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Cisco Catalyst Blade Switch 3130 for Dell Software Configuration Guide
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Chapter44 Configuring IP Multicast Routi ng Configuring Basic DVMRP Interoperability Features
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 softw are 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 conf igure 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:
•To send IP packets through the tunnel
•To configure the software to perform DVMRP summarization
The software does not advertise subnets through the tunnel if the tu nnel has a different network number
from the subnet. In this case, the software advertises only the network number through the tunnel.
Beginning in privileged EXEC mode, follow these steps to configure a DVMRP tunnel. This procedu re
is optional.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 access-list access-list-number {deny |
permit} source [source-wildcard]Create a standard access list, repeating the command as many times as
necessary.
•For access-list-number, the range is 1 to 99.
•The deny keyword denies access if the conditions are matched. The
permit keyword permits access if the conditions are matched.
•For source, enter the number of the network or host from which the
packet is being sent.
•(Optional) For source-wildcard, enter the wildcard bits in dotted
decimal notation to be applied to the source. Place ones in the bit
positions that you want to ignore.
Recall that the access list is always terminated by an implicit deny
statement for everything.
Step3 interface tunnel number Specify a tunnel interface, and enter interface configuration mode.
Step4 tunnel source ip-address Specify the source address of the tunnel interface. Enter the IP address
of the interface on the switch.
Step5 tunnel destination ip-address Specify the destination address of the tunnel interface. Enter the IP
address of the mrouted router.
Step6 tunnel mode dvmrp Configure the encapsulation mode for the tunnel to DVMRP.
Step7 ip address address mask
or
ip unnumbered type number
Assign an IP address to the interface.
or
Configure the interface as unnumbered.
Step8 ip pim [dense-mode | sparse-mode] Configure the PIM mode on the interface.