Brocade Communications Systems IPMC5000PEF manual Passive multicast route insertion

Passive multicast route insertion

The vrf parameter allows you to display IP PIM counters for the VRF instance specified by the vrf- name variable.

The following table displays the output from the show ip pim counter nsr command.

This field...	Displays...
Mcache sync	The mcache NSR sync queue that carries the NSR sync message for mcache updates.
pack	The number of NSR sync messages that are packed from the active module to the standby
	module.
unpack	The number of NSR sync messages that are received and unpacked by the standby module.
ack	The number of NSR sync acknowledgements received by the active module.
RPset sync	The RPset sync queue that carries the NSR sync message for RPset update.
BSR status	The BSR status sync queue that carries the NSR sync message for BSR information update.

Passive multicast route insertion

To prevent unwanted multicast traffic from being sent to the CPU, PIM routing and passive multicast route insertion (PMRI) can be used together to ensure that multicast streams are forwarded out only ports with interested receivers and unwanted traffic is dropped in hardware on Layer 3 switches.

PMRI enables a Layer 3 switch running PIM Sparse to create an entry for a multicast route (for example, (S,G)), with no directly attached clients or when connected to another PIM device (transit network).

When a multicast stream has no output interfaces (OIF), the Layer 3 switch can drop packets in hardware if the multicast traffic meets either of the following conditions:

In PIM-SM:

•‐ The route has no OIF and

‐If directly connected source passed source reverse-path forwarding (RPF) check and completed data registration with reverse path (RP) or

‐If non directly connected source passed source RPF check.

In PIM-DM:

•‐ The route has no OIF and

‐passed source RPF check and

‐Device has no downstream PIM neighbor.

If the OIF is inserted after the hardware-drop entries are installed, the hardware entries will be updated to include the OIFs.

NOTE

Disabling hardware-drop does not immediately take away existing hardware-drop entries, they will go through the normal route aging processing when the traffic stops.

78	FastIron Ethernet Switch IP Multicast Configuration Guide
	53-1003085-02