6.3.2 Multicast Routing Protocols

6.3.2.1 The DVMRP statement

The DVMRP statement is used to configure DVMRP. GateD-5.0 is compliant with the DVMRPv3 spec.

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.

DVMRP has both "tree construction" and "route" passage functions. The DVMRP "routes" are loaded into the multicast RIB under import policy and exported using export policy.


Syntax

   dvmrp ( yes | no | on | off | routing-only ) {
      interface interface_list {
         enable | disable | routing-only ;
         nodvmrpout ;
         noretransmit ;
         metric metric ;
      };
      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. dvmrp routing-only specifies that DVMRP will be used only to propagate the multicast RIB, but that it will not be used for tree construction. This may be used to let DVMRP carry the multicast RIB which is then used by PIM-SM.

The options are as follows:

interface interface_list


Tracing Options

traceoptions trace_options

   Specifies the tracing options for DVMRP.  (See Trace Statements and the
   DVMRP specific tracing options below.)

   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