KB.15.15

Additionally, the following commands may be required:

• To later add to or change multicast groups, or to delete multicast groups, use the command

rp-candidate group-prefix [group-addr | group-mask].

• To disable C-RP operation without removing the current CRP configuration, use the command

no rp-candidate.

• The no form of these commands:

Deletes the RP source IP VLAN configuration.◦

◦ Deletes the multicast group assignments configured on the router for this RP.

◦ Disables the router from being an RP candidate.

The <vid> command identifies the VLAN source of the IP address to advertise as the RP candidate

address for the router.

The command group-prefix [group-addr/mask] specifies the multicast group(s) to advertise

as supported by the RP candidate. Use this option when you want to enable the C-RP and

simultaneously configure it to support a subset of multicast addresses or ranges of addresses instead

of all possible multicast addresses.

A group prefix can specify all multicast groups (224.0.0.0 to 239.255.255.255), a range (subset)

of groups, or a single group. A given address is defined by its nonzero octets and mask. The mask

is applied from the high end (leftmost) bits of the address and must extend to the last nonzero bit

in the lowest-order, nonzero octet. Any intervening zero or nonzero octet requires eight mask bits.

Following are examples.

Example 33 228.0.0.64/26:

Defines a multicast address range of 228.0.0.64 through 228.0.0.127. (The last six bits of the

rightmost octet are wildcards.)

Example 34 228.0.0.64/30:

Defines a multicast address range of 228.0.0.64 through 228.0.0.67. (The last two bits of the

rightmost octet are wildcards.)

Example 35 228.0.0.64/32:

Defines a single multicast address of 228.0.0.64. (There are no wildcards in this group prefix.)

Example 36 228.0.0.64/25:

Creates an error condition caused by the mask failing to include the last (rightmost) nonzero bit

in the lowest-order, nonzero octet. (That is, this mask supports an address of 228.0.0.128, but

not 228.0.0.64.)

NOTE: The larger the mask, the smaller the range of multicast addresses supported. A mask of

32 bits always specifies a single multicast address. For example 230.0.15.240/32 defines a

single multicast address of 230.0.15.240.

Enabling or disabling C-RP operation

Use this command when the router is already configured with a source IP VLAN ID and you want

to enable or disable C-RP operation on the router.

74 PIM-SM (Sparse Mode)