GateD Configuration Guide - DVMRP Configuration

# 6.3.2 Intra-Domain Routing Protocols

## 1. Distance Vector Multicast Routing Protocol (DVMRP)

DVMRP is the original IP Multicast routing protocol. It was designed to run over both multicast capable lans (like Ethernet) as well as through non-multicast capable routers. In this case, the IP Multicast packets are "tunneled" through the routers as unicast packets. This replicates the packets and has an effect on performance, but has provided an intermediate solution for IP Multicast routing on the Internet while router vendors decide to support native IP Multicast routing.

An earlier version of DVMRP was documented as RFC 1075 but it is not representative of the protocol in use today. The GATED version of DVMRP is compatible with the XEROX PARC releases 2.x and 3.x. It will perform pruning and grafting if the upstream neighbor supports it. It understands the capability flags introduced in XEROX PARC Release 3.5.

This is a preliminary release of DVMRP.

## The DVMRP Statement

    dvmrp yes | no | on | off [ {
        interface interface_list dvrmp_parameters
    	[enable | disable]
    	[metric metric]
    	[threshold threshold]
    	[ratelimit rate]
    	[advertise network [(mask mask) | (masklen number)]
    		[metric metric]] ;
        tunnel host lcladdr local_address
    	[enable | disable]
    	[metric metric]
    	[threshold threshold]
    	[ratelimit rate] ;
        traceoptions trace_options ;
    } ] ;

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

Note: only one multicast routing protocol can be configured on a port at a time.

The options are as follows:

interface interface_list dvmrp_parameters
  Enables or disables DVMRP on this interface or list of interfaces.
  The possible dvmrp_parameters are:
  disable

  Specifies that DVMRP packets received via the specified interface will be ignored. The default is to listen to DVMRP on all multicast capable interfaces.

  enable

  This is the default. This argument may be necessary when `disable` is used on a wildcard interface descriptor.

  metric

  This command provides a way to configure the metric on a physical port or tunnel. This metric will be added to all routes that are learned via this interface.

  threshold

  This command provides a way to configure the threshold on a physical port or tunnel. A packet will not be forwarded out this interface unless the TTL in the packet exceeds this threshold.

  ratelimit

  This command provides a way to limit the rate of multicast traffic on an interface. It is an option in the XEROX PARC IP Multicast kernel (Release 3.3 or greater).

tunnel host lcladdr local_address dvrmp_parameters
  The tunnel statement uses the same dvmrp_parrameters as the interface statement.
traceoptions trace_options
  Specifies the tracing options for DVMRP. (See Trace Statements and the DVMRP specific tracing options below.)

## Tracing options

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

packets
  All DVMRP packets.
probe
  DVMRP Router Probe packets
report
  DVMRP Route Report packets
mapper
  DVMRP Neighbor and Neighbor 2 packets
prune
  DVMRP Prune packets
graft
  DVMRP Graft and Graft Ack packets

## Sample DVMRP configurations

See the sample multicast router configurations.

Last updated April 26, 1997.