Problems with Ascom after LWAP

Unanswered Question
Jul 3rd, 2010

We have an area where we have folks using Ascom phones which the reports we are getting are that the phones worked much better before they were lightweighted.  We have the controller setup per Ascom's recommendation and have worked extensively with Ascom but have yet to be able to get these phones stable.  Before the upgrage they had a very dense environment and the APs were all cranked to full power.  Looking back through the configurations before the upgrade there were some of the APs that did not have the Ascom WLAN on them so we went through created an AP group without Ascom on it to make it so that essentially the same APs had the Ascom WLAN on them but still had the same issues.

I understand the concept that the Lwapped APs are doing a tunneled connection back to the controller and the path is pretty simple as the path goes:

AP===>3560=====>6513=====>6509=====>6513 VSS Pair where the WISMs are installed and the Ascom voice gateway is on that same VSS Pair as the Wisms.

Anyone ever involved with these phones in a lightweight environment that might be able to give some pointers?

Thanks

Mike

I have this problem too.
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George Stefanick Sun, 07/04/2010 - 20:43

Hi,

I have pretty extensive experience with Ascom i75's and Cisco WLCs. Deployed over 20+ solutions. A few questions:

Have you had a proper voice survey?

Is QoS properly deployed on the wireless and wired side?

Is there particular areas that are issues or is it everywhere?

What exactly is the issue; jitter, disconnects ??

What firmware is deployed on your phones?

What security are you using on your voice WLAN?

mwkirk Sun, 07/04/2010 - 21:21

George,

Thanks for the response......

We have gone through the the Airmagnet survey tool after the fact and we've put together where we would like th AP placements to be and such but we have been working with the original AP placements.  Again, the perception here is that everything worked fine before we migrated them to a Lightweight environment.

QOS should be good.  We have worked with Ascom support quite a bit on this and using the debug tool on the phone we can see that the DSCP values are being set on the send and receive.

There are areas where it seems worse but then there are times when we have users who say it is bad everywhere.

There are times when we have disconnects but the issue more often than not is the voices are garbled or it sounds "tinny" or like there is a mechanical sound in the background.

We are using I75 and I75 Messengers and the majority of the phones are at 1.6.16

Using WEP for security

Ascom has consistently told us to use the RRM features of the WLC with a power threshold of -70 and our experiences have been that at that level it powers the radios down way too low.  Ascom has told us the "sweet spot" for their phones is at an RSSI value of -65 but we've found when the RSSI gets much below about a -55 the rate of the garbled calls goes up.

We have everything setup exactly as Ascom has advised and even had someone onsite from Ascom but did not get any further on making things better and actually made them worse by the time he departed.

cnowak1974 Fri, 07/09/2010 - 05:30

I've had a lot of experience in this area as well. I have good news and bad news. Good news you can get Ascom to work on LWAP, bad news it can take a lot of time and require the movement of quite a lot of APs to get the coverage just right for Ascom.

A couple of other questions:

How many SSIDs are you broadcasting?

What is the typical overlap between cell coverage?

Have you reviewed the logs on the phones? If you access the phone via a web page you can see it's roaming charateristics

Your issues sound like QOS to me.

How many controllers do you have set up?

Is roaming different when roaming from AP to AP on the same controller, or roaming between controllers?

What version are your controllers at?

Unfortunately Ascom is NOT Cisco, setting up Cisco gear to work appropriately for Ascom is best accomplished by work with folks who have accomplished this task. (George, #54, Bob Sayle, #54).

What area of the country are you located in? I can see about getting some Cisco folks I've worked with to help you out.

I'll be checking this often, looking forward to helping you

Charlie Nowak

mwkirk Fri, 07/09/2010 - 19:10

1.  SSIDs broadcasting....There are 8 SSIDs on the controller

2.  There is a lot of overlap....That is one of the main things we have been trying to mitigate.

3.  Yes we have looked at the phone logs.  Specifically what info are you looking for there?

4.  There are a total of 3 WISMs so 6 controllers total.  In this particular area I have had the APs on just one controller so I could tweak it without adversly affecting other areas.

5.  Same controller

6.  6.0.196.0

I am in the Atlanta, Georgia area.  Unfortunately, this customer had taken about as much pain as they could handle with this issue so we converted the APs back to autonoumous.  At this point they are stable with some issues that we can probably fix by adjusting power levels on APs.

