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WAP581 link flapping


Wrestling with these WAPs for almost a year now and the hopeful resolution, I believe, is contained in this thread—meaning wait for a firmware patch that's allegedly under active development.

Countless other threads on 581s flapping, 'losing wireless,' randomly and periodically disconnecting, sometimes resolves itself, sometimes not. I've pored over auto-MDI/MDIX (apparently negotiated at random), PoE (not it), LLDP/LLDP-MED (certain TLVs may or may not be problematic), spanning tree (disabled since not using bridge/WDS), ARP (timeout settings). The cluster daemon has also been mentioned elsewhere as a potential culprit.

Now wondering if the SNTP implementation has anything to do with it. The SNTP event "Unable to resolve host name" is an apparent false positive, because the DNS name is always resolved near-simultaneously.

Two-device cluster, and pictured below are logs showing the dominant AP flapping over a period of hours. This stopped only after logging into the switch, and then attempting to resolve the DNS A record for the cluster management IP . . . ? No other steps taken toward resolution, i.e. it 'fixed' itself:

NTP settings.png

Issues start at ~02:45:

WAP log.png

core log.png


Any employees with an update on the firmware update or otherwise?

2 Replies 2


Twenty-four hours later—all is stable, no flapping. Will be periodically updating this thread, maybe in another 48 hours.

Chet Prokop

We've seen a very similar scenario with several multi-AP setups with 581 ... latest fw. Also 350-series "ample" powered PoE+ switch. Latest location has 6 APs and have to put the last two on PoE+ injectors as the 350 switch shows dropping link on one then the other and restarts those APs. Also randomly get "unable to get an IP" from the 340 router.

Seen the same sort of issue at 3 locations and gone through each repeatedly with no sustained, consistent solution. 

Chet Prokop, PE, PhD
Cisco Select Partner
SMB - IT and Telecom Services
Houston, TX
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