Multicast troubleshooting

PIM Multicast 

Problem : Multicast source is not getting register with RP.
Cause :
Solution:

Problem : RPF failing for the multicast .
Cause :
Solution:



Problem : Multicast is not switching to shortest path tree.
Cause :
Solution: 

IGMP Multicast

Problem : Multicast traffic is flooding.
Cause :
1. IGMP snooping disabled
2. IGMP snooping enabled but no mrouter present.
3. IGMP snooping enabled but IGMP snooping table is empty.

Solution:
a) Make sure IGMP snooping is enabled.
b) IGMP querier is configured .
c) Find out if only source is connected in the vlan and no receiver.
d) If any IGMP version mismatch V1 or V2.


Problem : IGMP Multicast is not working where source and receiver are in same vlan.
Cause :
1. No Mrouter configured.
2. No IGMP querier is configured.
3. No PIM sparse-dense mode command creating mrouter port and IGMP querier.

Solution:
a) Enable the igmp querier on layer 2 switch.
b) Configure the "ip pim sparse-dense mode" on SVI.