I know co-channel interference is a big deal but I guess I am grasping at straws to understand why when the APs are autonoumous and we have all the APs at full power everywhere things actually work pretty well.  However, when we lwapped them it went down the tubes.  We had the lwapped environment to the point where it was working pretty well with the exception of during some hours when were thinking that the phones were being used the most.  Getting it there was a matter of adjusting power levels, testing, adjust, test...etc. etc.

We need to develop a plan to go back to lwapp as that is where we need to be.  That may include doing an overhaul of the whole thing and replacing APs and such since the ones in place are getting rather old (1231s).

Thanks

Mike

Kayle Miller Fri, 07/09/2010 - 07:00

mwkirk,

     I had an installation about a year and a half ago that was a nightmare and I spent over 72 hours straight with Cisco and Ascom working thru the issue in total we probably had 20 engineers working on it when you combined all of the vendors. We found an odd issue that was causing intermittent behavior on this particular system. Maybe the info below might help.

     What code revision are you running?

     How many SSID's are you broadcasting?

     What type of AP's?

     Lastly do you have Aironet IE Extensions and WMM Required on the Ascom SSID?

     The scenario we experiened we were running the newest version of 4.2 code with WiSM's and cisco 1242 AP's, and tried several versions for 5 and other versions of 4 with the same issue. We had 8 SSID's and were running Aironet IE extentions and WMM as Required.  once we set WMM to allowed and turned off IE Extensions the ascoms worked fine in this install.

See if any of this helps.

Thanks.

mwkirk Fri, 07/09/2010 - 19:15

Kayle,

Thanks for the response....

1.  Code...running 6.0196.0

2.  8 SSIDs

3.  Older 1231s

4.  Yes to Both

The WMM and IE extensions would be something interesting to try as I know I have reviewed the configuration over and over with Ascom.  If you read my reply to Charlie above you will see we ended up dropping back to autonoumous.  But, I need to come up with a plan to get them back to Lightweight  which may include an overhaul of the whole area with new APs and such.

Thanks

Mike

cnowak1974 Fri, 07/09/2010 - 20:09

Mike,

I'd definitely take the advice about the WMM settings. The problems you were describing do not sound like roaming issues which you'd normally expect from a dense AP deployment and co-channel. If you type *#46# on the phone does it show the WMM is on?

I've experienced issues on older versions of the WLCs that the WMM would not be valued in the wireless trace.

The logs on the Ascom phone should show DSCP being intact to and from the phone.

I'd have to dig through some emails, or setup my Ascom system here at home to get the exact log file information.

If the customer is locate din Atlanta, is it CHOA, or Gwinnett?

Unfortunately, it is a rare occasion for Ascom and LWAP to work nicely together on the first, second, third......

Do you have U-APSD enabled? I think Cisco made combined that setting with WMM on the newer release for the WLC. make sure U-APSD is OFF on the Ascom phones.

mwkirk Fri, 07/09/2010 - 20:16

Ok...I will have to check into the WMM.  Again, that is something I definitely remember Ascom telling me to have on.

The DSCP values are intact.  When you look at the phone logs you can see the 0x2e value up and down.  I've had issues with that before so I've seen that.

This is Gwinnett and I will have to check on the U-APSD.  I will also check the *#46#.

Thanks Again

Mike

cnowak1974 Fri, 07/09/2010 - 20:19

I figured it was Gwinnett. I've heard through the grapevine they were having issues.  Tell Ray I said Hi.

Let me know how things work out. George and I put a lot of work into getting that trial working nicely. They were all fat APs when were out there. Those APs they had were older than dirt and half of then had never been used from reading through the logs.

mwkirk Fri, 07/09/2010 - 20:32

Yup.... When you were throwing company names out I just looked you up on Linked-In and then it hit me who you were.  Yeah the APs are really old and that may be part of getting everything in order as they need to be replaced anyway.  We have 1252s installed in the new tower that are lightweighted and we have those working pretty well with Ascom.  Based on some of the suggestions here I am thinking we might be able to get them working even better.

Some of the suggestions are very contrary to what Ascom has told us.  Which that doesn't necessarily surprise me.

Thanks Again

Mike

George Stefanick Sat, 07/10/2010 - 20:19

LOL... SMALL WORLD!

Tell Ray i said HI as well..

Yea, if you want we can all get on a call perhaps sometime this or next week..

Who ended up landing your LWAPP install?

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