494 CHAPTER 48: MSDP CONFIGURATIONTracing the transmission path of an SA message over the networkYou can use the msdp-tracert command in any view to trace the path alongwhich the multicast data travels from the multicast source to the destinationreceiver over the network, so as to locate errors, if any.You can locate message loss and configuration errors by tracing the network pathof the specified (S, G, RP) entries. Once the transmission path of SA messages isdetermined, correct configuration can prevent the flooding of SA messages.MSDP ConfigurationExampleConfiguration Exampleof MSDP Based on BGPRoutesNetwork requirementsTwo ISPs maintains their ASs, AS 100 and AS 200 respectively. OSPF is runningwithin each AS, and BGP is running between the two ASs. PIM-SM1 belongs to AS100, while PIM-SM2 and PIM-SM3 belong to AS 200.Suppose each PIM-SM domain is a single-BSR-managed domain, having 0 or 1multicast source S and multiple receivers. OSPF runs within each domain toprovide unicast routes. An MSDP peering relationship is established between theRPs based on BGP routes within each PIM-SM network.Loopback 0 on Switch C, Switch D and Switch E functions as the C-BSR and C-RPof its own PIM-SM domain respectively. An MSDP peering relationship isestablished between Switch C and Switch F based on EBGP routes, and an MSDPpeering relationship is established between Switch F and Switch D based on IBGProutes.Display the (S, G) state learned from MSDP peers display msdp sa-cache [ group-address |[ source-address ] ][autonomous-system-number ]Display the number of sources and groups in theMSDP cachedisplay msdp sa-count[autonomous-system-number ]Reset the TCP connection with the specifiedMSDP peerreset msdp peer peer-addressClear the cached SA messages reset msdp sa-cache [ group-address ]Clear the statistics information of the specifiedMSDP peer without resetting the MSDP peerreset msdp statistics [ peer-address ]Table 394 Trace the transmission path of an SA message over the networkOperation CommandTrace the transmission path of an SA message overthe networkmsdp-tracert source-addressgroup-address rp-address [ max-hopsmax-hops ] [ next-hop-info | sa-info |peer-info ]* [ skip-hops skip-hops ]Table 393 Display and debug MSDP configurationOperation Command
