Cisco Switch “errdisable” and Wireless Link implementation Issue
Problem: Wireless solutions can experience momentary loss of link due to precipitation bursts, birds, etc. that may last only a fraction of a second. Ordinarily, this is not a problem as any failed Ethernet frames caught in that moment are just retransmitted. A CRC error may or may not be registered in a management log.
Cisco switches have a feature, “errdisable”, which is intended to place a port into a disabled state in the event that port experiences a physical disruption.
The issue that arises with any wireless link is that there will be physical disruptions, although normally brief and transparent to user experience.
This is not a problem unless the port is thereby disabled by Cisco “errdisable”. In this case, the link will be downed due to disablement of the wireless equipment’s Cisco port by the switch’s “errdisable”.
To mitigate this potential issue, the following is strongly recommended on all Cisco switches:
Configure the Cisco device to not enter “error-disable state” as follows:
1.) # show errdisable detect (the ‘show’ command shows how errdisable is currently set.)
2.) (config)# no errdisable detect cause all (the ‘no’ command shuts off all forms of errdisable.)
3.) You may need to do a reset on the Cisco’s wireless device port both sides to obtain link
Alternatively, for link down following an “errdisable” you will need to reset the Cisco switch ports