PLANET XGS3-24040 - Manual (Page 380)

Chapter 43 Ipv4 Multicast Protocol
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capabilities of each other. If no Probe message from the neighbor is received until the neighbor is timed out,
then this neighbor is considered missing.
In DVMRP, source network routing selection message are exchanged in a basic manner same to RIP. That is,
routing report message is transmitted among DVMRP neighbors periodically (the default is 60 seconds). The
routing information in DVMRP routing selection table is used to set up source distribution tree, i.e. to
determine by which neighbor it passes to get to the source transmitting multicast packet; the interface to this
neighbor is called upstream interface. The routing report includes source network (use net mask) address and
the hop entry for routing scale.
In order to finish transmission correctly, every DVMRP switch needs to know which downstream switches
need to receive multicast packet from some specific source network through it. After receiving packets from
some specific source, DVMRP switch firstly will broadcast these multicast packets from all downstream
interfaces, i.e. the interfaces on which there are other DVMRP switches which have dependence on the
specific source. After receiving Prune message from some downstream switch on the interface, it will prune
this switch. DVMRP switch makes use of poison reverse to notify the upstream switch for some specific
source: “I am your downstream.” By adding infinity (32) to the routing distance of some specific source it
broadcasts, DVMRP switch responds to the source upstream exchange to fulfill poison reverse. This means
distance correct value is 1 to 2* infinity (32) -1 or 1 to 63, 1 to 63 means it can get to source network, 32
means source network is not arrival, 33 to 63 means the switch which generates the report message will
receive multicast packets from specific source depending on upstream router.
43.7.2 DVMRP Configuration Task List
1． Globally enable and disable DVMRP (Required)
2． Configure Enable and Disable DVMRP Protocol at the interface (Required)
3． Configure DVMRP Sub-parameters (Optional)
Configure DVMRP interface parameters
1) Configure the delay of transmitting report message on DVMRP interface and the message number
each time it transmits
2) Configure metric value of DVMRP interface
3) Configure if DVMRP is able to set up neighbors with DVMRP routers which can not Prune/Graft
4． Configure DVMRP tunnel
1. Globally enable DVMRP Protocol
The basic configuration to function DVMRP routing protocol on XGS3 series Layer 3 switch is very simple.
Firstly it is required to turn on DVMRP switch globally.
Command Explanation
Global Mode
[no] ip dvmrp multicast-routing
Globally enable DVMRP Protocol, the “no ip
dvmrp multicast-routing” command disables
DVMRP Protocol globally. (Required)