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Protocol Independent Multicast (PIM)

PIM was designed to take advantage of two existing multicast routing protocols, DVMRP and CBT. It exhibits the behavior of a protocol in a region of dense group membership flooding multicast packets using Reverse Path Multicasting, while also taking advantage of the work done for sparse group membership in Core Based Trees. Hence, the protocol has two modes, dense and sparse. Currently, only dense mode is implemented in Gated. An overview of PIM can be found in [PIM Arch]. The detailed protocol specification is also available as [PIM Spec]. Both of these documents are considered Work in Progress.

The PIM Statement

pim yes | no | on | off [ { queryinterval sec ; routertimeout sec ; prunetimeout sec ; inactivitytimeout sec ; graftacktimeout sec ; preference { direct preference ; kernel preference ; ospf preference ; ospfase preference ; rip preference ; hello preference ; static preference ; bgp preference ; egp preference ; idrp preference ; isis preference ; slsp preference ; } ; interface interface_list [[ enable] | [ disable]] [ mode [ dense | sparse]] ; traceoptions trace_options ; } ] ;

The pim statement enables or disables the PIM protocol. If the pim statement is not specified the default is pim off; If enabled, PIM will default to enabling all interfaces that are multicast capable. These interfaces are identified by the IFF_MULTICAST interface flag.

The options are as follows:

Tracing options

Packet tracing options (which may be modified with detail, send or recv):

All PIM packets.

PIM Router Query packets

PIM Register, Register Stop, and RP packets

PIM Join/Prune packets

PIM Assert packets

PIM Graft and Graft Ack packets

next up previous contents index
Next: EGP Up: Configuration Guide Previous: DVMRP

Laurent Joncheray
Wed Jun 12 15:35:22 EDT 1996