Implementing Layer-3 Multicast Routing
Multicast routing allows a host to send packets to a subset of all hosts as a group transmission rather than to a single host, as in unicast transmission, or to all hosts, as in broadcast transmission. The subset of hosts is known as group members and are identified by a single multicast group address that falls under the IP Class D address range from 188.8.131.52 through 184.108.40.206.
The multicast environment consists of senders and receivers. Any host, regardless of whether it is a member of a group, can send to a group. However, only the members of a group receive the message.
The following protocols are supported to implement multicast routing:
IGMP—IGMP is used between hosts on a network (for example, LAN) and the routers on that network to track the multicast groups of which hosts are members.
PIM SSM— Protocol Independent Multicast in Source-Specific Multicast (PIM-SSM) has the ability to report interest in receiving packets from specific source addresses (or from all but the specific source addresses), to an IP multicast address.
MLD Snooping is not supported until Cisco IOS XR Release 6.5.3. The support will be available in future releases.
Prerequisites for Implementing Multicast Routing
You must install and activate the multicast RPM package.
You must be familiar with IPv4 multicast routing configuration tasks and concepts.
Unicast routing must be operational.
Enables multicast routing and forwarding on all new and existing interfaces.
Router#config Router(config)#multicast-routing Router(config-mcast)#address-family ipv4 Router(config-mcast-default-ipv4)#interface all enable */In the above command, you can also indicate a specific interface (For example, interface TenGigE0/0/0/3) for enabling multicast only on that interface/* Router(config-mcast-default-ipv4)#commit
Router#show running multicast routing multicast-routing address-family ipv4 interface all enable !
Verify that the Interfaces are enabled for multicast.
Router#show mfib interface location 0/3/CPU0 Interface : FINT0/3/CPU0 (Enabled) SW Mcast pkts in : 0, SW Mcast pkts out : 0 TTL Threshold : 0 Ref Count : 2 Interface : TenGigE0/3/0/0/0 (Enabled) SW Mcast pkts in : 0, SW Mcast pkts out : 0 TTL Threshold : 0 Ref Count : 3 Interface : TenGigE0/3/0/9/0 (Enabled) SW Mcast pkts in : 0, SW Mcast pkts out : 0 TTL Threshold : 0 Ref Count : 13 Interface : Bundle-Ether1 (Enabled) SW Mcast pkts in : 0, SW Mcast pkts out : 0 TTL Threshold : 0 Ref Count : 4 Interface : Bundle-Ether1.1 (Enabled) SW Mcast pkts in : 0, SW Mcast pkts out : 0 TTL Threshold : 0