H3C S3600-28PSI System Description

Also see for S3600-28FEI: Datasheet Operation manual Operation manual

H3C S3600-28PSI System Description Manual pdf 66 page image

System DescriptionH3C S3600 Series Ethernet Switches Chapter 3 Software Features3-7hearing an IGMP Leave message, it removes the host from the multicast table. Bycontinuously listening to IGMP packets, the switch creates and maintains a L2 MACmulticast address table and based on which forwards the multicast packets sent fromthe upstream router.3.4.2 IGMPThe Internet group management protocol (IGMP) runs between hosts and multicastrouters for tracing and learning the membership of the hosts. A multicast router learnswhether there is a multicast member on a subnet connected to it by periodicallysending IGMP Host-Query messages. A host sends IGMP Report messages for joininga multicast group. The S3600 series support both IGMPv1 and IGMPv2.3.4.3 PIM-DMThe protocol-independent multicast (PIM) runs between multicast routers. Using PIM, amulticast router traces and learns which multicast packets are to be forwarded to otherrouters, and then transmits them to the LANs connected to the multicast routers.The protocol independent multicast-dense mode (PIM-DM) is applied to a multicastenvironment where multicast group members are dense. In PIM-DM, a router assumesthat all other routers agree to forward multicast packets for multicast groups. If therouter receives a multicast packet but has no directly connected multicast groupmember or PIM neighbor, it sends a Prune message back to the multicast source. Thesubsequent multicast packets are not to be transmitted to this router. By using thisflood-prune mechanism, IM-DM creates a multicast distribution tree with the multicastsource as the root.3.4.4 PIM-SMDifferent from PIM-DM, the protocol independent multicast-sparse mode (PIM-SM)applies to a multicast environment where multicast group members are sparse. InPIM-SM, a router assumes that none of other routers agree to forward multicastpackets for multicast groups, unless they declare so. If a host wants to join a multicastgroup, the multicast router that is directly connected to it sends a PIM Join message tothe rendezvous point (RP) where the host is registered. The RP then forwards the Joinmessage to the multicast source. In PIM-SM, the multicast packet is forwarded along ashared distribution tree.