KB.15.15

VLAN context commands for configuring PIM-SM

PIM-SM must be configured on at least one VLAN in the router before it can be configured as a

C-BSR or a C-RP.

Enabling or disabling IGMP in a VLAN

IGMP must be enabled in VLANs on edge routers where multicast receivers (end points) are

connected and will be requesting to join multicast groups.

Syntax:

[no] ip igmp

[no] vlan [vid] ip igmp

Enables or disables IGMP operation in the current VLAN. Configuring IGMP on the

router is required in VLANs supporting edge router operation. See Figure 7

(page 39).

Enabling or disabling PIM-SM per-VLAN

Syntax:

ip pim-sparse [ ip-addr [any | ip-addr] ]

vlan [vid] ip pim-sparse [ ip-addr [any | ip-addr] ]

no [vlan [vid]] ip pim-sparse

This command enables or disables PIM-SM in the designated VLAN interface and

sets the source (and designated router) IP address for PIM-SM packets sent from the

interface. Executing the command without specifying an IP address option causes

the router to default to the any option, below. (Default: PIM-SM disabled)

ip-addr any Enables the router to dynamically determine from the

VLAN's current IP configuration the source IP address

to use for PIM-SM packets sent from the VLAN interface.

NOTE: Using this command after a source IP address

has already been set does not change that setting.

ip-addr [ip-addr] Specifies one of the VLAN's currently existing IP

addresses for use as the source IP address for PIM-SM

packets sent from the VLAN interface.

Note that ip-addr must first be statically configured

on the VLAN.

NOTE: To change an existing source IP address

setting, you must use this command option.

Changing the interval for PIM-SM neighbor notification

Syntax:

ip pim-sparse hello-interval [5-300]

vlan vid ip pim-sparse hello-interval [5-300]

Changes the frequency at which the router transmits PIM hello messages on the

current VLAN. The router uses hello packets to inform neighbor routers of its

presence.

The router also uses this setting to compute the hello hold time, which is included

in hello packets sent to neighbor routers. hello hold time tells neighbor routers how

68 PIM-SM (Sparse Mode)