Re: Interface input drops on 6506

Graham Murison · ‎01-09-2019

I am getting input drops on my 6506-E. I beleive it is probably due to the MTU mismatch, however I would like someone in the community confirming that for me.
Yes I know the IOS is REALLY old, but it is all I have to work with. The 6506 was recently configured as our default gateway an now just about all network traffic has slowed terrbily.
The CPU and memory seem fine and logging doesn't seem to be indicating any major issues.
I have gone thrugh this document and it hasn't really helped: https://www.cisco.com/c/en/us/support/docs/routers/10000-series-routers/6343-queue-drops.htm

Georg Pauwen · ‎01-09-2019

Hello,

can you post the output of:

sh int gig 6/1 counters detail

Also, what do you have connected to that port, 6/1 ? Make sure speed and duplex match on both sides, your side is set to fixed 1000 full duplex, whatever is connected should also be set to that.

Graham Murison · ‎01-10-2019

Thanks for the reply.

Unfortunately the detail sub-command doesn't exist in this version of IOS, so I posted the closest:

sh int gig 6/1 counters

Port InOctets InUcastPkts InMcastPkts InBcastPkts
Gi6/1 12257503849375 13071231106 3143614034 5432878057

Port OutOctets OutUcastPkts OutMcastPkts OutBcastPkts
Gi6/1 11717066321070 18408685487 609356341 18673458

It is connected to a Catalyst 3650. According to the show interface command, both negotiated to 1000/Full.

Neither is hard coded in the config.

Router#sh int g6/1
GigabitEthernet6/1 is up, line protocol is up (connected)
 Hardware is C6k 1000Mb 802.3, address is ccef.4838.97d5 (bia ccef.4838.97d5)
 Description: Link - Switch
 MTU 1500 bytes, BW 1000000 Kbit, 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 10/100/1000BaseT
 input flow-control is off, output flow-control is off
 Clock mode is auto
 ARP type: ARPA, ARP Timeout 04:00:00
 Last input never, output never, output hang never
 Last clearing of "show interface" counters never
 Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
 Queueing strategy: fifo
 Output queue: 0/40 (size/max)
 5 minute input rate 5322000 bits/sec, 840 packets/sec
 5 minute output rate 5482000 bits/sec, 1109 packets/sec
 21648165990 packets input, 12257873125877 bytes, 0 no buffer
 Received 8576527094 broadcasts (3143618679 multicasts)
 0 runts, 0 giants, 0 throttles
 5907 input errors, 1 CRC, 1 frame, 0 overrun, 0 ignored
 0 watchdog, 0 multicast, 0 pause input
 0 input packets with dribble condition detected
 19037327397 packets output, 11717449013650 bytes, 0 underruns
 0 output errors, 0 collisions, 5 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


Switch#sh int g2/0/48
GigabitEthernet2/0/48 is up, line protocol is up (connected)
 Hardware is Gigabit Ethernet, address is 00a6.ca7e.5d30 (bia 00a6.ca7e.5d30)
 Description: Link - Router
 MTU 9000 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 00:00:01, output never, output hang never
 Last clearing of "show interface" counters never
 Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
 Queueing strategy: fifo
 Output queue: 0/40 (size/max)
 5 minute input rate 4609000 bits/sec, 942 packets/sec
 5 minute output rate 4489000 bits/sec, 735 packets/sec
 501149223 packets input, 310028365436 bytes, 0 no buffer
 Received 7212540 broadcasts (6870769 multicasts)
 0 runts, 0 giants, 0 throttles
 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
 0 watchdog, 6870769 multicast, 0 pause input
 0 input packets with dribble condition detected
 436320462 packets output, 306635272326 bytes, 0 underruns
 0 output errors, 0 collisions, 1 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

Georg Pauwen · ‎01-10-2019

Hello,

it could be simply related to a bad cable as well, can you try and replace that ?