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New Member

ports on 2950 keep dropping

Maybe you can make some sense of this. 1st floor computers appear as though their network connections drop. Not all at the same time though. There are still link lights though. we assumed network was gone because they couldn't work with the servers anymore and couldn't ping their gateway on the corerouter. I had run a netdiag /debug and we saw it find everything up to the gateway then it stalled. We then tried pinging the router and the gateway, no response but we then pinged servers up here an got responses. Just to check, we tried the gateway again and got no response. Reset the network connection and it all comes back.

A trace at the time showed no response from the first hop then a response from the server.

the switch os info:

Cisco Internetwork Operating System Software

IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(11)EA1, RELEASE SOFTWARE


Copyright (c) 1986-2002 by cisco Systems, Inc.

Compiled Wed 28-Aug-02 10:25 by antonino

Image text-base: 0x80010000, data-base: 0x80528000

We do have port fast on and tried to configure the ports for both auto and static speeds with the workstation configs to be matched.

New Member

Re: ports on 2950 keep dropping

Maybe you should check errdisable config first, and, also use "full duplex" mode to fix the collision on the interface.

Below I am giving the steps on how to recover from error disable state on 2950 for your reference.

errdisable recovery

Use the errdisable recovery global configuration command to configure the recover mechanism variables. Use the no form of this command to return to the default setting.

errdisable recovery {cause {all | bpduguard | dtp-flap | gbic-invalid | link-flap | pagp-flap |psecure-violation | udld} | {interval interval}

no errdisable recovery {cause {all | bpduguard | dtp-flap | gbic-invalid | link-flap | pagp-flap |psecure-violation | udld} | {interval interval}

Syntax Description

cause Enable error disable to recover from a specific cause.

all Enable the timer to recover from all error-disable causes.

bpduguard Enable the timer to recover from the bridge protocol data unit (BPDU)-guard error-disable state.

dtp-flap Enable the timer to recover from the Dynamic Trunking Protocol (DTP)-flap error-disable state.

gbic-invalid Enable the timer to recover from an invalid GBIC error disable state.

link-flap Enable the timer to recover from the link-flap error-disable state.

pagp-flap Enable the timer to recover from the Port Aggregation Protocol (PAgP)-flap error-disable


psecure-violation Enable the timer to recover from a port security violation disable state.

udld Enable the timer to recover from the UniDirectional Link Detection (UDLD) error-disable state.

interval interval Specify the time to recover from specified error-disable state. The range is 30 to 86400 seconds. The same interval is applied to all causes. The default interval is 300 seconds.

Note The errdisable recovery timer initializes at a random differential from the configured interval value. The difference between the actual timeout value and the configured value can be up to 15 percent of the configured interval.

Note Though visible in the command-line help string, the channel-misconfig keyword is not supported.


Recovery is disabled for all causes.

The default interval is 300 seconds.

Command Modes

Global configuration

Command History

Release Modification

12.1(6)EA2 This command was first introduced.

12.1(9)EA1 The gbic-invalid and psecure-violation keywords were added. The rootguard keyword was removed.

Usage Guidelines

A cause (bpduguard, dtp-flap, gbic-invalid, link-flap, pagp-flap, psecure-violation, and udld) is defined as the reason why the error-disabled state occurred. When a cause is detected on an interface, the interface is placed in error-disabled state, an operational state similar to link-down state. If you do not enable errdisable recovery for the cause, the interface stays in error-disabled state until you enter a shutdown and no shutdown interface configuration command. If you enable the recovery for a cause, the interface is brought out of the error-disabled state and allowed to retry the operation again when all the causes have timed out. Otherwise, you must enter the shutdown then no shutdown commands to manually recover an interface from the error-disabled state.


This example shows how to enable the recovery timer for the BPDU guard error-disable cause:

Switch(config)# errdisable recovery cause bpduguard

This example shows how to set the timer to 500 seconds:

Switch(config)# errdisable recovery interval 500

You can verify your settings by entering the show errdisable recovery privileged EXEC command.

Related Commands

Command Description

show errdisable recovery


Displays errdisable recovery timer information.

show interfaces <>

status Displays interface status.

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