7921 disconnecting

[lzakariya]

Hi....

My 7921 cisco phone are disconnecting when going from one access point to another access point...what can be reason for this. Should I create a sepearte vlan for voice and data.

[Rasika Nayanajith]

This may be due to you do not have sufficient overlapping coverage to support the smooth roaming. It is recommended to have 20% overlap with at least -67dBm cell radius for VoWLAN.

Cannot say what the exact cause for client disconnection with given info & I would suggest to refer below design document to go through & see whether your wireless setup is comply to that

http://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/emob73dg/ch9_Voic.html

HTH

Rasika

*** Pls rate all useful responses ****

[lzakariya]

But it doesn not happen with other devices, only with cisco wireless phone 7921

[Rasika Nayanajith]

What do you mean by other devices ? Do you have any other phone models & are they working fine ?

What software version running on these 7921 ?  Also what is the WLC software code you running ?

Rasika

[lzakariya]

Other devices means laptops, mobiles etc,

My software version is 4.0.155.5 and I am using wlc 4402.

[Rasika Nayanajith]

It looks to me you are having too old (un-supported) software codes. I would  suggest to upgrade WLC to at least 7.0.116.0. Also look at the 7921 firmware running & upgrade it to latest code supported.

Still I believe your network does not have spec to support VoWALN, and that's reason for dropping client when roaming from AP to AP. Have you done any site survey to verify this ? The other devices may running either mostly in stationary or no voice services deploy on mobile phones other than 7921.

Do you have more than one controller & if so have you configured mobility among them ?

HTH

Rasika

**** Pls rate all useful responses ****

[abwahid]

Hi,

As per your description, yes It seems the coverage issue or interference issue, you need to make sure your wireless channel selection on your Access-points are low noise channels.

And it's good if you create separate VLAN for voice and data, but i think it wouldn't effect on your issue 

.