Re: 2960 queue drops

network1215 · ‎10-16-2019

Hi,

I am looking at out "show mls qos int gig 1/0/12 statistics" and wonder if should be concerned about the outs in "

output queues dropped" at the bottom of output.

There is qos enabled.

Q: how do I identify which packets getting dropped ? looking at "output queues dropped"

Q: I did see "Total output drops" on this interface in numbers "8829" but cleared the interface counters, now see 0 drops ? is this relevant to "output queues dropped"

GigabitEthernet1/0/12 (All statistics are in packets)

dscp: incoming

-------------------------------

0 - 4 : 61531446 0 0 0 0

5 - 9 : 0 0 0 0 0

10 - 14 : 15716 0 0 0 0

15 - 19 : 0 0 0 0 0

20 - 24 : 0 0 0 0 0

25 - 29 : 0 11900048 0 0 0

30 - 34 : 0 0 786481 0 0

35 - 39 : 0 0 0 0 0

40 - 44 : 0 0 0 0 0

45 - 49 : 0 35380561 0 0 0

50 - 54 : 0 0 0 0 0

55 - 59 : 0 0 0 0 0

60 - 64 : 0 0 0 0

dscp: outgoing

-------------------------------

0 - 4 : 8988344 22094 367300 16 154664

5 - 9 : 2 43 7 10066779 0

10 - 14 : 133785 1 1 1 36

15 - 19 : 2 364 0 652 8

20 - 24 : 16 6 2 2 9572

25 - 29 : 5 19272391 63 4 5

30 - 34 : 3 10 716074 6 2

35 - 39 : 19 38 0 2923 0

40 - 44 : 9 5 16 0 214

45 - 49 : 2 33596334 2 41570000 1

50 - 54 : 0 22 1 4 24

55 - 59 : 5 165835 4 4 2

60 - 64 : 9 3 3 0

cos: incoming

-------------------------------

0 - 4 : 421002324 0 0 8712888 0

5 - 7 : 28608651 0 0

cos: outgoing

-------------------------------

0 - 4 : 1604303796 707487 74346632 2382218 12776147

5 - 7 : 20089626 68293948 30691975

output queues enqueued:

queue: threshold1 threshold2 threshold3

-----------------------------------------------

queue 0: 0 0 791100

queue 1: 260896088 385956391 132126554

queue 2: 0 0 11110999

queue 3: 183863 257 1107952031

output queues dropped:

queue: threshold1 threshold2 threshold3

-----------------------------------------------

queue 0: 0 0 0

queue 1: 2484 0 0

queue 2: 0 0 11683

queue 3: 1002 0 382426

Policer: Inprofile: 1817873 OutofProfile: 1132

=======================

show int gig 1/0/12

======================

GigabitEthernet1/0/12 is up, line protocol is up (connected)

Hardware is Gigabit Ethernet, address is 84b5.1782.7444 (bia 84b5.1782.7444)

MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s, media type is 10/100/1000BaseTX

input flow-control is off, output flow-control is unsupported

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:08, output 00:00:01, output hang never

Last clearing of "show interface" counters 00:02:00

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 30000 bits/sec, 33 packets/sec

29 packets input, 4098 bytes, 0 no buffer

Received 6 broadcasts (6 multicasts)

0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 6 multicast, 0 pause input

0 input packets with dribble condition detected

4157 packets output, 485267 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

4 unknown protocol drops

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier, 0 pause output

0 output buffer failures, 0 output buffers swapped out

paul driver · ‎10-16-2019

Hello

Possible historical - Can you post the output of the following:

sh mls qos queue-set
sh mls qos input-queue
sh mls qos interface gig1/0/12 queuing

Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

network1215 · ‎10-16-2019

sh mls qos input-queue (didn't work)

!

sh mls qos queue-set

Queueset: 1

Queue : 1 2 3 4

----------------------------------------------

buffers : 15 30 45 10

threshold1: 60 80 100 100

threshold2: 100 90 100 100

reserved : 100 100 50 50

maximum : 400 400 400 400

Queueset: 2

Queue : 1 2 3 4

----------------------------------------------

buffers : 25 25 25 25

threshold1: 100 200 100 100

threshold2: 100 200 100 100

reserved : 50 50 50 50

maximum : 400 400 400 400

sh mls qos interface gig1/0/12 queueing

GigabitEthernet1/0/12

Egress Priority Queue : enabled

Shaped queue weights (absolute) : 15 0 0 0

Shared queue weights : 1 15 30 15

The port bandwidth limit : 100 (Operational Bandwidth:100.0)

The port is mapped to qset : 1

in addition below is the configuration:

mls qos srr-queue output cos-map queue 1 threshold 3 4 5
mls qos srr-queue output cos-map queue 2 threshold 1 2
mls qos srr-queue output cos-map queue 2 threshold 2 3
mls qos srr-queue output cos-map queue 2 threshold 3 6 7
mls qos srr-queue output cos-map queue 3 threshold 3 0
mls qos srr-queue output cos-map queue 4 threshold 3 1
!
mls qos srr-queue output dscp-map queue 1 threshold 3 32 34 40 46
mls qos srr-queue output dscp-map queue 2 threshold 1 16 18 20 22 26 28 30 36
mls qos srr-queue output dscp-map queue 2 threshold 1 38
mls qos srr-queue output dscp-map queue 2 threshold 2 24
mls qos srr-queue output dscp-map queue 2 threshold 3 48 56
mls qos srr-queue output dscp-map queue 3 threshold 3 0
mls qos srr-queue output dscp-map queue 4 threshold 1 8
mls qos srr-queue output dscp-map queue 4 threshold 2 10 12 14
!
mls qos queue-set output 1 threshold 1 60 100 100 400
mls qos queue-set output 1 threshold 2 80 90 100 400
!
mls qos queue-set output 1 buffers 15 30 45 10
!

thanks Paul

network1215 · ‎10-18-2019

curious if you did get a chance to look into configuration

Joseph W. Doherty · ‎10-18-2019

". . . wonder if should be concerned about the outs in output queues dropped" at the bottom of output."

Concerned? That depends. Generally it's worth determining if drops are detrimental to your network applications who are losing those packets. However, also generally, very low drop rates are not detrimental. Drop rate impact does vary between network applications.

"Q: how do I identify which packets getting dropped ? looking at "output queues dropped""

That depends on you "knowing" what traffic gets into the queues which are accumulating drops.

"Q: I did see "Total output drops" on this interface in numbers "8829" but cleared the interface counters, now see 0 drops ? is this relevant to "output queues dropped" "

On low-end switches, interface drop stats don't always reflect ASIC drops. (Sometimes ASIC stats have errors too.) Using a "solid" IOS version is your best bet for accurate stats.