UMN:CLI User ManualV5812G3829.3.3.5 Cisco’s Router InteroperabilityRegister Message ChecksumWhen a multicast source registers with the RP, the DR encapsulates the multicast trafficfrom the source in the PIM register message, and unicasts it to the RP. The standard PIMprotocol specifies that the checksum field in the register message contains the checksumfor the entire register message excluding the data portion, the encapsulated multicasttraffic.The Cisco‘s routers, however, validate the checksum for the whole register messageincluding the data portion, resulting in incompatibility with the standard-based routers. Toguarantee compatibility with the Cisco‘s routers, the V5812G provides the checksumoption, which expands the range of the checksum calculation.To enable the Cisco checksum option, use the following command.Command Mode Descriptionip pim cisco-register-checksumGlobalEnables the Cisco checksum option.ip pim cisco-register-checksumgroup-list {<1-99> | <1300-1999>| WORD}Enables the Cisco checksum option for specifiedmulticast groups.1-99: IP standard access list1300-1999: IP standard access list (extended range)WORD: access list nameTo disable the Cisco checksum option, use the following command.Command Mode Descriptionno ip pim cisco-register-check-sum Global Disables the Cisco checksum option.Candidate RP MessageSome Cisco‘s BSRs do not comply with the BSR standards; they do not accept candidateRPs with a group prefix number of zero. You can configure the router to send candidateRP messages with the option for the compatibility with the Cisco‘s BSR.To enable the candidate RP message option for the Cisco compatibility, use the followingcommand.Command Mode Descriptionip pim crp-cisco-prefixGlobalEnables the candidate RP message option for theCisco compatibility.no ip pim crp-cisco-prefix Disables the candidate RP message option for theCisco compatibility.Excluding GenID OptionPIM hello messages may contain the generation ID (GenID) in the option fields, which isa random value for the interface on which the hello message is sent. The GenID isregenerated whenever PIM forwarding is started or restarted on the interface. It enables
