[c-nsp] TCAM carving for IPv6

[Aaron Daubman]

Greetings,

I just received this error for the first time and was looking for
pointers as to how best re-carve TCAM.

"""
SLOT 0:Jul 17 12:04:49.815 EDT: %EE48-3-IPV6_TCAM_CAPACITY_EXCEEDED:
IPv6 pkts will be software switched.
To support more IPv6 routes in hardware:
Get current TCAM usage with: show controllers ISE <slot> tcam
In config mode, reallocate TCAM regions e.g. reallocate Netflow TCAM to IPv6
 hw-module slot <num> tcam carve rx_ipv6_1 <prefix> <v6-percent>
 hw-module slot <num> tcam carve rx_top_nf <nf-percent>
Verify with show command that sum of all TCAM regions = 100%
Reload the linecard for the new TCAM carve config to take effect
WARNING: Recarve may affect other input features(ACL,CAR,MQC,Netflow)
"""

E.g. - if I know I will be supporting at most 5-10 v4 routes, but 10s
to 100s of 1000s of v6 routes, what areas should I de-allocate and
re-allocate...
Also, if we won't be using Netflow at all...

(I'd also need a basic TCAM primer on what the differences in TX and
RX are in general as well as RX_IPv6_128 vs RX_IPv6_1 and RX_72b vs
RX_144b etc..)

A nice breakdown of the different TCAM regions, ones to consider
adjusting, gotchas of dropping an assumed unnecessary region to 0%,
areas to stay away from, etc... would be great.

TIA,
     ~Aaron