Brocade Multi-Service IronWare Multicast Configuration Guide (Supporting R05.6.00) - Manual (Page 103)

Multi-Service IronWare Multicast Configuration Guide 91
53-1003032-02
DVMRP overview
1
NOTE
MSDP and Anycast RP do not interoperate. If transitioning from MSDP to Anycast RP or vice versa,
all RPs in the network must be configured for the same method of RP peering; either Anycast RP or
MSDP.
DVMRP overview
The Brocade device provides multicast routing with the Distance Vector Multicast Routing Protocol
(DVMRP) routing protocol. DVMRP uses IGMP to manage the IP multicast groups.
DVMRP is a broadcast and pruning multicast protocol that delivers IP multicast datagrams to its
intended receivers. The receiver registers the interested groups using IGMP. DVMRP builds a
multicast delivery tree with the sender forming the root. Initially, multicast datagrams are delivered
to all nodes on the tree. Those leaves that do not have any group members send prune messages
to the upstream router, noting the absence of a group. The upstream router maintains a prune
state for this group for the given sender. A prune state is aged out after a given configurable
interval, allowing multicasts to resume.
DVMRP employs reverse path forwarding and pruning to keep source specific multicast delivery
trees with the minimum number of branches required to reach all group members. DVMRP builds a
multicast tree for each source and destination host group.
Initiating DVMRP multicasts on a network
Once DVMRP is enabled on each router, a network user can begin a video conference multicast
from the server on R1. Multicast Delivery Trees are initially formed by source-originated multicast
packets that are propagated to downstream interfaces as seen in
Figure 13 . When a multicast
packet is received on a DVMRP-capable router interface, the interface checks its DVMRP routing
table to determine whether the interface that received the message provides the shortest path
back to the source. If the interface does provide the shortest path, the interface forwards the
multicast packet to adjacent peer DVMRP routers, except for the router interface that originated the
packet. Otherwise, the interface discards the multicast packet and sends a prune message back
upstream. This process is known as reverse path forwarding.
TABLE 24 Display of show ip pim-anycast-rp
This field... Displays...
Number of Anycast RP: The Number of Anycast RP specifies the number of Anycast RP sets in
the multicast domain.
Anycast RP: The Anycast RP address specifies a shared RP address used among
multiple PIM routers.
ACL ID: The ACL ID specifies the ACL ID assigned.
ACL Name The ACL Name specifies the name of the Anycast RP set.
ACL Filter The ACL Filter specifies the ACL filter state SET or UNSET.
Peer List The Peer List specifies host addresses that are permitted in the Anycast
RP set.