Foundry Switch and Router Installation and Configuration Guide
18 - 54 December 2000
Tracing the route for tree 209.157.23.188
0 207.95.7.2
0 207.95.7.2 Thresh 0
1 207.95.7.1 Thresh 0
2 207.95.8.1 Thresh 0
3 207.157.24.62
Syntax: mtrace source <ip-addr> group <multicast-group>
The source <ip-addr> parameter specifies the address of the route’s source.
NOTE: In IP multicasting, a route is handled in terms of its source, rather than its destination. When you trace
an IP route, you specify its destination, but when you trace a PIM route, you specify its source.
The group <multicast-group> parameter specifies the PIM group the source IP address is in.
Figure 18.9 shows an example of an IP multicast group. The command example shown above is entered on PIM
router A
Figure 18.9 Example PIM Group
The command example above indicates that the source address 209.157.24.62 is three hops (three PIM routers)
away from PIM router A. In PIM terms, each of the three routers has a forwarding state for the specified source
address and multicast group. The value following “Thresh” in some of the lines indicates the TTL threshold. The
threshold 0 means that all multicast packets are forwarded on the interface. If an administrator has set the TTL
threshold to a higher value, only packets whose TTL is higher than the threshold are forwarded on the interface.
The threshold is listed only for the PIM router hops between the source and destination.
USING THE WEB MANAGEMENT INTERFACE
You cannot trace a PIM route using the Web management interface.
Server
e3/19
Client
e1/4
207.95.7.1
Multicast group
239.255.162.1
e1/5
207.95.8.10
e3/11
Multicast group
239.255.162.1
PIM router C
PIM router A
e1/8
207.95.8.1
PIM router B
e2/3
207.95.7.2
8.8.8.164
209.157.24.62
BigIron BigIron BigIron
To Next Page
Loading...
