Question

wifi calling

  • 11 July 2019
  • 4 replies
  • 220 views

Userlevel 1
How well does calling over the wireless network work? Does it tons of bandwidth to make a call? Is there some special settings that I can change on the controller or APs to make calling over wifi better?
I have a c5210 controller with 3605/3610 APs. Does anyone have any advice or experience with calling over wifi?

4 replies

Userlevel 7
Hi Laura, I found your question intriguing and decided to look it up. I think you'll find this article to be insightful.
https://www.networkcomputing.com/networking/your-network-optimized-wifi-calling
Userlevel 5
Hi Laura,

I'd add my favourite articles of Devin Akin, they apply to wireless connectivity in general but naturally also have influence on WiFi Calling that might be a delicate kind of traffic:
http://divdyn.com/top-ten-tune-tips/
http://divdyn.com/wi-fi-throughput/
http://divdyn.com/moo-mimo/

Hope that helps,
Tomasz
Userlevel 5
How well does calling over the wireless network work?

Hello Laura, sorry for such a late reply to this thread (I haven't been around for a while). But I can answer your question with more questions!

In my experience, there is very little bandwidth used for VOiP of any kind. A high quality audio stream might run 64Kb. Which "ain't much". MORE important is the density of your coverage. That is, how many AP's you have, how many can be seen at one time by the device, and how strong the signal appears to be. This is vital for roaming to work as someone walks down a hallway during a conversation.

There are a ton of little factors that you can tweak to make WiFi calls work better. We recently did a proof of concept with Vocera on an Extreme Wireless network consisting of C5210 controllers, and 3825i AP's. The only issue we experienced was that broadcasts to all devices (e.g. "EVERYONE, MAY I HAVE YOUR ATTENTION PLEASE") were not perfectly synced, which Vocera said was an indication we needed to lower our DTIM value to 1 on the AP's.

If you are planning a new network, I strongly suggest using planning software like Ekahau. With that you can pull in a map of the area, tell it what AP's you are using, and then tell it that you intend to use voice on this network. If your network has already been built, you can still use tools like these to tell you how well voice will work. But then also check with the vendor of your wireless VoIP gear and see if they have recommendations on settings.
Userlevel 2
We allowed WiFi calling about a year ago and it's been working well. However, as Steve said, there are density considerations you must meet. Ekahau has a feature to view your wireless design called "secondary coverage" which allows you to look at a heat map in terms of the 2nd AP in place to see if you can "trapeze" seamlessly to a nearby AP as you move.
Since we designed around 802.11 wireless phones, WiFi calling wasn't much of an issue when we turned it on.
If you have just enough coverage, by itself, WiFi calling will most likely work but will be spotty. It sure beats no coverage though.
As far as congestion, I wouldn't worry too much about it. If there's a lot of noise however, it may be problematic.

IMO, allow it and share your experience.

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