Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Runts on Fe

Hi All,

I have Ayaya phones connected to 4507R Version 12.2(20)EW1 and on the Fe interfaces,im receiving too many Runts and Input & CRC errors.I really not sure why Runts are being generated.Im pasting the config.would appreciate any help in this regard..

interface FastEthernet3/1

switchport access vlan 40

switchport mode access

switchport voice vlan 30

service-policy output autoqos-voip-policy

speed 100

duplex full

qos trust device cisco-phone

qos trust cos

auto qos voip cisco-phone

tx-queue 3

priority high

shape percent 33

spanning-tree portfast

qos dbl

qos map dscp 24 25 26 27 28 29 30 31 to tx-queue 4

qos map dscp 32 33 34 35 36 37 38 39 to tx-queue 4

qos map cos 3 to dscp 26

qos map cos 5 to dscp 46


policy-map autoqos-voip-policy

class class-default



Re: Runts on Fe

Hi Sachin,

A perfect configuration and I hope you will agree with me that these runts and CRC are majorly due to physical layer or data link layer problem.

I remember Avaya phones work on auto sensing feature. Is it possible for you to change the fa3/1 speed and duplex to auto auto and clear the counters and monitor it again.



New Member

Re: Runts on Fe

Hi Ankur,

Even i felt that the possible cause cud be a mismatch with the speed and duplex settings.But when i change it to auto the switchport goes to 10/half which is what i dont like and you will also agree.Im not sure if Avaya phones can be manually set to speed/duplex settings like Cisco IP.



Re: Runts on Fe

Hi Sachin,

That makes us clear with the reason for runts and crc and input errors. You Avaya phones are working on 10 half and switch is running on 100 full which is a mismatch and runts and crc are incrementing.

Can you please post the model number of your Avaya ip phone.



New Member

Re: Runts on Fe

The Avaya model is 4612.Can they be made to work at 100/full ???


Re: Runts on Fe

those things are OLD!!! and are only 10mb half duplex phones!!! only way to get them to 100Full you need to buy a avaya 30A data switch base for those phones

like this :

or get newer (not really new they been out for 2+ years) ip phones (4610/20/21/25)


Re: Runts on Fe

First what avaya ip phones are you running ?

If your running 4602/4610/20/21/25 first ensure you are running latest avaya firmware. 2.2.3 I think is latest. Second avaya ip phones work very well set to auto, but can be physically hardest via options button on phone or adding PHY1STAT 5 command to tftp script file.

Secondly, if you have 4606/12/24 avaya ip phones..get the above models.

Thirdly, rule out the 4700 blade, get another switch to see if the phones have the same issue.

CreatePlease login to create content