User's Manual

48-32
Switch(config)#interface vlan 1
Switch(Config-If-Vlan1)# ip pim sparse-mode
Switch(Config-If-Vlan1)#exit
Switch(config)#interface vlan 2
Switch(Config-If-Vlan2)# ip pim sparse-mode
Switch(Config-If-Vlan2)#exit
Switch(config)#interface vlan 3
Switch(Config-If-Vlan3)# ip pim sparse-mode
Switch(Config-If-Vlan3)#exit
Switch(config)#access-list 1 permit 224.1.1.1 0.0.0.255
Switch(config)#ip multicast ssm range 1
48.6.4 PIM-SSM Troubleshooting
In configuring and using PIM-SSM Protocol, PIM-SSM Protocol might not operate normally caused by
physical connection or incorrect configuration. Therefore, the user should pay attention to the following
issues:
 Assure that physical connection is correct;
 Assure the Protocol of Interface and Link is UP (use show interface command);
 Assure that PIM Protocol is enabled in Global Mode (use ip pim multicast-routing);
 Assure that PIM-SSM is configured on the interface (use ip pim sparse-mode);
 Assure that SSM is configured in Global Mode;
 Multicast Protocol requires RPF check using unicast routing, therefore the correctness of unicast
routing must be assured beforehand.
If all attempts including check are made but the problems on PIM-SSM can’t be solved yet, then use debug
commands such debug pim event/debug pim packet please, and then copy DEBUG information in 3
minutes and send to Technology Service Center.
48.7 DVMRP
48.7.1 Introduction to DVMRP
DVMRP Protocol, namely, is “Distance Vector Multicast Routing Protocol”. It is a Multicast Routing Protocol in
dense mode, which sets up a Forward Broadcast Tree for each source in a manner similar to RIP, and sets up
a Truncation Broadcast Tree, i.e. the Shortest Path Tree to the source, for each source through dynamic
Prune/Graft.
Some of the important features of DVMRP are:
1. The routing exchange used to determine reverse path checking information is based on distance
vector (in a manner similar to RIP)
2. Routing exchange update occurs periodically (the default is 60 seconds)
3. TTL upper limit = 32 hops (and that RIP is 16)
4. Routing update includes net mask and supports CIDR
In comparison with Unicast routing, Multicast routing is a kind of reverse routing (that is, what you are