Brocade MLX Series and Brocade NetIron XMR Diagnostic Guide ...

8PIM DM and PIM SMclear ip msdp sa-cacheSyntax: clear ip msdp sa-cache This command clears all of the cache entries. Use the variable to clear only the entriesmatching either a source or a group.To clear MSDP statistics, enter the clear ip msdp statistics command at the Privileged EXEC level ofthe CLI.clear ip msdp statisticsSyntax: clear ip msdp statistics This command clears statistics for all the peers. To clear statistics for a specific peer, enter thepeer’s IP address using the variable.Configuration notes• MSDP depends on BGP and Multiprotocol BGP (MBGP) for inter-domain operations.• Routers that run MSDP usually also run BGP. The source address used by the MSDP router isnormally configured to be the same source address used by BGP.• For MSDP mesh groups, on each device that will be part of the mesh group, there must be amesh group definition for all the peers in the mesh group.• It is recommended that you use the connect-source loopback parameter when issuingthe msdp-peer command. If you do not use this parameter, the Brocade device uses theoutgoing interface’s IP address. You must also make sure the IP address of the connect-sourceloopback parameter is the source IP address used by the PIM-RP, and the BGP router.Common diagnostic scenarios• High CPU usage with MSDP traffic between two peers.This issue can be resolved by resetting both peers.• PIM SM Multicast packets are not being successfully transmitted.A device downstream has multicast passive and PIM snooping enabled. Once PIM snooping isdisabled on the downstream device, and added on MBGP links, the problem is resolved.• Unable to remove an MSDP peer.This issue is resolved by upgrading the software version to reflect the latest patches andversions.PIM DM and PIM SMProtocol-Independent Multicast (PIM) helps to simplify the complexity of the routing protocol. PIM issimilar to DVMRP in that PIM builds source-routed multicast delivery trees and employs reversepath check when forwarding multicast packets.There are two PIM modes: Dense and Sparse. The Dense Mode (DM) is suitable for denselypopulated multicast groups, primarily in the LAN environment. The Sparse Mode (SM) is suitable forsparsely populated multicast groups with the focus on WAN.288 Brocade MLX Series and Brocade NetIron XMR Diagnostic Guide53-1002426-02