[VoiceOps] IPAWS/FEMA National Test - VoWIFI

Fri Oct 6 14:18:53 EDT 2023

The alert was also not received on my DISH phone, a Project Genesis device
that was on native DISH 5G.

On Wed, Oct 4, 2023 at 4:33 PM Nathan Anderson via VoiceOps <
voiceops at voiceops.org> wrote:

> ...huh.
>
>
> https://cacm.acm.org/magazines/2021/10/255719-securing-the-wireless-emergency-alerts-system/fulltext
>
> Guess it is delivered over a separate interface to the MME than SMS would
> be.
>
> Kinda boggles the mind that "WEA over IMS" isn't a thing.
>
> Perhaps it's an issue of scalability?  WEA messages over NAS presumably
> doesn't require that much overhead: MME sends the message out to all eNBs,
> who in turn I'd guess would just indiscriminately transmit it to all
> attached UEs.  More broadcast-y than unicast-y.  Whereas I guess an
> IMS-based solution would require the CSCF to enumerate all active
> registrations and then transmit a SIP message individually to each
> subscriber, one-by-one.
>
> Still, the lack of at least some IP-based way of accomplishing this seems
> like a huge oversight, especially in an age where it seems like more people
> (especially in more rural areas) are more reliant on VoWiFi than ever
> before in order to have any use whatsoever of their mobile voice service
> while at home.
>
> -- Nathan
>
> -----Original Message-----
> From: VoiceOps [mailto:voiceops-bounces at voiceops.org] On Behalf Of Nathan
> Anderson via VoiceOps
> Sent: Wednesday, October 4, 2023 3:53 PM
> To: voiceops at voiceops.org
> Subject: Re: [VoiceOps] IPAWS/FEMA National Test - VoWIFI
>
> Darn...it actually had occurred to me to test this very thing by forcing
> airplane mode and then enabling WiFi, but then spaced it and didn't manage
> to do that before the broadcast went out!
>
> Assuming I'd actually managed to run the test, I was actually fully
> prepared to be surprised if I had NOT gotten the test broadcast while
> exclusively on WiFi Calling.  It seems bizarre to me to learn that WEAs are
> dependent on the same NAS CP messages that non-IP-based SMS over LTE is
> also dependent on...can this really be true??  This is strange because it
> would require that all mobile carriers continue to run and maintain a 2G
> core, since (as far as I know) SMS can only be encapsulated within LTE NAS
> by way of the SGs interface.  (Perhaps there is some separate interface
> over which WEA payloads specifically are sent to the MME?)
>
> Some months ago -- but well after the 3G UMTS shutdown had taken place --
> I found that my ability to use SMS on the AT&T network had suddenly broken
> in a weird way, and ONLY worked over WiFi.  Which was naturally a *wee* bit
> inconvenient.  After digging into it over a few days, I figured out that
> the SMS over IP (IMS) setting in my (non-5G) handset's baseband was
> disabled.  And apparently this setting is ignored when you are on VoWiFi,
> since IMS is literally the only way to deliver SMS over ePDG.  I enabled it
> & that fixed my problem with SMS over LTE.  I did some back-and-forth
> testing and every time I re-disabled that baseband setting, SMS over LTE
> broke again.  I took this all as a sign that AT&T was probably looking to
> retire their entire 2G/3G core, though admittedly I haven't tried forcing
> the same handset back to SMS-over-SGs since then in order to see if maybe
> this was just a temporary (yet prolonged) glitch on their side.
>
> -- Nathan
>
> -----Original Message-----
> From: VoiceOps [mailto:voiceops-bounces at voiceops.org] On Behalf Of Jay R.
> Ashworth via VoiceOps
> Sent: Wednesday, October 4, 2023 2:08 PM
> To: jra
> Cc: VoiceOps
> Subject: Re: [VoiceOps] IPAWS/FEMA National Test - VoWIFI
>
> I now have a counter report that the Cellular Control Channel necessary to
> get
> these alerts to a cellphone *is not proxied by carrier WIFI-connect*, by
> design.
>
> I'm familiar with his credentials, and I'll assume he knows what he's
> talking about,
> cause *I* know what he's talking about, and he sounds like he's talking
> sense.  :-)
>
> Thanks to everyone who responded.
>
> If you *did* get an alert, *and you know you were not in range of ANY cell
> network*,
> only WIFI proxy, that wasn't supposed to be possible and I would still
> like to hear
> about that.
>
> Cheers,
> -- jr 'just zis guy, you know?' a
>
> ----- Original Message -----
> > From: "Jay R. Ashworth via VoiceOps" <voiceops at voiceops.org>
> > To: "VoiceOps" <voiceops at voiceops.org>
> > Sent: Wednesday, October 4, 2023 3:25:04 PM
> > Subject: [VoiceOps] IPAWS/FEMA National Test - VoWIFI
>
> > I have a report from a usually reliable source that he did not receive
> today's
> > IPAWS/CMAS/WEA test message, and he surmises this might be because his
> phone
> > handset is forced to VoWIFI.  I have a number of other reports, mostly
> though
> > not all, from the broadcast engineering community; nobody reported
> expecting
> > a CMAS and not getting it, so that's not data here.
> >
> > Is anyone on the list involved with the FEMA/IPAWS/CMAS link, or knows
> someone
> > who is, and has a channel to clear this query up through?
> >
> > I could be unsurprised to find that the carrier VoWIFI proxies missed
> out on
> > proxying SMS Cell Broadcast, which I gather provides the underlying PHY
> for
> > CMAS.
> >
> > Cheers,
> > -- jra
> >
> > --
> > Jay R. Ashworth                  Baylink
> jra at baylink.com
> > Designer                     The Things I Think
>  RFC 2100
> > Ashworth & Associates       http://www.bcp38.info          2000 Land
> Rover DII
> > St Petersburg FL USA      BCP38: Ask For It By Name!           +1 727
> 647 1274
> > _______________________________________________
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> > VoiceOps at voiceops.org
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>
> --
> Jay R. Ashworth                  Baylink
> jra at baylink.com
> Designer                     The Things I Think                       RFC
> 2100
> Ashworth & Associates       http://www.bcp38.info          2000 Land
> Rover DII
> St Petersburg FL USA      BCP38: Ask For It By Name!           +1 727 647
> 1274
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