Patent ID: 7719959

Claim:
A method comprising: forwarding all traffic received from hosts on a first set of VLANs and accepting all traffic destined to hosts on the first set of VLANs at a first layer 2 switch interface of a switch when a first link is up, with the first layer 2 switch interface coupled to a first layer 2 device interface of a first layer 2 and layer 3 network device by the first link; forwarding all traffic received from hosts on a second set of VLANs and accepting all traffic destined to hosts on the second set of VLANs at a second layer 2 switch interface on the switch when a second link is up, with the second layer 2 switch interface coupled to a first layer 2 device interface of a second layer 2 and layer 3 network device by the second link, where the first layer 2 switch interface is a backup of the second layer 2 switch interface and the second layer 2 switch interface is a backup of the first layer 2 switch interface; forwarding only Internet Group Management Protocol (IGMP) messages received from hosts on the first set of VLANs and blocking all traffic destined to hosts on the first set of VLANs at the second layer 2 switch interface on the switch when the first link is up; forwarding only IGMP messages received from hosts on the second set of VLANs and blocking all traffic destined to hosts on the second set of VLANs at the first layer 2 switch interface of the switch when the second link is up; and enabling the second layer 2 switch interface to forward all traffic received from and accept all traffic destined to the first and second groups of VLANs only if the first link fails.