the Securities Act of 1933, each filing of the
  Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
  Securities Exchange Act of 1934 (and, where applicable, each filing of an
  employee benefit plan's annual report pursuant to Section 15(d) of the
  Securities Exchange Act of 1934) that is incorporated by reference in the
  Registration Statement shall be deemed to be a new registration statement
  relating to the securities offered therein, and the offering of such securities
  at that time shall be deemed to be the initial bona fide offering thereof.
  
        (c)     Insofar as indemnification for liabilities arising under the
  Securities Act of 1933 may be permitted to directors, officers and controlling
  persons of the Registrant pursuant to the foregoing provisions, or otherwise,
  the Registrant has been advised that in the opinion of the Securities and
  Exchange Commission such indemnification is against public policy as expressed
  in the Act and is, therefore, unenforceable. In the event that a claim for
  indemnification against such liabilities (other than the payment by the
  Registrant of expenses incurred or paid by a director, officer or controlling
  person of the Registrant in the successful defense of any action, suit or
  proceeding) is asserted by such director, officer or controlling person in
  connection with the securities being registered, the Registrant will, unless 
  
                                        -6-
  7
  
  in the opinion of its counsel the matter has been settled by controlling
  precedent, submit to a court of appropriate jurisdiction the question whether
  such indemnification by it is against public policy as expressed in the Act and
  will be governed by the final adjudication of such issue.
  
                                        -7-
  8
  
                                     SIGNATURES
  
        Pursuant to the requirements of the Securities Act of 1933, the
  Registrant, Cascade Communications Corp., certifies that it has reasonable
  grounds to believe that it meets all of the requirements for filing on Form S-8
  and has duly caused this Registration Statement to be signed on its behalf by
  the undersigned, thereunto duly authorized, in the Westford, Commonwealth of
  Massachusetts on this 29th day of January, 1997.
  
                                        CASCADE COMMUNICATIONS CORP.
  
                                        By:  /s/ Daniel E. Smith
                                            -------------------------------------
                                            Daniel E. Smith
                                            President and Chief Executive Officer
  
                                  POWER OF ATTORNEY
  
        KNOW ALL PERSONS BY THESE PRESENTS, that each such person whose signature
  appears below constitutes and appoints, jointly and severally, Daniel E. Smith,
  Paul E. Blondin and Frances M. Jewels his or her attorneys-in-fact, each with
  the power of substitutions, for him or her in any and all capacities, to sign
  any amendments to this Registration Statement on Form S-8 (including any
  post-effective amendments), and to file the same, with all exhibits thereto, and
  other documents in connection therewith, with the Securities and Exchange
  Commission, hereby ratifying and confirming all that each of said
  attorneys-in-fact, or his or her substitute or substitutes, may do or cause to
  be done by virtue hereof.
  
        Pursuant to the requirements of the Securities Act of 1933, this
  Registration Statement has been signed by the following persons in the
  capacities and on the dates indicated.
  SIGNATURE                            TITLE                       DATE
        ---------                            -----                       ----
  /s/ Daniel E. Smith         President, Chief Executive Officer   January 29, 1997
  -------------------------   and Director
  Daniel E. Smith
  
  /s/ Paul E. Blondin         Vice President of Finance and        January 29, 1997
  -------------------------   Administration, and Chief Financial
  Paul E. Blondin             Officer, Treasurer and Secretary
                              (Principle Financial and Accounting
                              Officer)
  
  /s/ Victoria A. Brown       Director                             January 29, 1997
  -------------------------
  Victoria A. Brown
  
  /s/ Gururaj Deshpande       Director                             January 29, 1997
  -------------------------
  Gururaj Deshpande
  
  /s/ Richard M. Burnes, Jr.  Director                             January 29, 1997
  --------------------------
  Richard M. Burnes, Jr.
  -8-
  9
  
  /s/ Bruns H. Grayson        Director                     January 29, 1997
  -------------------------
  Bruns H. Grayson
  
  /s/ Paul J. Ferri           Director                     January 29, 1997
  -------------------------
  Paul J. Ferri
  
  /s/ Steven Walske           Director                     January 29, 1997
  -------------------------
  Steven Walske
  10
  
                                            INDEX TO EXHIBITS
  Exhibit                                                                            Sequentially 
     Number                                      Exhibit                                Numbered Page
     ------                                      -------                                -------------
  Exhibit 4.1*         Amended and Restated Certificate of Incorporation of the 
                       Registrant (filed as Exhibit 3.1 to the Registrant's 
                       Registration Statement on Form S-1 (File No. 33-79330) and 
                       incorporated herein by reference).
  
  Exhibit 4.2*         Certificate of Amendment of Amended and Restated
                       Certificate of Incorporation of the Registrant (filed as
                       Exhibit 4.2 to the Registrant's Registration Statement on
                       Form S-8 (File No. 333-06417) and incorporated herein by
                       reference).
  
  Exhibit 4.3*         Amended and Restated By-laws of the Registrant (filed as 
                       Exhibit 3.2 to the Registrant's Registration Statement on 
                       Form S-1 (File No. 33-79330) and incorporated herein by 
                       reference).
  
  Exhibit 4.4*         Specimen stock certificate representing the Common
                       Stock of the Registrant (filed as Exhibit 4.1 to the
                       Registrant's Registration Statement on Form S-1 (File No.
                       33-79330) and incorporated herein by reference).
  
  Exhibit 4.5          Sahara Networks, Inc. 1995 Stock Plan.
  
  Exhibit 5.1          Opinion of Testa, Hurwitz & Thibeault, LLP.
  
  Exhibit 23.1         Consent of Testa, Hurwitz & Thibeault, LLP (included in 
                       Exhibit 5.1).
  
  Exhibit 23.2         Consent of Coopers & Lybrand L.L.P.
  
  Exhibit 24.1         Power of Attorney (found on page 8 of this Registration 
                       Statement).
  -----------
  *Previously filed