May 28

Wireless Client cannot see the Access Point

I often get contacted regarding wireless clients not working in an area where there is a known access point. When I get into the controller, I never find a problem. The access point and the radio’s all show up. These clients are always using 802.11a, I have never had this problem using 802.11b/g, but it’s still possible to have this issue..

I often find that by changing the channel on the access point resolves the issue. This can be due to a couple different issues, but often has the same root cause.

On a Cisco Wireless LAN Controller (WLC) there are 21 channels that can be used. I have found that some clients do not support all 21 channels. When the WLC is allowed to use the default Dynamic Channel Allocation (DCA) settings, there is a good chance that there are channels allowed to be used that are not supported by the client. You can change these allowed channels under Wireless –> 802.11a/n –> DCA, then it’s under “DCA Channels”. You only want the supported channels listed in this field. If there is a channel in this field that is not supported by your client, it won’t work on the AP’s that use that channel.

I had a client that had set their Cisco 7921G wireless phones to only support channels 36, 44, 157, 165. A user noticed that the phone didn’t work in a couple of areas. After some digging, we found out that channel 161 was in the DCA list. Simply removing it and giving the system time to adjust resolved the problem.

Instead of checking for Co-Channel interference or replacing Access Points, check the channels first, it may be an easy fix for you.

Have you run into this before?
What client had the issue and what channels didn’t it support?

May 21

Mobile Connect — Do you use it? Do you like it?

Mobile Connect is a really nice feature in Cisco Unified Communications Manager (CUCM). When somebody calls your desk phone, it will also ring your cell phone. It doesn’t have to be a cell phone, it could even be a home phone. When I call somebody at the office from my cell phone, their caller ID on their desk phone displays my name and my desk phone’s number. I have tricked a few people thinking I was at my desk when I was in my truck driving to work.

When I am away from my desk, I can still receive important phone calls from people calling my desk phone. After answering the call on my cell phone, I can then walk back to my desk and transfer the call back to my desk phone. Even though I have them on my cell phone, I like the comfort of my desk’s headset, so I transfer them to my desk phone.

There have been times that I get on a conference call and it runs late, then it’s time to go home for the day. I can simply transfer the call to my cell phone and head home and nobody knows that I have left work for the day.

If you are not familiar with Mobile Connect, your probably thinking this is pretty cool and something you want to have. It is pretty cool and if you have CUCM you should implement it, management loves it! If you have another system, you should look into a similar feature on your system.

I have one and only one problem with Mobile Connect, Cold Calls. When a call comes to my phone, I get their caller ID. If it’s a known number, it will pull the name from my address book on my cell phone and the caller ID tell me who is calling me. If it’s not a known caller, it just gives me the number. Lately, I have been getting more and more Cold Calls from sales people that I don’t know and I don’t want to talk to. Most of the time I have no need for their product, but I get stuck talking to them because I don’t want to be rude. Over and over this has happened to me. So, I only enable Mobile Connect when I’m expecting an important phone call and need to step away for a bit.

Do you use Mobile Connect? Do you love it or hate it and why?