Understanding Multicast Routing on a Chassis Cluster

Multicast routing support across nodes in a chassis cluster allows multicast protocols, such as Protocol Independent Multicast (PIM) versions 1 and 2, Internet Group Management Protocol (IGMP), Session Announcement Protocol (SAP), and Distance Vector Multicast Routing Protocol (DVMRP), to send traffic across interfaces in the cluster. Note, however, that the multicast protocols should not be enabled on the chassis management interface (fxp0) or on the fabric interfaces (fab0 and fab1). Multicast sessions will be synched across the cluster and will be maintained during redundant group failovers. During failover, as with other types of traffic, there might be some multicast packet loss.

Multicast data forwarding in a chassis cluster uses the incoming interface to determine whether or not the session remains active. Packets will be forwarded to the peer node if a leaf session’s outgoing interface is on the peer instead of on the incoming interface’s node. Multicast routing on a chassis cluster supports tunnels for both incoming and outgoing interfaces.

Multicast configuration on a chassis cluster is the same as multicast configuration on a standalone device (see the “Configuring a Multicast Network” chapter of the JUNOS Software Routing Protocols and Policies Configuration Guide for Security Devices).

Related Topics

• JUNOS Software Feature Support Reference for SRX Series and J Series Devices
• Chassis Cluster Overview
• Understanding Chassis Cluster Formation