CDP shows two devices after changing name of AP

[sai teja]

I have changed the access point name in controller and it shows two access point names  , the one i have changed  and  the previous existing one. what  behavior is this ?

before  changing : 

SW01#sh cdp nei
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
D - Remote, C - CVTA, M - Two-port Mac Relay

Device ID Local Intrfce Holdtme Capability Platform Port ID
ap02.xxx  Gig 1/0/19 177 R T AIR-AP380 Gig 0

After  changing  : 

SW01#sh cdp nei
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
D - Remote, C - CVTA, M - Two-port Mac Relay

Device ID Local Intrfce Holdtme Capability Platform Port ID
ap01.xxx  Gig 1/0/19 175 R T AIR-AP380 Gig 0
ap02.xxx  Gig 1/0/19 56 R T AIR-AP380 Gig 0

[Richard Burts · Accepted solution]

CDP has been running and had a record of seeing device named ap02.xxx on its interface and keeps that information for a while. Then CDP learned a new ID and created a new record for the neighbor. So for a while CDP reports both neighbors. After a bit the older record times out and is removed. At that point you will see a single neighbor (as you expect).

[sai teja]

yes @Richard Burts  , just  after 5 minutes , i have  checked and now  i am not seeing the old  entry. Now  everything looks good.

Thanks @Joseph W. Doherty @Martin L @Richard Burts  , You guys are really helpful to young engineers like me..........its a pleasure to be a part of this cisco community.

[Richard Burts]

You are welcome. I am glad that our explanations have been helpful. When I was a beginning network engineer I found a similar community in which I learned a lot and was grateful for those who shared their knowledge with us. Now I (and my colleagues) are glad to share what we have learned with you.  Thank you for marking this question as solved. This will help other participants in the community to identify discussions which have helpful information. This community is an excellent place to ask questions and to learn about networking. I hope to see you continue to be active in the community.

[Martin L]

it is normal CDP behavior; older entries will time out in "default timer" which I think is 3 minutes and only valid entries will stay.

I guess you could change timer of CDP but nobody does it since it is not that big of a deal.

you could try clear cdp neighbors to see of that helps.

Regards, ML
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[Joseph W. Doherty]

As Rick and Martin have already noted, it's normal behavior.

I too was a bit surprised when I first saw this behavior, as I didn't realize that CDP caches its information for a short while.

I suspect the reason CDP does this, is to avoid some form of "flapping" CDP device information if CDP misses a few announcements.