Configuring A Dvmrp Tunnel - Cisco WS-C3750-48PS-S Software Configuration Manual

Chapter 36 Configuring IP Multicast Routing
This example shows how to configure DVMRP interoperability when the PIM device and the DVMRP
router are on the same network segment. In this example, access list 1 advertises the networks
(198.92.35.0, 198.92.36.0, 198.92.37.0, 131.108.0.0, and 150.136.0.0) to the DVMRP router, and access
list 2 prevents all other networks from being advertised (ip dvmrp metric 0 interface configuration
command).
Switch(config-if)# interface gigabitethernet1/0/1
Switch(config-if)# ip address 131.119.244.244 255.255.255.0
Switch(config-if)# ip pim dense-mode
Switch(config-if)# ip dvmrp metric 1 list 1
Switch(config-if)# ip dvmrp metric 0 list 2
Switch(config-if)# exit
Switch(config)# access-list 1 permit 198.92.35.0 0.0.0.255
Switch(config)# access-list 1 permit 198.92.36.0 0.0.0.255
Switch(config)# access-list 1 permit 198.92.37.0 0.0.0.255
Switch(config)# access-list 1 permit 131.108.0.0 0.0.255.255
Switch(config)# access-list 1 permit 150.136.0.0 0.0.255.255
Switch(config)# access-list 1 deny
Switch(config)# access-list 2 permit 0.0.0.0 255.255.255.255

Configuring a DVMRP Tunnel

The software supports DVMRP tunnels to the MBONE. You can configure a DVMRP tunnel on a router
or multilayer switch if the other end is running DVMRP. The software then sends and receives multicast
packets through the tunnel. This strategy enables a PIM domain to connect to the DVMRP router when
all routers on the path do not support multicast routing. You cannot configure a DVMRP tunnel between
two routers.
When a Cisco router or multilayer switch runs DVMRP through a tunnel, it advertises sources in
DVMRP report messages, much as it does on real networks. The software also caches DVMRP report
messages it receives and uses them in its RPF calculation. This behavior enables the software to forward
multicast packets received through the tunnel.
When you configure a DVMRP tunnel, you should assign an IP address to a tunnel in these cases:
•
•
The software does not advertise subnets through the tunnel if the tunnel has a different network number
from the subnet. In this case, the software advertises only the network number through the tunnel.
78-16180-02
To send IP packets through the tunnel
To configure the software to perform DVMRP summarization
Configuring Basic DVMRP Interoperability Features
0.0.0.0 255.255.255.255
Catalyst 3750 Switch Software Configuration Guide
36-39