TS for 6748 output drop
When you found have output queue drop for CEF720 LC, you can check follow step:
1. which port have issue, whether at same ASIC.
2. check whether have other error or have qos on issue port.
3. whether hw queue is full.
Follow is TS example:
Problem description:
Output queue have drop
1. After checked by follow command:
– show tech
– show inter switching x/x
– show int x/x counter de
– show inter x/x summary
Found not one ASIC have issue (6748 is one ASCI each 12 port).
Only one vlan have issue, but traffics not amount.
2. Suspect burst traffics lead to queue full, check by follow command
– show queueing int gx/x
Found customer config mls qos, and packets drop at queue1.
(At 6748, Tx port buffer is 1.164MB)
7609#show queueing int g7/14
Interface GigabitEthernet9/13 queueing strategy: Weighted Round-Robin
Port QoS is enabled
Port is untrusted
Extend trust state: not trusted [COS = 0]
Default COS is 0
Queueing Mode In Tx direction: mode-cos
Transmit queues [type = 1p3q8t]:
Queue Id Scheduling Num of thresholds
-----------------------------------------
01 WRR 08
02 WRR 08
03 WRR 08
04 Priority 01
WRR bandwidth ratios: 100[queue 1] 150[queue 2] 200[queue 3]
queue-limit ratios: 50[queue 1] 20[queue 2] 15[queue 3] 15[Pri Queue]
Packets dropped on Transmit:
queue dropped [cos-map]
---------------------------------------------
1 3333 [0 1 ]
2 0 [2 3 4 ]
3 0 [6 7 ]
4 0 [5 ]
Base on the information, Queue1 only have 100/(100+150+200)=22% WRR bandwidth.
And queue-limit only have 50%.
( Refer to wrr bandwidth and queue-limit, please reference <Catalyst QOS Campus Network> )
So change wrr queue or no mls qos.
After no mls qos, found drop not disappear, all queue resources in queue1.
And found have burst in issue vlan.
YZ_iTV2.0_R1.C7609_A#show queueing interface g9/13 Interface GigabitEthernet9/13 queueing strategy: Weighted Round-Robin QoS is disabled globally Trust state: trust DSCP Extend trust state: not trusted [COS = 0] Default COS is 0 Queueing Mode In Tx direction: mode-cos Transmit queues [type = 1p3q8t]: Queue Id Scheduling Num of thresholds ----------------------------------------- 01 WRR 08 02 WRR 08 03 WRR 08 04 Priority 01 WRR bandwidth ratios: 100[queue 1] 0[queue 2] 0[queue 3] queue-limit ratios: 100[queue 1] 0[queue 2] 0[queue 3] 0[Pri Queue] Packets dropped on Transmit: queue dropped [cos-map] --------------------------------------------- 1 2499 [0 1 2 3 4 5 6 7 ] 2 0 [] 3 0 [] 4 0 []
Follow is information that check port buffer:
(config-if)#do remote command switch show qm port 6 2
-----------------------------------------------------------------------------
* Type: Tx[1p2q2t] Rx[1p1q4t] [0] Pinnacle
* Per-Port: [Untrusted] Default COS[0] force[0] [VLAN based]
-----------------------------------------------------------------------------
* COSMAP(C[Q/T]) TX: 0[1/1] 1[1/1] 2[1/2] 3[1/2] 4[2/1] 5[3/1] 6[2/1] 7[2/2]
RX: 0[1/1] 1[1/1] 2[1/1] 3[1/1] 4[1/1] 5[1/1] 6[1/1] 7[1/1]
-----------------------------------------------------------------------------
* WRR bandwidth: [25344 544]
* TX queue limit(size): [409600 16384 16384]
* WRED queue[1]: wredLowThr[163840 286720] wredThr[286720 409472] rndNumber[0]
AveWeight[128] SampleCntr[255] PktCntr[0] QFreecnt[1073746944]
queue[2]: wredLowThr[6553 11468] wredThr[11520 12288] rndNumber[0]
AveWeight[128] SampleCntr[255] PktCntr[0] QFreecnt[1073741824]
-----------------------------------------------------------------------------
* TX drop thr queue[1]: type[2 QOS_SCP_2_THR] dropThr[286720 409472]
queue[2]: type[2 QOS_SCP_2_THR] dropThr[11520 12288]
* RX drop threshold: type[4 QOS_SCP_4_THR] dropThr[65536 65536 65536 65536]
* RXOvr drop threshold: type[20 UNSUPPORTED]
* TXOvr drop threshold: type[20 UNSUPPORTED]