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7925G Scan Mode help - Plus bad roaming

matthew-f
Level 1
Level 1

Hey All:

Im having an issue with some 7925G, the A / 5Ghz inside works like a dream, when we go outside the phones start going crazy, we have 1310G's outside using 2.4GHz, the phones just wont roam. If you stand 30 metres from the external AP towards the car park, the IP phones still prefer the A wireless inside even though the signal is -90. Phone mode is auto-a, but havign tweaked the roaming settings i would expect the phnes to use the G signal

currently i have the scan mode set to auto, i cant find the menu option to select continuous. Within the WLAN profile there just isnt an option to select the scan mode. Any ideas? I want to test continuous scan mode before drilling in too deep

If anyone has any positive thoughts they could add, i would rather grateful, VERY grateful for some help

Thanks

Matt

9 Replies 9

migilles
Cisco Employee
Cisco Employee

Ensure you are using firmware 1.4(3) or later.

Also need to ensure that the 2.4 GHz CU is below 105.

You may want to enable continuous scan mode.

There is a small hit on idle battery life, but will still last for days.

You configure the continuous scan mode in the Cisco Unified Communications Manager in the product specific config section.

See my 7925G Deployment Guide for more info.

http://www.cisco.com/en/US/docs/voice_ip_comm/cuipph/7925g/7_0/english/deployment/guide/7925dply.pdf

If you do the above, then should be good to go unless you are hitting environmental, RF, AP or other issues.

I appreciate the quick reply.We are running callmanger express not callmanager.  Can you advise how we enable the scan mode for express?

We have the latest firmware

Could you advise on the CU? Using the site survey it shows below 70

Matt

I really need if possible a quick overview on how to enable the different scan mode in CUCME

The info for CME is also in my guide.

Look in the Product Specific Configuration Options section.

To enable continuous scan mode, create an ephone template with the following set.

     service phone scanningMode 2

Scan Mode

scanningMode

0 = Auto; 1 = Single AP; 2 = Continuous

You have come to party BIGTIME. I'll try it in the morning and then mark as correct

Matt

Thanks for the pointer Migilles.  I was able to set the scanningMode field to Continuous under telephony-service as opposed to the ephone template in CME

rsalahuddin
Level 1
Level 1

Where do I go on CUCM to check or change settings for Continuous Scan Mode?!?

Thanks in advance!

-Rez

Below is what I provided previously.

You configure the continuous scan mode in the Cisco Unified Communications Manager in the product specific config section.

See my 7925G Deployment Guide for more info.

http://www.cisco.com/en/US/docs/voice_ip_comm/cuipph/7925g/7_0/english/deployment/guide/7925dply.pdf

migilles
Cisco Employee
Cisco Employee

To revisit Matthew's original issue, it is possible that you were encountering the following caveat assuming you are using firwmare 1.4(2), 1.4(3), or 1.4(3)SR1, which is scheduled to be resolved in the 1.4(4) release due out in Feb 2013.

CSCtz46981     792x on 2.4 GHz utilizes QBSS for roaming decisions

This would only be an issue if the CU for the target AP's channels is >= 105.

You could try to increase the QBSS threshold via the WLAN controller UI to a higher value than 105 (I.e. 150) assuming the 792x phone is not roaming due to high QBSS (>=105). The scale is 0-255.

But is best to work to get the CU below 105 by either changing data rates, tx power or channels as even if the threshold is increased there could still be poor audio quality when associated to a busy channel.

config advanced 802.11b 7920VSIEConfig call-admission-limit

CAC (TSPEC) can also come into play if enabled and on call when attempting to roam to an AP utilizing a busy channel, where the 792x phone would try to roam to another neighbor or drop the call if no neighbor is avaialble.

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