Brocade MLX Series and Brocade NetIron XMR Diagnostic Guide ...

Multicast DiagnosticsChapter8This chapter provides diagnostic information about IP multicast environments on Brocade NetIronXMR series and Brocade MLX series routers.IP multicastingMulticast protocols allow a group or channel to be accessed over different networks by multiplestations (clients) for the receipt and transmission of multicast data.Brocade devices support two multicast routing protocols—Distance Vector Multicast RoutingProtocol (DVMRP) and Protocol-Independent Multicast (PIM) protocol along with the Internet GroupManagement Protocol (IGMP).PIM and DVMRP are broadcast and pruning multicast protocols that deliver IP multicast datagrams.DVMRP and PIM build a different multicast tree for each source and destination host group.DVMRPBrocade devices provide multicast routing with the Distance Vector Multicast Routing Protocol(DVMRP). DVMRP uses IGMP to manage the IP multicast groups.DVMRP is a broadcast and pruning multicast protocol that delivers IP multicast datagrams tointended receivers. The receiver registers the interested groups using IGMP. DVMRP builds amulticast delivery tree with the sender forming the root. Initially, multicast datagrams are deliveredto all nodes on the tree. Those leaves that do not have any group members send prune messagesto the upstream router, noting the absence of a group. The upstream router maintains a prunestate for this group for the given sender. A prune state is aged out after a given configurableinterval, allowing multicasts to resume.DVMRP show commandsYou can use show commands to display the following DVMRP information:• DVMRP group information• DVMRP interface information• DVMRP multicast cache information• DVMRP neighbor information• DVMRP active prune information• Available multicast resources• IP multicast route information• Active multicast traffic informationBrocade MLX Series and Brocade NetIron XMR Diagnostic Guide 26953-1002426-02