Solved: Wireless IP phones roaming problems (one way audio)

Georgios Nikitas · ‎03-27-2008

Hi,

i have a site with 8 1240AG APs and several 7920s and 7921s.

APs are running 12.3(8)JEA.

Sometimes I have one way audio between the IPPhones. After debugging i found out the following:

Sometimes (!)when a client is leaving an AP, AP-1 for example, and gets associated with AP-2, AP-2 sends the IAPP Sent Disassociation Notice to the other APs;

AP-1 receives the IAPP: Rcvd Disassociation Notice but does not disassosiates the client!

So, 7920 is on AP-2 but AP-1 thinks it is on itself, therefore does not send the IP packets to the new AP and we have one-way audio!

What could be going wrong?

APs are connected on a 2960 Cisco switch without vlan configuration.

The same problems exists at another site with similar configuration (1242 & 7920).

Thanks

migilles · ‎04-02-2008

Was a bug w/ IAPP fixed in 12.3(8)JEA2.

Also recommend to use 3.02 for 7920 and 1.1(1) for the 7921.

View solution in original post

irisrios · ‎04-02-2008

It is recommended to enable Dynamic Transmit Power Control (DTPC) on the Access Point (AP) by using the Limit Client Power field in the user interface to ensure that APs and Clients are using the same transmit power. Also ensure that NAT or firewall is not blocking the RTP protocol used for voice communications.

migilles · ‎04-02-2008

Was a bug w/ IAPP fixed in 12.3(8)JEA2.

Also recommend to use 3.02 for 7920 and 1.1(1) for the 7921.

meggerman · ‎04-03-2008

Where do you set DTPC ? i assumeon the WLC but where is the limit client power field ?

also we experience this and it appears that the clients are not roaming exactly in the same way g.nikitas has mentioned.

we can move to 1.1.1 in the meantime can you tell me how to set the above.

many thanks

Megz

victorgarciaternero · ‎06-12-2008

I have the same issue. I have upgraded Aironet 1242 IOS (124-10b.JA3) and the 7921 firmware (1.1(1)), but I can't see any change. The call manager is 5.1.

Thanks

meggerman · ‎06-12-2008

hi,

check mobility groups are same over the controllers. check channel assignment is correct and there is a decent overlap but no co-channel interference.

cheers