Reference Guide

PIM Sparse-Mode | 763
Configure a Designated Router
Multiple PIM-SM routers might be connected to a single LAN segment. One of these routers is elected to
act on behalf of directly connected hosts. This router is the Designated Router (DR).
The DR is elected using hello messages. Each PIM router learns about its neighbors by periodically
sending a hello message out of each PIM-enabled interface. Hello messages contain the IP address of the
interface out of which it is sent and a DR priority value. The router with the greatest priority value is the
DR. If the priority value is the same for two routers, then the router with the greatest IP address is the DR.
By default the DR priority value is 192, so the IP address determines the DR.
Create Multicast Boundaries and Domains
A PIM domain is a contiguous set of routers that all implement PIM and are configured to operate within a
common boundary defined by PIM Multicast Border Routers (PMBRs). PMBRs connect each PIM
domain to the rest of the internet.
Create multicast boundaries and domains by filtering inbound and outbound Bootstrap Router (BSR)
messages per interface, using the [
ip | ipv6] pim bsr-border command. This command is applied to the
subsequent inbound and outbound updates. Already existing BSR advertisements are removed by timeout.
Remove candidate RP advertisements using the
clear [ip | ipv6] pim rp-mapping command.
IP Version Task Command Syntax Command Mode
IPv4 Assign a DR priority value.
ip pim dr-priority value
INTERFACE
IPv4 Change the interval at which a router sends
hello messages.
ip pim query-interval seconds INTERFACE
IPv4 Display the current value of DR parameters.
show ip pim interface
EXEC Privilege
IPv6 Assign a DR priority value.
ipv6 pim dr-priority value
INTERFACE
IPv6 Change the interval at which a router sends
hello messages.
ipv6 pim query-interval seconds INTERFACE
IPv6 Display the current value of DR parameters.
show ipv6 pim interface
EXEC Privilege
IP Version Task Command Syntax Command Mode
IPv4 Filter inbound and outbound Bootstrap Router
messages per interface.
ip pim bsr-border
INTERFACE
Remove candidate RP advertisements.
clear ip pim rp-mapping
EXEC PRIVILEGE