Chapter 42 Configuring IP Multicast Routing

Configuring Advanced DVMRP Interoperability Features

Beginning in privileged EXEC mode, follow these steps to advertise network 0.0.0.0 to DVMRP neighbors on an interface. This procedure is optional.

 

Command

Purpose

Step 1

 

 

configure terminal

Enter global configuration mode.

Step 2

 

 

interface interface-id

Specify the interface that is connected to the DVMRP router, and enter

 

 

interface configuration mode.

Step 3

 

 

ip dvmrp default-information

Advertise network 0.0.0.0 to DVMRP neighbors.

 

{originate only}

Use this command only when the switch is a neighbor of mrouted

 

 

 

 

Version 3.6 machines.

 

 

The keywords have these meanings:

 

 

originate—Specifies that other routes more specific than 0.0.0.0 can

 

 

also be advertised.

 

 

only—Specifies that no DVMRP routes other than 0.0.0.0 are

 

 

advertised.

Step 4

 

 

end

Return to privileged EXEC mode.

Step 5

 

 

show running-config

Verify your entries.

Step 6

 

 

copy running-config startup-config

(Optional) Save your entries in the configuration file.

 

 

 

To prevent the default route advertisement, use the no ip dvmrp default-informationinterface configuration command.

Responding to mrinfo Requests

The software answers mrinfo requests sent by mrouted systems and Cisco routers and multilayer switches. The software returns information about neighbors through DVMRP tunnels and all the routed interfaces. This information includes the metric (always set to 1), the configured TTL threshold, the status of the interface, and various flags. You can also use the mrinfo privileged EXEC command to query the router or switch itself, as in this example:

Switch# mrinfo

171.69.214.27 (mm1-7kd.cisco.com) [version cisco 11.1] [flags: PMS]: 171.69.214.27 -> 171.69.214.26 (mm1-r7kb.cisco.com) [1/0/pim/querier] 171.69.214.27 -> 171.69.214.25 (mm1-45a.cisco.com) [1/0/pim/querier] 171.69.214.33 -> 171.69.214.34 (mm1-45c.cisco.com) [1/0/pim] 171.69.214.137 -> 0.0.0.0 [1/0/pim/querier/down/leaf] 171.69.214.203 -> 0.0.0.0 [1/0/pim/querier/down/leaf] 171.69.214.18 -> 171.69.214.20 (mm1-45e.cisco.com) [1/0/pim] 171.69.214.18 -> 171.69.214.19 (mm1-45c.cisco.com) [1/0/pim] 171.69.214.18 -> 171.69.214.17 (mm1-45a.cisco.com) [1/0/pim]

Configuring Advanced DVMRP Interoperability Features

Cisco routers and multilayer switches run PIM to forward multicast packets to receivers and receive multicast packets from senders. It is also possible to propagate DVMRP routes into and through a PIM cloud. PIM uses this information; however, Cisco routers and multilayer switches do not implement DVMRP to forward multicast packets.

 

 

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

 

 

 

 

 

 

OL-9775-02

 

 

42-43

 

 

 

 

 

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Cisco Systems 3750E Configuring Advanced Dvmrp Interoperability Features, Responding to mrinfo Requests, Originate only