Cisco Systems 78-11741-02 Wireless Office Headset User Manual


 
Configuring IP Multicast Routing
Load Splitting IP Multicast Traffic Across Equal-Cost Paths Configuration Task List
IPC-441
Cisco IOS IP Configuration Guide
Stub IP multicast routing allows stub sites to be configured quickly and easily for basic multicast
connectivity, without the flooding of multicast packets and subsequent group pruning that occurs in
dense mode, and without excessive administrative burden at the central site.
Before configuring stub IP multicast routing, you must have IP multicast routing configured on both the
stub router and the central router. You must also have PIM dense mode configured on both the incoming
and outgoing interfaces of the stub router.
Two steps are required to enable stub IP multicast routing. One task is performed on the stub router, and
the other is performed on a central router one hop away from the stub router. By definition, a stub region
is marked by a leaf router. That is, the stub router (leaf router) is the last stop before any hosts receiving
multicast packets or the first stop for anyone sending multicast packets.
The first step is to configure the stub router to forward all IGMP host reports and leave messages
received on the interface to an IP address. The reports are re-sent out the next hop interface toward the
IP address, with the source address of that interface. This action enables a sort of “dense mode” join
message, allowing stub sites not participating in PIM to indicate membership in multicast groups.
To configure the stub router to forward IGMP host reports and leave messages, use the following
command in interface configuration mode. Specify the IP address of an interface on the central router.
When the central router receives IGMP host report and leave messages, it appropriately adds or removes
the interface from its outgoing list for that group.
The second step is to configure an access list on the central router to filter all PIM control messages from
the stub router. Thus, the central router does not by default add the stub router to its outgoing interface
list for any multicast groups. This task has the side benefit of preventing a misconfigured PIM neighbor
from participating in PIM.
To filter PIM control messages, use the following command in interface configuration mode:
For an example of stub IP multicast routing, see the section “Stub IP Multicast Example” later in this
chapter.
Load Splitting IP Multicast Traffic Across Equal-Cost Paths
Configuration Task List
To configure load splitting of IP multicast traffic across equal-cost paths, perform the optional tasks
described in either of the following sections:
Enabling Native Load Splitting (Optional)
Enabling Load Splitting Across Tunnels (Optional)
Command Purpose
Router(config-if)# ip igmp helper-address
ip-address
On the stub router, forwards all IGMP host reports and leave
messages to the specified IP address on a central router.
Command Purpose
Router(config-if)# ip pim neighbor-filter
access-list
On the central router, filters all PIM control messages based on
the specified access list.