Configuring Dvmrp Tunnels; Important Considerations - 3Com 4007 Implementation Manual

Configuring DVMRP
Tunnels
Important
Considerations
Table 79 lists conventional numeric values and network objectives.
Table 79 Conventional TTL Scope Control Values
TTL Value Objective
0 Restricted to the same host
1 Restricted to the same subnetwork
16 Restricted to the same site
64 Restricted to the same region
128 Restricted to the same continent
255 Unrestricted in scope
A DVMRP tunnel allows IP multicast packets to traverse a portion of your
network infrastructure that is not multicast-aware. In Multilayer
Switching Modules, you can define tunnels, modify tunnel characteristics,
display information about tunnels you have defined, and remove tunnels.
All networks do not require DVMRP tunnels. A network needs a
tunnel only if IP multicast packets must go through one or more
unicast routers to reach IP multicast group members.
You can configure any routing interface on a Multilayer Switching
Module to be a DVMRP tunnel end point. The other tunnel end point
must be a multicast interface on a different system and subnetwork.
Before you can define a tunnel end point, you must configure a
routing interface and enable DVMRP on the interface. Think of a
tunnel end point as being layered on top of an existing IP multicast
routing interface.
The maximum number of IP multicast tunnels that you can define on a
Switch 4007 Multilayer Switching Module is 8.
To define a tunnel, you specify the following tunnel characteristics:
The index number of the local router interface that serves as the
tunnel end point.
The IP address of the destination multicast router. This address
must be a remote address. The destination multicast router cannot
be directly connected to the same subnetwork.
When you define a tunnel, the module assigns tunnel metric and
tunnel TTL threshold values of 1. You can modify these at any time.

Configuring DVMRP Tunnels

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