Input Errors on Interface (Cisco 4507)

[mchappell]

I have a Cisco 4507 and just implemented Zabbix to monitor our infrastructure (replacing Nagios).  I am now starting to see a lot more information about potential issues than I did with Nagios which is a double-edged sword.

The biggest issue I'm seeing at the moment is that I am getting a large number of input errors on our primary FIOS line.

Here is the output for that interface.

sh int gi5/11
GigabitEthernet5/11 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet Port, address is 0013.6047.3b42 (bia 0013.6047.3b42)
Description: FIOS X1 IN
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 11/255, rxload 47/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, link type is auto, media type is 10/100/1000-TX
input flow-control is on, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters 00:04:55
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 21
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 185020000 bits/sec, 23507 packets/sec
5 minute output rate 44378000 bits/sec, 13048 packets/sec
6550231 packets input, 6308927668 bytes, 0 no buffer
Received 260 broadcasts (0 multicasts)
0 runts, 0 giants, 0 throttles
5875 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
3703876 packets output, 1628307334 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 output buffer failures, 0 output buffers swapped out

I am unclear as to what might be the issue, so any clues are appreciated.  This isn't a critical issue because this switch is set to be sunset and decommissioned by the end of the year, but I would like to know what's going on as it might explain some bandwidth issues we've been having with this FIOS line.

Thanks!

[M02@rt37]

Hello @mchappell 

Few things to check:

Check the duplex settings on both ends of the link (switch and FIOS device). Ensure they match (both set to full-duplex, for example).

Verify that the speed settings on both ends of the link match (both set to 1000Mb/s in this case).

Do you check if other interfaces on the same switch or on the FIOS side are experiencing similar issues. This can help identify whether the problem is specific to this link or more widespread.

[Richard Pidcock]

How fast are these input errors building?  When is the last time you cleared counters on the interface?  I would recommend clearing counters on the interface and continuing to watch it; maybe it's not as much of a problem as you might think. As suggested, by M02@rt37 also check for speed/duplex mismatches.  I would say consider a patch cable replacement but I don't see any CRC errors which would usually present if it was a cable issue.

[mchappell]

I cleared the counters about 5 minutes before the output I posted.  

The duplex setting on the switch side is Full, but I do not have access into the Verizon device to check that, same goes for the speed.  I am not seeing these errors on other ports.

Like I said, this may ultimately be a non-issue since this switch is getting decommed in a few weeks.  If I see the issues on the new switch, then I might start killing more brain cells on it.

Thank you for the input!

[MHM Cisco World]

Show interface counter errors 

Let see which one is input error.

[Richard Pidcock · Accepted solution]

I suppose you could consider setting your side to auto negotiate just to see if it makes things any better, but if this is not causing any notable performance issues and it's getting decommissioned soon it may not be worth worrying about.