Internet Group Management Protocol And Multicast Listener Discovery - Cisco CRS Series Configuration Manual

Implementing Multicast Routing on Cisco IOS XR Software
• Anycast RP is not supported for BIDIR in the MVRF and in native.
• Data MDT is not supported for BIDIR in the MVRF.
• Extranet is not supported for BIDIR traffic.
• MVPN BIDIR in the core is not supported.
• The SM scale is about 350 VRFs per system and the maximum BIDIR scale is expected to be around
E3 Linecard Limitations
• Only 1k BIDIR routes (without qos) are supported on E3.
• If multicast QoS is applied, then we recommend having only <= 1k routes.
• Only 10 egress interfaces are supported.
• If Multicast QoS is enabled on E3, then policy can have a maximum of 5 queuing classes, (including
It is recommended to have less BIDIR scale on E3 Linecard, as it requires lot of resources to support
Note
BIDIR support such as MGID usage, TLU memory, and CPU utilization.

Internet Group Management Protocol and Multicast Listener Discovery

Cisco IOS XR Software provides support for Internet Group Management Protocol (IGMP) over IPv4 and
Multicast Listener Discovery (MLD) over IPv6.
IGMP (and MLD) provide a means for hosts to indicate which multicast traffic they are interested in and for
routers to control and limit the flow of multicast traffic throughout the network. Routers build state by means
of IGMP and MLD messages; that is, router queries and host reports.
A set of queries and hosts that receive multicast data streams from the same source is called a multicast group.
Hosts use IGMP and MLD messages to join and leave multicast groups.
IGMP messages use group addresses, which are Class D IP addresses. The high-order four bits of a Class D
Note
address are 1110. Host group addresses can be in the range 224.0.0.0 to 239.255.255.255. The address
224.0.0.0 is guaranteed not to be assigned to any group. The address 224.0.0.1 is assigned to all systems
on a subnet. The address 224.0.0.2 is assigned to all routers on a subnet.
IGMP and MLD Versions
The following points describe IGMP versions 1, 2, and 3:
• IGMP Version 1 provides for the basic query-response mechanism that allows the multicast router to
10% of SM scale. Thus, the BIDIR scale is about 35 VRFs.
class default), assuming 1k scale.
determine which multicast groups are active and for other processes that enable hosts to join and leave
a multicast group.
Cisco IOS XR Multicast Configuration Guide for the Cisco CRS Router, Release 5.2.x
Internet Group Management Protocol and Multicast Listener Discovery
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