Brocade Communications Systems IPMC5000PEF Passive Multicast Route Insertion, Configuring Pmri

Passive Multicast Route Insertion

•If more than one router has the same DR priority on a subnet (as in the case of default DR priority on all), the router with the numerically highest IP address on that subnet will get elected as the DR.

•The DR priority information is used in the DR election only if all the PIM routers connected to the subnet support the DR priority option. If there is at least one PIM router on the subnet that does not support this option, then the DR election falls back to the backwards compatibility mode in which the router with the numerically highest IP address on the subnet is declared the DR regardless of the DR priority values.

Passive Multicast Route Insertion

To prevent unwanted multicast traffic from being sent to the CPU, IPv6 PIM routing and Passive Multicast Route Insertion (PMRI) can be used together to ensure that multicast streams are only forwarded out ports with interested receivers and unwanted traffic is dropped in hardware on Layer 3 routers.

PMRI enables a Layer 3 switch running IPv6 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 router (transit network).

When a multicast stream has no output interfaces, the Layer 3 switch can drop packets in hardware if the multicast traffic meets the following conditions in IPv6 PIM-SM.

•The route has no OIF.

•The directly connected source passes source RPF check and completes data registration with the RP, or the non-directly connected source passes source RPF check.

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.

Configuring PMRI

PMRI is enabled by default. To disable PMRI, enter the following commands.

device(config)# ipv6 router pim device(config-ipv6-pim-router)# hardware-drop-disable

To disable PMRI for a specified VRF, enter the commands as shown in the following example.

device(config)# ipv6 router pim vrf blue device(config-ipv6-pim-router-vrf-blue)# hardware-drop-disable

Syntax: [no] hardware-drop-disable

Displaying hardware-drop

Use the show ipv6 pim sparse command to display if the hardware-drop feature has been enabled or disabled.

Brocade# show ipv6 pim sparse
Global PIM Sparse Mode Settings			Current Count	:	7
Maximum Mcache	:	4096
Hello interval	:	30	Neighbor timeout	:	105

FastIron Ethernet Switch IP Multicast Configuration Guide	175
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