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                                                                    EXHIBIT 10.1


                          LOAN MODIFICATION AGREEMENT


      This Loan Modification Agreement is entered into as of May 4, 1999, by
and between MMC Networks, Inc. ("Borrower") and Silicon Valley Bank ("Bank").

1.    DESCRIPTION OF EXISTING INDEBTEDNESS. Among other indebtedness which may
be owing by Borrower to Bank, Borrower is indebted to Bank pursuant to, among
other documents, a Loan Agreement, dated May 7, 1998, as may be amended from
time to time, (the "Loan Agreement"). The Loan Agreement provided for, among
other things, a Committed Line in the original principal amount of Eight
Million Dollars ($8,000,000) (the "Revolving Facility"). Defined terms used but
not otherwise defined herein shall have the same meanings as in the Loan
Agreement.

Hereinafter, all Indebtedness owing by Borrower to Bank shall be referred to as
the "Indebtedness."

Hereinafter, all documents evidencing the Indebtedness shall be referred to as
the "Existing Loan Documents."

2.    DESCRIPTION OF CHANGE IN TERMS.

      A.    Modification(s) to Loan Agreement

            1.    The defined term "Revolving Maturity Date" in Section 12.1
                  entitled "Definitions" is hereby amended to read May 6, 2000.

4.    CONSISTENT CHANGES. The Existing Loan Documents are hereby amended
wherever necessary to reflect the changes described above.

5.    NO DEFENSES OF BORROWER. Borrower (and each guarantor and pledgor signing
below) agrees that, as of the date hereof, it has no defenses against the
obligations to pay any amounts under the Indebtedness.

6.    CONTINUING VALIDITY. Borrower (and each guarantor and pledgor signing
below) understands and agrees that in modifying the existing Indebtedness, Bank
is relying upon Borrower's representations, warranties, and agreements, as set
forth in the Existing Loan Documents. Except as expressly modified pursuant to
this Loan Modification Agreement, the terms of the Existing Loan Documents
remain unchanged and in full force and effect. Bank's agreement to
modifications to the existing Indebtedness pursuant to this Loan Modification
Agreement in no way shall obligate Bank to make any future modifications to the
Indebtedness. Nothing in this Loan Modification Agreement shall constitute a
satisfaction of the Indebtedness. It is the intention of Bank and Borrower to
retain as liable parties all makers and endorsers of Existing Loan Documents,
unless the party is expressly released by Bank in writing. No maker, endorser,
or guarantor will be released by virtue of this Loan Modification Agreement.
The terms of this paragraph apply not only to this Loan Modification Agreement,
but also to all subsequent loan modification agreements.

      This Loan Modification Agreement is executed as of the date first written
above.


BORROWER:                                 BANK:

MMC NETWORKS, INC.                        SILICON VALLEY BANK

By:   /s/ Uday Bellary                    By:   /s/ Peter R. Scott
   ------------------------------            ------------------------------
Name:  Uday Bellary                       Name:  Peter R. Scott
     ----------------------------              ----------------------------
Title: VP of Finance, CFO                 Title: Vice President
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