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All of my 3702e generate input errors on switchports

Christian S.
Level 1
Level 1

Hello everybody,

I started replacing our 1262n with new 3702e and found a curious problem. All switchports on different switches where the new 3702 are connected have input errors. These error counters get incremented by 1 every 30 seconds, even if there are no clients connected to the AP on this port. These ports and the cabling are ok, I can change back to a 1262 and get no more input errors, but really all of the 3702 generate 1 error every 30 seconds.

So, what's wrong with them? What about others with these APs, are your interfaces free of errors or do you experience the same problem?

I have no special config on my ports, they are just simple access ports with the capwap-vlan applied, all APs are in local mode:

Current configuration : 141 bytes

!

interface FastEthernet2/2

description apxxx

switchport access vlan xxx

switchport mode access

spanning-tree portfast

end

If others experience the same issue then there's something wrong with the code but if I'm the only one I'd take the time to do further investigations.

Thank you and kind regards,

Christian

22 Replies 22

Hi Christian, I have this very exact problem too. I have many 3702i APs. 

What we have fount is the same. Every 30 seconds we get a input error.

We have seen that this only happens on APs with power injector installed 

and not when they connect to 2960x with poe+ support. So it seems to be the switchtype

doesn´t matter. Have you found anything new or solved this issue ?

No Kristjan, as already said in my last response I stopped doing further investigations since everything runs fine and obviously it's only a cosmetic thing on these old 4k5 chassis. The captures didn't show any anomalies.

 

Regards,

Christian

 

After upgrading to 7.6 MR2 (7.6.120.0) these errors are gone, Cisco finally fixed the code.

 

Regards,

Christian

 

Bug identified:

https://tools.cisco.com/bugsearch/bug/CSCun12965

Symptom:
Lightweight AP may send CAPWAP packets whose size is larger than 1500 bytes for testing maximum Path MTU.
These large CAPWAP packets cause giant errors on a directly connected switch, if the switch does not enable jumbo frame support.
Because AireOS based Wireless LAN Controller does not support jumbo frame, this behavior should not be enabled by default.

We had already spotted this bug and updated our WLC´s

We no longer have problems with giant frames.

 

-Helgi

May not be related but look at this thread.

 

It looks like the interface where the AP is directly connected to a 3850 needs the command "<ap name> no jumbo-mtu".

Hello everyone,

I have this problem but I have noticed that the errors are giant packet errors.

So on a WS-C2960X-48LPD-L with poe+ I have no input errors but every 30 seconds I get a giant packet.

running: Version 15.0(2)EX3

sta-s28-3c-sw3#sh int g1/0/7
GigabitEthernet1/0/7 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 5ca4.8a01.9e87 (bia 5ca4.8a01.9e87)
  Description: WiFi_S28_AP_VLAN
  MTU 1500 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 00:00:13, output 00:00:01, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 2000 bits/sec, 1 packets/sec
  5 minute output rate 1000 bits/sec, 1 packets/sec
     4557537 packets input, 1434379750 bytes, 0 no buffer
     Received 362717 broadcasts (220768 multicasts)
     0 runts, 141288 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 220768 multicast, 0 pause input
     0 input packets with dribble condition detected
     9364634 packets output, 1015555806 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     14716 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

 

on a WS-C2950G-48-EI and a AIR-PWRINJ4 get an input error every 30 seconds and the number of giant packets match exactly.

running: 12.1(22)EA14

FastEthernet0/24 is up, line protocol is up (connected)
  Hardware is Fast Ethernet, address is 0013.1aad.d498 (bia 0013.1aad.d498)
  Description: WiFi_A25_AP_VLAN
  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 100BaseTX
  input flow-control is unsupported output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:02, output 00:00:01, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 3000 bits/sec, 2 packets/sec
  5 minute output rate 1000 bits/sec, 2 packets/sec
     31221306 packets input, 139951215 bytes, 0 no buffer
     Received 1951648 broadcasts (1583274 multicast)
     0 runts, 40301 giants, 0 throttles
     40301 input errors, 1 CRC, 2 frame, 0 overrun, 0 ignored
     0 watchdog, 1583274 multicast, 15 pause input
     0 input packets with dribble condition detected
     573825515 packets output, 2838513941 bytes, 0 underruns
     0 output errors, 0 collisions, 4 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

Looks to me that it has nothing to do with the power injectors or switches, the packets christian.schrank was describing seem to be the cause of the problem...

Since I do not have a 3850 I cant use the "no jumbo-mtu" command for AP's...

 

Any ideas?

Seems to be leaning towards a TAC case though...

binhkdinh
Level 1
Level 1

I had the same issues and found this link below.

https://supportforums.cisco.com/discussion/12102821/3602i-aps-w-80211ac-module-input-and-crc-errors-connected-3850-switches

C3850#ap name AP-NAME no jumbo-mtu

 

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