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Community Member

Input Errors specific to RUNTs

Hi All,

I have a current issue with a 2851 connected to a 3560G that is experiencing input errors which are incrementing along with the runt counters.

Both sides of the link are configured for 100Full and are both operating at this setting.

The 2851 is shaping outbound at 40Mbps whereby the 3560G has no Policing or Shaping applied. Could this be the cause of my issue? Obviously I have not ruled out a layer1 issue, but just wanted to run this scenario by you.

Please see excerpt below:


Config's
========

2851
----
interface GigabitEthernet0/1
bandwidth 40000
ip address <...>
load-interval 30
tx-ring-limit 32
tx-queue-limit 32
duplex full
speed 100
traffic-shape rate 40000000 4000000 4000000 1000

3560G
-----
interface GigabitEthernet0/9
switchport access vlan <...>
load-interval 30
speed 100
duplex full
mls qos trust dscp

Physical Interface Stats
========================

2851
----
GigabitEthernet0/1 is up, line protocol is up
  Hardware is MV96340 Ethernet, address is 0013.7f75.2e49 (bia 0013.7f75.2e49)
   MTU 1500 bytes, BW 40000 Kbit, DLY 100 usec,
   reliability 251/255, txload 5/255, rxload 33/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 100Mb/s, media type is T
  output flow-control is XON, input flow-control is XON
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:02, output 00:00:00, output hang never
  Last clearing of "show interface" counters 1w0d
  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 5253000 bits/sec, 714 packets/sec
  30 second output rate 815000 bits/sec, 548 packets/sec
     90935945 packets input, 3047346796 bytes, 0 no buffer
     Received 34192 broadcasts, 923316 runts, 0 giants, 0 throttles
     2836325 input errors, 1913009 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 0 multicast, 0 pause input
     0 input packets with dribble condition detected
     87658883 packets output, 2060672531 bytes, 0 underruns

3560G
-----
GigabitEthernet0/9 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 0026.520c.9b09 (bia 0026.520c.9b09)
  MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
     reliability 255/255, txload 7/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 100Mb/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 00:00:17, output 00:00:00, output hang never
  Last clearing of "show interface" counters 4w1d
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/0 (size/max)
  30 second input rate 648000 bits/sec, 354 packets/sec
  30 second output rate 2858000 bits/sec, 459 packets/sec
     335091714 packets input, 143509513355 bytes, 0 no buffer
     Received 7269 broadcasts (7254 multicasts)
     0 runts, 0 giants, 0 throttles
     2 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 7254 multicast, 0 pause input
     0 input packets with dribble condition detected
     374635505 packets output, 228051807872 bytes, 0 underruns

5 REPLIES

Re: Input Errors specific to RUNTs

Hi,

Though physical layer issue cannot be ruled out, as there are CRC, input errors on the interface, but what i m interested in is lots or Runts coming in. Do you have header compression applied anywhere near the router or switch? Does this link carries any Voip traffic? Do you have any other device capable of doing header compression?

HTH

Hitesh Vinzoda

Pls rate useful posts.

Community Member

Re: Input Errors specific to RUNTs

Hi Hitesh,


No there is no header compression enabled on either device. There is no VoIP traffic traversing that segment.

Cheers

Bronze

Re: Input Errors specific to RUNTs

Hello,

I would suggest disabling both input and output flow-control on the router.

Hope this helps.

Re: Input Errors specific to RUNTs

Can you run the SPAN on Switch and find out what exactly is traversing that link with size less than 64 byte.

HTH

Hitesh Vinzoda

Community Member

Re: Input Errors specific to RUNTs

Hi All,

Unable to run a SPAN via the switch due to this being customer infrastructure.

NBAR results display 5 protocol types which are mostly used for management ie: snmp, ssh, icmp. However there are some incrementing "unknown" protocol type counters that are obviously unexplained.

sh ip traffic stats indicate incrementing encapsulation failed packets being dropped.

Nothing out of the ordinary from the debug of the router.

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