10G Core Routing Switch User Manual
陈泽科技有限公司
- - 73 - -
www.stephen-tele.com
member of a group (and enable fast switching). This procedure is optional.
Command
Purpose
Step 1
config terminal
Enter global configuration mode.
Step 2
ip igmp interface
interface-id
static-group add
group-address
Configure the switch as a statically connected
member of a group.
By default, this feature is disabled.
Step 3
exit
Return to privileged EXEC mode.
Step 4
write
(Optional) Save your entries in the configuration file.
To remove the switch as a member of the group, use
ip igmp interface
interface-id
static-group delete
group-address
globle configuration command.
PIM-SM Configuration
PIM-SM Overview
Introduction to PIM-SM
PIM-SM (Protocol Independent Multicast, Sparse Mode) belongs to sparse mode multicast routing protocols. PIM-SM
is mainly applicable to large-scale networks with broad scope in which group members are relatively sparse.
Different from the flood & prune principle of the dense mode, PIM-SM assumes that all hosts do not need to receive
multicast packets, unless there is an explicit request for the packets.
PIM-SM uses the RP (Rendezvous Point) and the BSR (Bootstrap Router) to advertise multicast information to all
PIM-SM routers and uses the join/prune information of the router to build the RP-rooted shared tree (RPT), thereby
reducing the bandwidth occupied by data packets and control packets and reducing the process overhead of the router.
Multicast data flows along the shared tree to the network segments the multicast group members are on. When the
data traffic is sufficient, the multicast data flow can switch over to the SPT (Shortest Path Tree) rooted on the source to
reduce network delay. PIM-SM does not depend on the specified unicast routing protocol but uses the present unicast
routing table to perform the RPF check.
Running PIM-SM needs to configure candidate RPs and BSRs. The BSR is responsible for collecting the information from
the candidate RP and advertising the information.
PIM-SM Working Principle
The PIM-SM working process is as follows: neighbor discovery, building the RP-rooted shared tree (RPT), multicast
source registration and SPT switchover etc. The neighbor discovery mechanism is the same as that of PIM-DM, which
will not be described any more.
I. Build the RP shared tree (RPT)
When hosts join a multicast group G, the leaf routers that directly connect with the hosts send IGMP messages to learn
the receivers of multicast group G. In this way, the leaf routers calculate the corresponding rendezvous point (RP) for
multicast group G and then send join messages to the node of a higher level toward the rendezvous point (RP). Each
router along the path between the leaf routers and the RP will generate (*, G) entries in the forwarding table,
indicating that all packets sent to multicast group G are applicable to the entries no matter from which source they are
