Patent ID: 8750122
Filing Date: 2014-06-10
Classification: H04L

Abstract:
1. A method of layer 2 loop prevention in a multi-node switch cluster, the method comprising the steps of: associating, by a first node of the multi-node switch cluster, a LAG/MLT ID with each LAG/MLT port on the first node that connects to a link extending between the first node and a third node; associating, by a second node of the multi-node switch cluster, the LAG/MLT ID with each LAG/MLT port on the second node that connects to a link extending between the second node and the third node; receiving a broadcast packet associated with a VLAN on one of the LAG/MLT ports on the first node; tagging at least one copy of the broadcast packet with the LAG/MLT ID; transmitting copies of the broadcast packet on all user ports on the first node associated with the VLAN except ports associated with the LAG/MLT ID; transmitting the tagged copy of the broadcast packet on an inter-switch trunk to the second node of the multi-node switch cluster; wherein the first node maintains only one MGID per VLAN, the only one MGID being a bitmap applied by the first node to the broadcast packet and identifying a set of output ports for the VLAN at the first node, the only one MGID being used by the first node to forward broadcast packets associated with the VLAN received on the LAG/MLT ports as well as to forward broadcast packets associated with the VLAN received on the inter-switch trunk; and wherein the MGID is used only within the first node and is removed by the first node prior to forwarding broadcast packets on the inter-switch trunk.