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Wireless LAN (Voice)

Samphos Ngak
Level 1
Level 1

With Shankar Ramanathan  

Saravanan Lakshmanan Shankar Ramanathan

Welcome to the Cisco Support Community Ask the Expert conversation. This is an opportunity to learn and ask questions about how to monitor, troubleshoot, and configure voice over WLAN on Cisco Unified Wireless Network and 792x/9971 phones with Cisco experts Saravanan Lakshmanan and Shankar Ramanathan.

Additionally, the experts will cover relevant issues such as one-way voice, two-way failure (no voice), “robotic” or choppy voice quality, network busy, and leaving service area.

Saravanan Lakshmanan is a customer support engineer at the Cisco Technical Assistance Center, specializing in wireless technologies and solving high-severity and critical wireless issues for Cisco customers and partners. He is an expert in debugging and troubleshooting Cisco Wireless LAN controllers; wireless LAN services; unified access points; wireless LAN security; autonomous access points (Aps); voice over Wi-Fi (VoWifi); authentication, authorization, and accounting (AAA); and radio frequency (RF) technologies. As a technical content engineer, he creates and edits documentation to enhance product serviceability. During more than 10 years of engineering experience, he has served as QA specialist for the Cisco Wireless business unit and before that as a senior software specialist in QA for Motorola’s wireless engineering infrastructure team. Saravanan is a frequent contributor to Cisco’s internal forums as well as the external Cisco Support Community. He holds a bachelor of engineering degree from Annamalai University in Chidambaram, India. 


Shankar Ramanathan is a customer support engineer at the Cisco Technical Center specializing in Cisco voice over wireless LAN (VoWLAN) technologies, including 792x and 9971 phones. Prior to joining Cisco in November 2011, he worked as a wireless network engineer at Elan Technologies, responsible for RF wireless network planning, simulation, propagation path analysis, and optimization of Wi-Fi 802.11 mesh and WiMax (802.16 d/e) networks for various system integration and automation projects. Shankar holds a master of science degree in electrical engineering specializing in communications and signal process from the State University of New York, Buffalo. He is CCNA certified (number 410004168640IMZF) and has four years of industry experience.


Remember to use the rating system to let Saravanan and Shankar know if you have received an adequate response.  

Because of the volume expected during this event, Saravanan and Shankar might not be able to answer each question. Remember that you can continue the conversation on the Wireless, sub-community forum shortly after the event. This event lasts through August 23, 2013. Visit this forum often to view responses to your questions and the questions of other Cisco Support Community members.

35 Replies 35

alex.roth
Level 1
Level 1

Hi,

One question regarding the AIR OS and VoiP over WLAN . We are using right now 5508 & 2504 Controllers.  I´m using the newest version 7.4.100.0 and also 7.2 on the controllers  ( minimum 7.2 is needed because we are using also 26XX AP ).

I´m still confused which version is the best to use together with VoIP over VLAN . Right now it´s not so easy to follow up  with Cisco which IOS we should use .  I see many different IOS versions with many dependencies as example 7.5 with a newer NCS ( 1.4 ) version. Can you recommend and IOS which we should prefer ?

Thanks

Alex

HI Alex,

From WLC perspective, it is recommended you be on 7.4.110.0 (7.4 MR1) which will also be marked assurewave.

For 792x phones, its recommeded to be on latest 1.4(5) code http://www.cisco.com/en/US/docs/voice_ip_comm/cuipph/7925g_7925gEX_7926/firmware/1_4_5/english/release_notes/P256_BK_WDE1D1EF_00_wireless-phone-release-notes-1_4_5_chapter_00.html#P256_RF_R72B630D_00

Yes that is deemed the current maintenance branch.

7.4.110.0 was included in the recent version of the 7925G Deployment Guide, which was posted the other day.

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

Other recommended versions are below.

Recommended = 7.0.240.0, 7.2.115.2, 7.3.112.0, 7.4.110.0, 7.5.102.0

So if you still have 4400/2100, you gotta stick with 7.0.240.0.

