RE: Wi-Fi Calling in a corporate environment

[<chuckchurch () gmail com>]

Thanks all.  Oddly enough, it seems that the entire site’s userbase suddenly started working.  From what I understand 
no action was taken to fix anything.  So unless a dynamic PaloAlto update broke it and then unbroke it later, I’m not 
sure what was going on.  I’ll debug a bit to know what a working baseline looks like, since I’m not sure.

 

Thanks again,  

 

Chuck

 

From: Tom Beecher <beecher () beecher cc> 
Sent: Friday, August 2, 2024 2:03 PM
To: chuckchurch () gmail com
Cc: nanog () nanog org
Subject: Re: Wi-Fi Calling in a corporate environment

 

My understanding has been that generally, if the cellular network signal was above a certain threshold, phones won't 
even attempt to use wifi calling. Some carriers used to let you flip a switch to force the phone to prefer wifi over 
cellular, but some have removed that. ( Verizon for example. )

 

In my experience some years ago in a similar environment, that cellular threshold to switch was set so low that it was 
useless. I could be standing in a spot with barely tickling the bottom bar, and nothing. If I flipped to airplane mode, 
was able to wifi call instantly. 

 

On Fri, Aug 2, 2024 at 11:11 AM <chuckchurch () gmail com <mailto:chuckchurch () gmail com> > wrote:

Hey all,

 

               Question if anyone knows about cell phone wi-fi calling in US.  Googling isn’t finding what I’m looking 
for.  We have a corporate site in US where users have BYOD capability, and use their phones with wi-fi calling enabled. 
 Site uses a single NAT address (IPv4) for BYOD access.  Recently the site reported wi-fi calling had stopped working 
for all user phones, Apple and Android, all about the same time.  The guest network did have some bandwidth limitation 
applied and they had overuse.  That was since resolved, we upped the bandwidth.  But the phones all still avoided wi-fi 
calling.  It’s a manufacturing site with known cell signal issues, so most users had no signal via carrier.  I did not 
get a packet capture yet to see what could be going on, we’re 99% sure we’re not blocking traffic.  I’m wondering if 
the phones have an algorithm to test wi-fi signal, and perhaps the carriers will blacklist public IPs with known wi-fi 
calling issues to avoid cases where an emergency call can’t be made because of intermittent bad performance?  It seems 
odd that even when no bandwidth issues exist, it’s not attempted.

 

Thoughts?

 

Thanks,

 

Chuck Church