User's Manual

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48.4.8 MSDP Troubleshooting
When MSDP is being configured, it may not function because of the physical link not working or configuration
mistakes. Attention should be paid to the following items in order to make MSDP work:
 Make sure the physical link works well
 Make sure inner-domain and inter-domain routing works
 Make sure PIM-SM is applied in every domain as the inner-domain routing protocol, and configuration
for PIM-SM works well
 Make sure MSDP is enabled, and the link status of the MSDP enabled Peer is UP
 Use the command show msdp global to check whether the MSDP configuration is correct
If the MSDP problems cannot be solved through all the methods provided above, please issue the
command debug msdp to get the debugging messages within three minutes, and send them to the technical
service center of our company.
48.5 ANYCAST RP Configuration
48.5.1 Introduction to ANYCAST RP
Anycast RP is a technology based on PIM protocol, which provides redundancy in order to recover as soon as
possible once an RP becomes unusable.
The kernel concept of Anycast RP is that the RP addresses configured all over the whole network exist on
multiple multicast servers (the most common situation is that every device providing ANYCAST RP uses
LOOPBACK interface, and using the longest mask to configures RP addresses on this interface), while the
unicast routing algorithm will make sure that PIM routers can always find the nearest RP, thus , providing a
shorter and faster way to find RP in a larger network., Once an RP being used becomes unusable, the unicast
routing algorithm will ensure that the PIM router can find a new RP path fast enough to recover the multicast
server in time. Multiple RP will cause a new problem that is if the multicast source and the receivers are
registered to different RP, some receivers will not be able to receive data of multicast source (obviously, the
register messages only prefer the nearest RP). So, in order to keep the communication between all RP,
Anycast RP defines that the nearest RP to the multicast source should forward the source register messages
to all the other RP to guarantee that all joiners of the RP can find the multicast source.
The method to realize the PIM-protocol-based Anycast RP is that: maintaining an ANYCAST RP list on every
switch configured with Anycast RP and using another address as the label to identify each other. When one
Anycast RP device receives a register message, it will send the register message to other Anycast RP
devices while using its own address as the source address, to notify all the other devices of the original
destination.