All things related to multicast

[John Meylor <>]

Philip Ho wrote:
> 
> Hello all,
> 
> Looking for your help in a multicast error in Cisco switch.
> 
> Critical error message is found when I pumped single source with 1000
> groups of multicast data through Catalyst 6509. Version is 6.2(3).
> 
> Error message:
> %MCAST-2-MAXGDALIMIT:No. of Multicast entries has reached the max 3072
> 
> I suppose even (*,G) and (S,G) exists, there are only 2000 entries. Does
> catalyst 6000 really has the limit of 3072 multicast entries? Has anyone
> in Internet2 experienced this problem before? What is the maximum number
> of multicast enties you have seen in a 6509?

Philip,

- the message only implies that the max number of entries in mac table,
    for IGMP snooping has been reached, other mcast groups are 
    still forwarded, but they are flooded within the subnet.
 - CatOs supports upto 15k L2 entries in 6.3(2) and higher releases
 - Native IOS supports upwards of 13K L2 entries from day-1.

Remember these L2 entries are different than the number of
L3 entries which can be supported on the box, the numbers
for those are much larger, depending on the hw config of
the box.

BTW, we noticed that the current numbers aren't well documented
on current CCO pages, so those should be updated by sometime tomorrow.

 John