Alan C Ko

US Patent:

55307035, Jun 25, 1996

Filed:

Sep 23, 1994

Appl. No.:

8/311066

Inventors:

Vince Liu - Saratoga CA
Shirley (Tsyr-Yi) Sun - Sunnyvale CA
Alan Ko - Sunnyvale CA

Assignee:

3Com Corporation - Santa Clara CA

International Classification:

H04L 1246

US Classification:

370 8513

Abstract:

Unneeded broadcast and multicast packets are blocked by a remote access server from pass through on a private or switched circuit communication link to a remote node of an corporate LAN, if they relate to protocols not in use by the remote node, or involve information which the remote node does not need. The remote access server includes logic which automatically learns the protocols which the remote node is relying upon, and configures filtering logic for the multi-destination packets in response to the learned protocols. The server executes a method for managing pass through of multi-destination packets, including (1) learning a protocol used by the remote node in response to a packet transmitted to the network by the remote node; (2) storing an identifier of the learned protocol; (3) identifying a protocol of a multi-destination packet in the network; and (4) selecting multi-destination packets to be forwarded to the remote node in response to the stored identifier of the protocol in use by the remote node, and the identified protocol of the multi-destination packet. In addition, a technique for bypasssing the protocol based filtering includes storing addresses provided by the remote node in a multicast address table of multi-destination packets to be forwarded to the remote node; and selecting multi-destination packets to be forwarded to the remote node if the multi-destination packet has a multicast address in the multicast address table.