[c-nsp] carving TCAM on Engine 3 linecards due to exhausted IPv6 TCAM regions

[Jan Sandmaier]

Hi,

after some flux of IPv6 routes I got on my last old GSR the error
message for each line card:

%EE48-3-IPV6_TCAM_CAPACITY_EXCEEDED: IPv6 pkts will be software switched.

Issueing a "sh controllers frfab alpha tcam carve" shows me an
utilization of 50-100% of any RX_IPv6_* region while all other regions
have 0 to 5% utilization. I've no idea what the other regions exactly
are used for except Netflow.

Does anybody have experience in re-carving this TCAM?

Do I need to issue this command for each prefix lengh where a region
exists for or is there some magic command?

#hw-module slot 1 tcam carve RX_IPv6_144b_REGION ?
  <0-128>  Prefix length

#hw-module slot 1 tcam carve RX_IPv6_144b_REGION 128 ?
  <0-100>  percentage of TCAM

Thanks,
Jan


LC-Slot1#sh controllers frfab alpha tcam carve
Id  Region  % Curr/Carve/Dflt   Mask Blocks       Masks
Value Cells
                                 Total/Used(%)     Total/Used(%)
Total/Used(%)
-----------------------------------------------------------------------------
0  RX_TOP_NF	34.99/35.00/35.00 2867/0     0.00%  5734/0      0.00%
91744/0      0.00%
1  RX_TOP_72b	 0.98/ 1.00/ 1.00  324/0     0.00%   324/0      0.00%
2592/0      0.00%
2  RX_TOP_144b	 0.98/ 1.00/ 1.00   81/2     2.46%   162/5      3.08%
2592/80     3.08%
3  RX_TOP_288b	 0.98/ 1.00/ 1.00   20/0     0.00%    81/1      1.23%
2592/32     1.23%
4  RX_72b	 3.99/ 4.00/ 4.00 1308/0     0.00%  1308/0      0.00% 10464/0
     0.00%
5  RX_144b	19.99/20.00/20.00 1638/0     0.00%  3276/0      0.00% 52416/0
     0.00%
6  RX_288b	29.99/30.00/30.00  614/0     0.00%  2457/0      0.00% 78624/0
     0.00%
7  RX_IPv6_128	 0.04/ 4.00/ 4.00    4/4    100.00%     8/8     100.00%
 128/128   100.00%
8  RX_IPv6_127	 0.01/ 0.00/ 0.00    1/0     0.00%     2/1     50.00%
32/16    50.00%
9  RX_IPv6_126	 0.03/ 0.00/ 0.00    3/3    100.00%     6/6     100.00%
  96/96    100.00%
10 RX_IPv6_125	 0.01/ 0.00/ 0.00    1/0     0.00%     2/1     50.00%
32/16    50.00%
11 RX_IPv6_124	 0.01/ 0.00/ 0.00    1/0     0.00%     2/1     50.00%
32/16    50.00%
14 RX_IPv6_121	 0.01/ 0.00/ 0.00    1/0     0.00%     2/1     50.00%
32/16    50.00%
28 RX_IPv6_107	 0.01/ 0.00/ 0.00    1/0     0.00%     2/1     50.00%
32/16    50.00%
........


SLOT 1:Feb 17 03:45:29.567 GMT:
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)
SLOT 2:Feb 17 03:45:29.575 GMT: %EE48-3-IPV6_TCAM_CAPACITY_EXCEEDED:
IPv6 pkts will be software switched.