Definitive Best-Practice for VoWiFi PDF (cellular calls over WiFi)

[benjammin1001]

Can anyone point to a definitive guide for best practices to set up older 2500 series (and similar) for Voice-over-WiFi?

I've been having carrier problems lately - and I want to make sure I have all my i's dotted and t's crossed with my 2504 system as well as a few out in the wild.

Lately, my carrier has had problems and I want to make sure it's them and not something else I've missed on my system (as well as the others I have running)

I did find something for VoIP -- but not sure how much crossover relates to what the cell carriers provide.

Thanks,

 -Ben

[eglinsky2012]

A solid RF design with good secondary signal and proper RRM tuning is the first step, along with 802.11r/k/v on the SSID, especially if the devices will be moving during calls.

There was just a discussion about WiFi calling on a private listserv I'm subscribed to. The gist is that WiFi calling utilizes IPSEC connections to the cell carriers for voice connections, so you may have to check logs for a non-working device and ensure that that protocol is allowed through your firewall for your wireless subnets. Some firewalls (namely Palo Alto) create separate inbound/outbound sessions for IPSEC-ESP, so that protocol would have to be allowed inbound as well. You might choose to only allow carriers' IPs/subnets inbound, in which case you'll have to do some research on what those IPs/subnets are unless there's a comprehensive list out there.

[benjammin1001]

Thanks for the reply.

Yea - the firewall has no restrictions for the WiFi devices that should interfere with IPSEC/ESP other than NAT from an RFC1918 to public IP.

And I'm aware of the various RRM and 802.11r/k/v -- but haven't found anything really definitive as to what to tweak and when for the 802.11r/k/v -- assuming the defaults are good. (I've seen the recommendations for the RRM though... )

Cheers,

 -Ben

[Leo Laohoo]

Try a different cellular carrier.

[benjammin1001]

Uhh...  and what happens when it's more than one carrier?

Not really a helpful reply.

[Leo Laohoo]

The truth is carriers really do not want to troubleshoot anything unless there is widespread issue or a Congressional Hearing.  

Go to a mall (or some place with good WiFi) and try WiFi calling.  Use a different carrier to see if the issue is the carrier or the phone. 

[benjammin1001]

I already know > 1 carrier doesn't work at one location.

And there's another single AP (Araknis) set up as a cross-test that seems to work fine with the same carriers.

So I'd like to rule out the Cisco system.

[Rich R]

It's focused on Apple products but take a look at https://support.apple.com/en-vn/guide/deployment/dep271900868/web
There are links to Cisco guides at the end.

But 2504 is end of support so you should be thinking about newer technology.  While you're still using 2504 at least make sure you're on the last available code version 8.5.182.11 (link below).

[benjammin1001]

Thanks for the links, I'll take a look to see which ones I've already seen -- but sanity checks are good.

And yea - they're all updated.  I doubt the clients are going to move to the newer catalyst stuff any time soon. Always about the $$$.

Again - appreciate the info,

 -Ben