Ip multicast over multi-chassis trunk

Abstract

In embodiments of the present invention, multicast traffic is simultaneously routed via all switches participating in the trunk (can be referred to as partner switches). A respective partner switch synchronizes the local multicast state information with all other partner switches. For a respective multicast group, a plurality of partner switches can be the part of the corresponding multicast distribution tree and obtain multicast traffic from uplink sources. For the multicast group, only one partner switch is elected as the primary forwarder which forwards the multicast traffic via the trunk. Another partner switch can become the primary forwarder for the multicast traffic of another multicast group and provide load sharing of multicast traffic between partner switches. Furthermore, because the partner switches have the multicast traffic and state readily available, in the event of a switch or link failure to the primary forwarder, another partner switch can readily become the primary forwarder.

1 - 24 . (canceled) 
     
     
         25 . A switch, comprising:
 a local interface participating in a logical link, wherein the logical link comprises a plurality of physical links coupled to the switch and a second switch;   a multicast group management apparatus configured to determine that the switch is not a primary forwarder for a multicast group associated with the logical link; and   a forwarding apparatus configured to preclude the local interface from forwarding packets belonging to the multicast group via the logical link.   
     
     
         26 . The switch of  claim 25 , wherein the multicast group management apparatus is further configured to construct a control message for the second switch, wherein the notification message comprises a join request received via the local interface for the multicast group. 
     
     
         27 . New) The switch of  claim 25 , further comprising a packet processor configured to extract from a control message a join request for the multicast group, wherein the control message is received via an inter-switch port coupled to the second switch. 
     
     
         28 . The switch of  claim 27 , wherein the multicast group management apparatus is further configured to construct a second join request for the multicast group based on the extracted join request. 
     
     
         29 . The switch of  claim 25 , wherein the switch is a primary forwarder for a second multicast group. 
     
     
         30 . The switch of  claim 25 , wherein the a multicast group management apparatus is further configured to determine whether the switch is the primary forwarder based on a hash value calculated using an identifier of the multicast group. 
     
     
         31 . The switch of  claim 25 , wherein the switch and the second switch are members of a network of interconnected switches; and
 wherein the switch and the second switch are associated with an identifier identifying the network.   
     
     
         32 . A switch, comprising:
 a local interface participating in a logical link, wherein the logical link comprises a plurality of physical links coupled to the switch and a second switch;   a failure detection apparatus configured to detect a failure associated with a physical link in the plurality of physical links;   a multicast group management apparatus configured to, in response to detecting the failure, configure the switch as a primary forwarder for a multicast group associated with the logical link; and   a forwarding apparatus configured to identify the local interface as an egress interface for a packet belonging to the multicast group.   
     
     
         33 . The switch of  claim 32 , wherein multicast group management apparatus is further configured to, in response to detecting a recovery from the failure, configure the switch as a backup forwarder for the multicast group; and
 wherein the forwarding apparatus is further configured to preclude the local interface from forwarding packets belonging to the multicast group.   
     
     
         34 . The switch of  claim 32 , wherein multicast group management apparatus is further configured to, prior to configuring the switch as the primary forwarder, calculate a hash value using an identifier of the multicast group to determine whether the switch in a primary backup for the multicast group. 
     
     
         35 . A method, comprising:
 operating a local interface of a switch to participate in a logical link, wherein the logical link comprises a plurality of physical links coupled to the switch and a second switch;   determining that the switch is not a primary forwarder for a multicast group associated with the logical link; and   precluding the local interface from forwarding packets belonging to the multicast group via the logical link.   
     
     
         36 . The method of  claim 35 , further comprising constructing a control message for the second switch, wherein the notification message comprises a join request received via the local interface for the multicast group. 
     
     
         37 . The method of  claim 35 , further comprising extracting from a control message a join request for the multicast group, wherein the control message is received via an inter-switch port coupled to the second switch. 
     
     
         38 . The method of  claim 37 , further comprising constructing a second join request for the multicast group based on the extracted join request. 
     
     
         39 . The method of  claim 35 , wherein the switch is a primary forwarder for a second multicast group. 
     
     
         40 . The method of  claim 35 , further comprising determining whether the switch is the primary forwarder based on a hash value calculated using an identifier of the multicast group. 
     
     
         41 . The method of  claim 35 , wherein the switch and the second switch are members of a network of interconnected switches; and
 wherein the switch and the second switch are associated with an identifier identifying the network.   
     
     
         42 . A method, comprising:
 operating a local interface of a switch to participate in a logical link, wherein the logical link comprises a plurality of physical links coupled to the switch and a second switch;   detecting a failure associated with a physical link in the plurality of physical links;   in response to detecting the failure, configuring the switch as a primary forwarder for a multicast group associated with the logical link; and   identifying the local interface as an egress interface for a packet belonging to the multicast group.   
     
     
         43 . The method of  claim 42 , in response to detecting a recovery from the failure, further comprising:
 configuring the switch as a backup forwarder for the multicast group; and   precluding the local interface from forwarding packets belonging to the multicast group.   
     
     
         44 . The method of  claim 42 , further comprising, prior to configuring the switch as the primary forwarder, calculating a hash value using an identifier of the multicast group to determine whether the switch in a primary backup for the multicast group. 
     
     
         45 . A switch means, comprising:
 a local interface means for participating in a logical link, wherein the logical link comprises a plurality of physical links coupled to the switch means and a second switch means;   a multicast group management means for determining that the switch is not a primary forwarder for a multicast group associated with the logical link; and   a forwarding means for precluding the local interface from forwarding packets belonging to the multicast group via the logical link.   
     
     
         46 . A switch means, comprising:
 a local interface means for participating in a logical link, wherein the logical link comprises a plurality of physical links coupled to the switch means and a second switch means;   a failure detection means for detecting a failure associated with a physical link in the plurality of physical links;   a multicast group management means for, in response to detecting the failure, configuring the switch means as a primary forwarder for a multicast group associated with the logical link; and   a forwarding means for identifying the local interface as an egress interface for a packet belonging to the multicast group.