Chingwei Chang

US Patent:

6807172, Oct 19, 2004

Filed:

Dec 21, 1999

Appl. No.:

09/469459

Inventors:

Herman Levenson - Palo Alto CA
Jonathan Davar - Los Altos Hills CA
Ajit Sanzgiri - Cupertino CA
Thomas J. Edsall - Cupertino CA
Chingwei Chang - Sunnyvale CA
Saravanakumar Rajendran - San Jose CA
Tuan Thanh Nguyen - Milpitas CA
Claudette Lucille Surma - Fremont CA

Assignee:

Cisco Technology, Inc. - San Jose CA

International Classification:

H04L 1228

US Classification:

370389, 370423, 370428, 370432, 370471, 370474

Abstract:

A technique enables learning and switching of frames between line cards that are interconnected by a switch fabric of a distributed network switch. The network switch comprises a router and a plurality of forwarding engines, each having an associated forwarding table. The distributed learning and switching technique configures (i) the router to issue an extra copy of a routed frame to an ingress card having a port attached to the source of the frame; (ii) the router to ensure that the contents of a source index field of the routed frame header indicate that the frame originated from the ingress card; (iii) the router to assert a shortcut bit in the header of the routed frame; (iv) a forwarding engine on an egress card having a port attached to the destination of the frame to generate and issue a media access control notification frame to the ingress card and (v) a forwarding engine on the ingress card to mark an established entry in a layer 2 (L2) portion of its forwarding table as ineligible for normal L2 aging policies.