Avaya 8800 Troubleshooting Manual page 372

Multicast feature troubleshooting
• If a route is available in both the unicast routing table and the multicast static IP route
table, then the route from the multicast static IP route table is used only if its administrative
distance is less than or equal to that of the unicast route entry.
• The configured static-mroute is selected in the following manner:
- First longest prefix matching route is selected. The lookup ignores routes that are
administratively disabled.
- If the table has more than one matching route for the same destination, then the
route with the least preference value is selected.
- If more than one route has the same preference value, then the route with the higher
RPF address is selected.
- Finally, the selected static-mroute preference is compared to RTM route preference,
and if the RTM route has the least preference, then the RTM route is selected.
Possible reasons for a configured static mroute not being chosen include:
• The selected route is the direct route.
• The route is not the matching route for the destination.
• The route is not reachable or disabled in the multicast route table.
• The RPF address is not a PIM neighbor.
• The route preference is greater than the RTM route.
Procedure steps
If all the preceding conditions are satisfied and a configured static mroute is not chosen, you
can use the following procedure to troubleshoot the problem.
1. To verify whether the configured static-mroute is selected or not, enter the following
372 Troubleshooting
CLI command:
show ip mroute rpf <A.B.C.D>
OR
enter the following ACLI command:
show ip static-mroute rpf <A.B.C.D>
This command shows the best route to the RP or source from the static-mroute or
unicast routing table. If the multicast route is not the selected route, then note the
preference value of the selected route.
The following sample output shows that the route to destination 20.20.20.2 takes a
unicast route.
8600# show ip mroute rpf
Comments? infodev@avaya.com
July 2013