08-23-2012 03:11 PM - edited 03-07-2019 08:30 AM
Hi there,
We are getting some packet drops on our some 2960 switchs.
sh int f0/27 | inc drops|bits
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 10297
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 6000 bits/sec, 3 packets/sec
And users are complaining about slow network and taking long to open any network drives.
It’s a (C2960-HBOOT-M) Version 12.2(46r)SE2 lanbasek9-mz.122-55.SE3.bin
But there is not much traffic going trough and we still getting drops
FastEthernet0/27 is up, line protocol is up (connected)
Hardware is Fast Ethernet, address is
Description: Level 11 VoIP and Data Connection
MTU 1500 bytes, BW 100000 Kbit, 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 10/100BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 2w0d, output 00:00:00, output hang never
Last clearing of "show interface" counters 1w3d
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 10297
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 3000 bits/sec, 3 packets/sec
5 minute output rate 30000 bits/sec, 7 packets/sec
408520 packets input, 102710312 bytes, 0 no buffer
Received 220 broadcasts (0 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 0 multicast, 0 pause input
0 input packets with dribble condition detected
1695780 packets output, 686477375 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
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 int f0/27 counters errors
Port Align-Err FCS-Err Xmit-Err Rcv-Err UnderSize OutDiscards
Fa0/27 0 0 0 0 0 10297
Please help.
thanks
08-26-2012 09:46 PM
Hi Amrinder,
These outdiscards counters indicate that the switch could not buffer all the packets that came in on that port a that moment of time, which happens when the traffic is bursty in nature
Please change the load interval from 5 mins to 30 secs and it does not cause anything to work differently. By setting the load-interval to a shorter value you may see more easily the impact of bursty traffic which is one of the cause for output drops
Ex:
Switch(Config)#int fa0/27
Switch(Config-if)#load-interval 30
Switch(Config-if)#exit
What type of interface fa0/27 it is?
do you see this output drops continuously or intermittent?
is the mls qoq enabled?
Clear the counter and verify the below commands, and check does the output drops incrementing continuously
#show int f0/27 | inc drops|bits
#show int f0/27 counters errors
#show mls qos int <interfa-id> statistics
#show platform port-asic stats drop fa0/7
#sh controllers ethernet-controller fa0/7
Regards,
Aru
08-27-2012 01:48 PM
Hi Arumugam ,
thanks for helping me out here.
we changed the interval to 30 seconds.
Actually, this is a voice and data port. Therefore, we remove the voice vlan to see if it stop packet drop. However, the thing is user complaining slow network as well. I am monitoring the port in cacti and drops are around 6 am in the morning and no one was in office.
So at end we remove the qos config from this port to see if we still getting drops.
Drops are not continuously they just intermittent.
There was no traffic going through and in the morning and we still getting drops.
any idea??
thanks for your help.
08-26-2012 09:50 PM
Duplicate post #2.
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