Group-to-RP Mapping Algorithm PIM Working Group Bharat Joshi Infosys Technologies Ltd. draft-joshi-pim-group-rp-mapping-00.txt

Need for a standard algorithm No existing RFC/Draft defines a complete algorithm. A standard algorithm is useful in interoperability. A standard algorithm can be used to predict the RP for a given Group while running outside a router. This can be used for diagnosing PIM protocol states.

Existing Algorithm PIM-SM has defined an algorithm which does not: –Consider the origin of a Group-to-RP mapping and therefore treat all of them equally. –Provide the flexibility that a specific statically created Group-to-RP mapping can override any dynamically learned mappings. –Provide the flexibility to give higher priority to a specific PIM mode. PIM-STD-MIB has defined an algorithm that: –Is not deterministic as it uses implementation-specific values. –Can not be referenced by an implementation.

Proposed Algorithm Select those Group-to-RP mappings that contains the Group address being looked up. Select those mappings that are learned using 'static' configuration and are configured with 'override-dynamic' flag. Perform longest prefix match. Select mappings based on PIM Mode. PIM-BIDIR is preferred to PIM-SM. Select mappings based on origin of Group-to-RP mapping. Preference is 'bsr', 'auto-rp', 'embedded', 'static' and 'other'. Perform the Hash function. If there are still multiple mappings available, select the one that has higher IP address for RP address.

Next Step Review in WG mailing list. Working group item?