06-03-2008 01:29 PM - edited 03-05-2019 11:24 PM
#show platform port-asic stats drop
showing some packet drops, what is the implication of the result? Should I concerned anything? I did not clear the counter for two monthes.
Thanks,
Port-asic Port Drop Statistics - Summary
========================================
RxQueue 0 Drop Stats: 0
RxQueue 1 Drop Stats: 0
RxQueue 2 Drop Stats: 0
RxQueue 3 Drop Stats: 0
Port 0 TxQueue Drop Stats: 0
Port 1 TxQueue Drop Stats: 0
Port 2 TxQueue Drop Stats: 3298
Port 3 TxQueue Drop Stats: 0
...............................
Port 2 TxQueue Drop Statistics
Queue 0
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 0
--More-- Queue 1
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 0
Queue 2
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 0
Queue 3
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 3298
06-03-2008 02:12 PM
Should you be concerned? It depends....
Check what DSCP & CoS values map to threshold 3 of the 4th queue as that is the only one that has dropped any frames (show mls qos maps). I haven't got a 3560/3750 to hand so I don't know what this is by default, although I have a feeling by default nothing maps to the 3rd threshold of any queue.
3298 frames over two months doesn't sound a lot to me, however if the network is not loaded at any time then it is possible the queue thresholds/sizes need tuning.
Andy
06-03-2008 08:47 PM
Actually he should be concerned ...I am not a QOS expert but , a misconfigured QOS can cause asic level drops ... you may try to disable qos on all the interfaces that are using this asic .
After that please check if the drops are still incrementing or not .
If its not because of QOS then this is a hardware issue , asic limitation .
06-04-2008 08:39 AM
It may be the desired behaviour - i.e. congestion avoidance. The 3560/3750 uses congestion avoidance (random dropping) when thresholds are being reached in queues, this can be a desired behaviour to slow down flows if TCP traffic is mapped to that queue/threshold.
Andy
06-04-2008 10:43 AM
We had a similar issue due to a misconfigured QoS and had to tweak the thresholds to rectify it.
Check whether the counters are increasing as you cannot clear them without a reload.
HTH
Narayan
01-16-2012 02:00 AM
Hi
We don't have any QoS in use, but I see a high number of drops when the load increases to over 600Mbit/s on that interface. See:
show platform port-asic stats drop g1/0/26
Interface Gi1/0/26 TxQueue Drop Statistics
Queue 0
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 0
Queue 1
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 0
Queue 2
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 0
Queue 3
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 3529272
Queue 4
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 0
Queue 5
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 0
Queue 6
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 0
Queue 7
Weight 0 Frames 0
Weight 1 Frames 0
Weight 2 Frames 0
And here the interface:
sh int g1/0/26
GigabitEthernet1/0/26 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 0026.9981.e11a (bia 0026.9981.e11a)
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 17/255, rxload 2/255
Encapsulation ARPA, loopback not set
Keepalive not set
Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX SFP
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:04, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:19:07
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 150
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 10629000 bits/sec, 6922 packets/sec
5 minute output rate 67813000 bits/sec, 10457 packets/sec
16633696 packets input, 2137400609 bytes, 0 no buffer
Received 111580 broadcasts (56109 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 56109 multicast, 0 pause input
0 input packets with dribble condition detected
28212625 packets output, 35494347176 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 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
sh mls qos
QoS is disabled globally
sh int g1/0/26
GigabitEthernet1/0/26 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 0026.9981.e11a (bia 0026.9981.e11a)
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 17/255, rxload 2/255
Encapsulation ARPA, loopback not set
Keepalive not set
Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX SFP
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:04, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:19:07
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 150
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 10629000 bits/sec, 6922 packets/sec
5 minute output rate 67813000 bits/sec, 10457 packets/sec
16633696 packets input, 2137400609 bytes, 0 no buffer
Received 111580 broadcasts (56109 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 56109 multicast, 0 pause input
0 input packets with dribble condition detected
28212625 packets output, 35494347176 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 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
sh mls qos
QoS is disabled globally
It's actually in a portchannel with a second interface, which doesn't show any errors.
Could that be a broken hardware?
It's a stack consisting of two WS-C3750E-24TD with software 12.2(58)SE1.
Thanks
05-19-2017 09:37 AM
Interestingly we have the same build version on 3750-x stack and observing crazy amount of packet discards on some interfaces.
05-19-2017 12:54 PM
Without QoS enabled?
Even without QoS, I suspect the 3750 likely does its interface buffer management similar as it does with QoS, but probably w/o reservations per interface egress queues.
If had some fantastic success with QoS enabled and after buffer tuning. I.e. had a couple of SAN ports having multiple drops per second, after buffer tuning, just a few drops per day.
What I did was place almost all the buffers into the shared/common pool, i.e. stopped buffers being reserved per interface egress queue. Also increased what an interface was allowed to dynamically allocate from the shared/common pool. (Of course, understand, this better supports just a few ports with large micro bursts while other ports don't need buffers.)
05-22-2017 10:52 AM
Thanks for the great Info and reply.
Do you think Updating the firmware to a more recent one will fix this?
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