US Patent No. 9,942,149

SYSTEM AND METHOD OF USING AN EXACT MATCH TABLE AND LONGEST PREFIX MATCH TABLE AS A COMBINED LONGEST PREFIX MATCH


Patent No. 9,942,149
Issue Date April 10, 2018
Title System And Method Of Using An Exact Match Table And Longest Prefix Match Table As A Combined Longest Prefix Match
Inventorship Francois Labonte, Menlo Park, CA (US)
Hugh W. Holbrook, Palo Alto, CA (US)
Assignee Arista Networks, Inc., Santa Clara, CA (US)

Claim of US Patent No. 9,942,149

1. A non-transitory machine-readable medium having executable instructions to cause one or more processing units to perform a method to determine a match for a destination address using an exact match table and a longest prefix match table, the method comprising:receiving, with a network element, a data packet that includes a destination address;
generating a lookup key for the destination address, wherein the lookup key represents more addresses than the destination address;
performing an exact match table address lookup using the lookup key with an exact match table, wherein a first forwarding result is derived from a match in the exact match table address lookup and at least one of the entries in the exact match table includes,
an exact match table key, and
a plurality of forwarding indications, wherein each of the plurality of forwarding indications is associated with one of a plurality of prefixes associated with the exact match table key;
performing a longest prefix match address lookup using the destination address with the longest prefix match table, wherein a second forwarding result is derived from a match of the longest prefix match address lookup and at least some of content in the lookup key overlaps with content used for the longest prefix match address lookup;
determining a resolved forwarding result based on results from the exact match table address lookup and the longest prefix match address lookup; and
forwarding the data packet using the resolved forwarding result.