If you have 5500/2500, then recommend 7.4.110.0 as mentioned above.

A word of caution on 7.5.102.0 and the AC module.  We tried to deploy 7925G's on 7.5.102.0 with AC modules on our 3602I's.  However none of the 7925g's would seamlessly roam between the AP's with AC modules.  The phones would do a complete reauth at every roam and show leaving service area on the phones.  Disabling AC didn't fix the issue, but physically removing the AC modules did.  Rather than remove 58 AC modules we reverted to 7.4.110.0.  Now the only issue is Prime still see's the AC modules as being down and you can't just delete the AC module from the database.  .

Yes, this has been the topic for today.

Basically, the 802.11ac modules for the Cisco AP3600 do not support CCX, therefore they do not support CCKM.

And since both radios are used for 5 GHz currently, you have 1 set of BSSIDs with CCKM support 1 set of BSSIDs without CCKM support (i.e. overlayed WLANs).

So if the 792x phone connects to a CCKM enabled BSSID, then tries to roam to the 802.11ac radio on the AP3600, then the roam attempt will fail and the 792x phone must then do a full 802.1x handshake (aka not fast roaming).

This issue (tracked via CSCui67756) is currently being worked, but until we have a solution for this issue, it is not advised to deploy 802.11ac modules if currently using mobile endpoints like 792x or Cius or wired WLAN endpoints like 9971 or DX650 as these are all CCX endpoints that utilize CCKM for fast roaming; more so for the 792x and Cius as these devices typically roam more frequently, where 9971 and DX650 require the AC power connection so can only move as far as the cord allows.

The following article has been updated to include this info as well.

https://supportforums.cisco.com/docs/DOC-26863

CSCui67756

Great!  Can't find this.  Is this an internal bug ID?

So if you still have 4400/2100, you gotta stick with 7.0.240.0.

If you have 4400/WiSM-1, raise a TAC Case and ask them to publish the latest engineering fix for you.

Why are the non-AC clients trying to roam to the AC module? 

"The radio module uses the 802.11ac explicit beamforming standard and does not support Cisco

Client Link 2.0, Cisco Compatible Extensions (CCX), or Radio Resource Management (RRM).
However, the internal 802.11n radio does support those features delivers them to legacy and 802.11n
clients."

I can't believe Cisco didn't test this code, specifically made for AC, with wireless voice before releasing it to customers.

The 11ac radio is advertising the same SSID as the internal 11n radio and both are responding to probe requests from the 7925 phones, therefore it can potentially attempt to roam to the 11ac radio using CCKM infused previously.

There will be a fix to address this issue, which hopefully will be available shortly.
Monitor the caveat I listed for more info.

I am simply the messenger giving you additional info on this issue.

Sent from Cisco Technical Support iPad App

Thanks for the information, not trying to shoot the messenger.   

Unfortunately I'm not able to access the caveat either, but I assume they'll update the case when there's a fix. 

Hi Dustin,

I have submitted a feedback in this regard so that the bug details are reviewed and is customer facing on BTK soon.

Like mentioned above stick with 7.4MR1, since it is latest on 7.4 track with many bugs fixed that were discovered from previous 7.X releases. Also, past 7.4.x.x codes will be yanked from cco soon if assurewave certification passed on 7.4MR1. For stability use code 7.4MR1, for feature set use 7.5 not commenting about stability part since it is too early to conclude.

Hi,

Many thanks for the clarification. That means I ´ll go forward with 7.4.MR1 for  . The problem with 7.5  right now is our used NCS version. We are using NCS 1.3 which is not comptabile as I know with 7.5.

Thanks

Alex

Hi,

Thanks again for the update . I will continue use NCS 1.3  & 7.4 because I can´t upgrade later with NCS 1.4 & 7.5  direct to NCS 2.0  and have to wait for 2.1 .

Regards
Alex

CSCO12204350
Level 1
Level 1

Hi

i the WSC but , icannot find the map , how can be slove the issue ???

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