PLANET XGS3-24042 - Manual (Page 416)

48-15
In configuring and using PIM-SM Protocol, PIM-SM 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-SM is configured on the interface (use ip pim sparse-mode);
 Multicast Protocol requires RPF Check using unicast routing; therefore the correctness of unicast
routing must be assured beforehand;
 PIM-SM Protocol requires supports by RP and BSR, therefore you should use show ip pim bsr-router
first to see if there is BSR information. If not, you need to check if there is unicast routing leading to
BSR.
 Use show ip pim rp-hash command to check if RP information is correct; if there is not RP information,
you still need to check unicast routing.
If all attempts including Check are made but the problems on PIM-SM can’t be solved yet, then use debug
commands such debug pim/debug pim BSR please, and then copy DEBUG information in 3 minutes and
send to Technology Service Center.
48.4 MSDP Configuration
48.4.1 Introduction to MSDP
MSDP – Multicast Source Discovery Protocol, is a protocol that can learn information about multicast source
in other PIM-SM domain. The RP on which MSDP is configured will advertise the information about the
multicast sources in its domain to all the other MSDP entities through SA messages. Thus, all the information
about multicast sources in one PIM-SM domain is spread to another. In MSDP, inter-domain information tree
is used other than the shared tree. It is required that the multicast routing protocol used for in-domain routing
must be PIM-SM.
 The work flow for RP in PIM-SM protocol
Multicast
Application Server
1 PIM Register
Packet
4 Switching to the
shortest path tree
and do the delivery
2 The subscriber
join the group
3 The
multicast
date is
deliveried
through the
shared tree
Subscriber
RP