Hi Eric, This seems to be caused by the below software bug.
CSCtq86186 - Switch stack shows incorrect values for output drops on show interfaces http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCtq86186 I've verified that this affects 15.0(1)SE3 and it'll be fixed in 15.0(2)SE. You can use the 'show platform port-asic stats drop' command to check hardware drop counters. Best regards, Andras On Wed, Aug 22, 2012 at 12:38 AM, Eric Van Tol <[email protected]> wrote: > Hi all, > I've got a pair of stacked 3750X switches running 15.0(1)SE3 and I'm noticing > something funky. On a pair of mirror destination ports, I'm seeing output > drops appear and disappear in the CLI output of 'show interface' at random > intervals. What I mean by this is, after clearing counters on all > interfaces, I can do a 'show int gi1/0/16' and see 'output drops 0' re-run > the command one second later and see 'output drops 39428200', then re-run the > command another second later and see 'output drops 0' again. I see it on > four monitor session destination ports. The problem started somewhat > randomly one day last week, after having working fine for two days prior > after being put into production use. > > Anyone ever seen this before? I'm pretty sure it's not just a cosmetic > issue, as the analyzer attached to these ports is seeing "packet loss" on the > traffic its analyzing, but I don't believe the source ports are actually > seeing any loss. > > Output is below - take note of the 'Last clearing of counters' times. > > -evt > > ~~~~~~~~~~~~~~ > vsw1-1213c.ss.sls.md#sh int gi2/0/17 > GigabitEthernet2/0/17 is up, line protocol is down (monitoring) > Hardware is Gigabit Ethernet, address is d48c.b549.4511 (bia d48c.b549.4511) > Description: VL Mirror Port > MTU 9198 bytes, BW 1000000 Kbit/sec, DLY 10 usec, > reliability 255/255, txload 1/255, rxload 1/255 > Encapsulation ARPA, loopback not set > Keepalive set (10 sec) > Full-duplex, 1000Mb/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 never, output never, output hang never > Last clearing of "show interface" counters 01:23:22 > Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 > Queueing strategy: fifo > Output queue: 0/40 (size/max) > 30 second input rate 0 bits/sec, 0 packets/sec > 30 second output rate 3868000 bits/sec, 2243 packets/sec > 0 packets input, 0 bytes, 0 no buffer > Received 0 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 > 24027518 packets output, 5217538085 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 > vsw1-1213c.ss.sls.md#sh int gi2/0/17 > GigabitEthernet2/0/17 is up, line protocol is down (monitoring) > Hardware is Gigabit Ethernet, address is d48c.b549.4511 (bia d48c.b549.4511) > Description: VL Mirror Port > MTU 9198 bytes, BW 1000000 Kbit/sec, DLY 10 usec, > reliability 255/255, txload 1/255, rxload 1/255 > Encapsulation ARPA, loopback not set > Keepalive set (10 sec) > Full-duplex, 1000Mb/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 never, output never, output hang never > Last clearing of "show interface" counters 01:23:23 > Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 39428034 > Queueing strategy: fifo > Output queue: 0/40 (size/max) > 30 second input rate 0 bits/sec, 0 packets/sec > 30 second output rate 3868000 bits/sec, 2243 packets/sec > 0 packets input, 0 bytes, 0 no buffer > Received 0 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 > 24027518 packets output, 5217538085 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 > vsw1-1213c.ss.sls.md#sh int gi2/0/17 > GigabitEthernet2/0/17 is up, line protocol is down (monitoring) > Hardware is Gigabit Ethernet, address is d48c.b549.4511 (bia d48c.b549.4511) > Description: VL Mirror Port > MTU 9198 bytes, BW 1000000 Kbit/sec, DLY 10 usec, > reliability 255/255, txload 1/255, rxload 1/255 > Encapsulation ARPA, loopback not set > Keepalive set (10 sec) > Full-duplex, 1000Mb/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 never, output never, output hang never > Last clearing of "show interface" counters 01:23:23 > Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 > Queueing strategy: fifo > Output queue: 0/40 (size/max) > 30 second input rate 0 bits/sec, 0 packets/sec > 30 second output rate 3868000 bits/sec, 2243 packets/sec > 0 packets input, 0 bytes, 0 no buffer > Received 0 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 > 24048581 packets output, 5222039119 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 > > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
