The ICAM is used to handle hash collisions in the netflow table. It essentially indicates that 2 unique flows hashed to the same key in the hardware, so the netflow TCAM stores the index to the flow info for one flow, and the ICAM (aka alias CAM) stores the index to the second.

If there are no free entries in the TCAM, or there is already an alias entry for a hash key in both the TCAM & ICAM, then you will see creation failures. Use the "aggregate" keyword to see the cumulative count - the "detail" output is clear on read for the last two values, so enter several iterations to see if the creation failures/aliasing is happening continuously.

The ICAM is relatively small, it has 128 entries only. In general the hash efficiency on 3BXL should give you very good table utilization.

show mls netflow table-contention detail

show mls netflow table-contention aggregate