Cisco ASR 9000 Series Software Manual page 47

Implementing Layer-3 Multicast Routing on Cisco IOS XR Software
override the inheritance mechanism, you can enter interface configuration submode and explicitly enter a
different command parameter.
For example, in the following configuration you could quickly specify (under router PIM configuration mode)
that all existing and new PIM interfaces on your router will use the hello interval parameter of 420 seconds.
However, Packet-over-SONET/SDH (POS) interface 0/1/0/1 overrides the global interface configuration and
uses the hello interval time of 210 seconds.
RP/0/RSP0/CPU0:router(config)#
RP/0/RSP0/CPU0:router(config-pim-default-ipv4)#
RP/0/RSP0/CPU0:router(config-pim-default-ipv4)#
RP/0/RSP0/CPU0:router(config-pim-ipv4-if)#
The following is a listing of commands (specified under the appropriate router submode) that use the inheritance
mechanism:
router pim
dr-priority
hello-interval
join-prune-interval
multicast-routing
version
query-interval
query-max-response-time
explicit-tracking
router mld
interface all disable
version
query-interval
query-max-response-time
explicit-tracking
router msdp
connect-source
sa-filter
filter-sa-request list
remote-as
ttl-threshold
Understanding Interface Configuration Inheritance Disablement
As stated elsewhere, Cisco IOS XR Software allows you to configure multiple interfaces by applying
configurations within a multicast routing submode that can be inherited by all interfaces.
To override the inheritance feature on specific interfaces or on all interfaces, you can enter the address-family
IPv4 or IPv6 submode of multicast routing configuration mode, and enter the interface-inheritance disable
command together with the interface type interface-path-id or interface all command. This causes PIM or
IGMP protocols to disallow multicast routing and to allow only multicast forwarding on those interfaces
specified. However, routing can still be explicitly enabled on specified individual interfaces.
The following configuration disables multicast routing interface inheritance under PIM and IGMP generally,
although forwarding enablement continues. The example shows interface enablement under IGMP of
GigabitEthernet 0/6/0/3:
RP/0/RSP0/CPU0:router#
RP/0/RSP0/CPU0:router(config-mcast-default-ipv4)#
RP/0/RSP0/CPU0:router(config-mcast-default-ipv4)#
router pim
multicast-routing address-family ipv4
Cisco ASR 9000 Series Aggregation Services Router Multicast Configuration Guide, Release 5.1.x
Understanding Interface Configuration Inheritance Disablement
hello-interval 420
interface pos 0/1/0/1
hello-interval 210
interface all enable
interface-inheritance disable
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