ingenium

I imagine if the phone supports it, and it's not throttled, they would allow CA (though T-Mobile could disable it). When roaming internationally, my Pixel engaged CA in multiple countries. Sent from my Pixel 2 XL using Tapatalk

Hmm. I mean the APN settings show IPV4V6, which I think is default full stack. IPv6 only I believe uses IPV6 (I setup a T-Mobile APN this way once, and I received only a v6 address and it tunneled v4). Typing in an IPv4 address works fine, but this would work even with 4to6. If Google wasn't working on that address in your last post, it's likely because of the way they have their webserver setup (you can set it so it requires a domain name in the request to know which site you want. This is normal for hosting multiple domains on a single IP, especially behind a load balancer. Called SNI). For what it's worth, it's possible LTE modems are only able to get either a v4 or a v6 address but not dual stack on Sprint. I have a Sierra Wireless MC7455 using r.ispsn, and I can only get a v4 address on it even though it's setup for dual stack and that APN should give out both. Sent from my Pixel 2 XL using Tapatalk

It's the same IP range I normally see from Sprint. It is suspicious that it starts with 192, but that's the range I've seen assigned for a long time. This was also while connected to my Airave. Sent from my Pixel 2 XL using Tapatalk

But why not just use the T-Mobile PLMN? Unless this is how they decided to control which sites allow roaming? It still seems odd though, no other roaming partners do this to my knowledge. Unless that's the way T-Mobile implements roaming for some reason, by using a PLMN of the partner. Sent from my Pixel 2 XL using Tapatalk

Not true. My phone uses x.ispsn and I have verified that I have a non-routable (ie NATed) IPv4 address and a routable IPv6 address assigned. It's possible it dictates which pool of NATed IPv4 addresses it uses, but both are assigned for use on LTE. Sent from my Pixel 2 XL using Tapatalk

No Sprint has been tuning their LTE roaming lately. Sometimes it will switch to AT&T roaming instead of going to 3G. I had this happen in Berkeley, CA few weeks ago. Presumably it's a way to make VoLTE more reliable. Ideally they would have it prefer roaming LTE vs native 3G only while on a call, unless the roaming doesn't count towards your roaming allowance. Sent from my Pixel 2 XL using Tapatalk

Interesting! So it would seem TMobile may be broadcasting the Clear PLMN? Maybe it's part of the roaming/integration plan? Also interesting that it still shows as roaming, even though it's using a "native" PLMN. I would have assumed that was used to determine if the R indicator should be shown, but apparently not. Sent from my Pixel 2 XL using Tapatalk

Interesting. Is it stable with that PLMN? Speeds? Sent from my Pixel 2 XL using Tapatalk

That is weird. I never had an issue with my Pixel 1 on my Airave, and my bf uses it now and also doesn't have an issue (to my knowledge anyway). So it could be something with your particular device. You can always try wiping provisioning data and letting it setup again. Or if you have a non Sprint SIM, put that in briefly. When I had issues with RCS not appearing on my Pixel, nothing would fix it other than swapping the SIM. That seems to force some kind of reset that 72786 doesn't. Regarding the channel, yeah that's normal on the 3.0. The 2.5+ I believe used the same channel as the macro, but my 3.0 has always had 1x in the internal LTE guard band. For for example, if B25 is 1985-1995 MHz, the 1x carrier will be centered on 1985 MHz. Sent from my Pixel 2 XL using Tapatalk

Interesting that eCSFB isn't working on the Airave for you. That was kind of the whole point of the 3.0. So you just miss calls because it never rings? Or it rings and the call won't connect when you answer? I wonder if there's a way to force SRLTE to always be active on the OG Pixel... Normally it only engages with a weak signal because it disables CA on that SoC (Snapdragon 835 phones can do 3xCA + SRLTE with CDMA, so no eCSFB necessary). But CA obviously isn't needed with an Airave. It might be possible with QPST or something like that. Sent from my Pixel 2 XL using Tapatalk

How long have you had it? It should eventually learn the RF environment, and learn what is available in places that you frequent. It's stored in the modem. You can try wiping provisioning data (*#*#72786#*#*) and that may clear this cache and force it to start fresh. Also, what band is the phone connected to? I've noticed that phones prefer a weak macro b41 signal to the magic box, and my Pixel 2 XL regularly switches from my magic box to a weak macro signal in areas of my house where I pick it up. Once it drops to b25 or 26 it immediately goes back to the magic box. It's possible the S9 is better at holding the macro b41 signal than the s8+. Sent from my Pixel 2 XL using Tapatalk

You can probably do it if you block access to the ipsec VPN server that the LTE side uses. I did a packet capture on my router when I powered on the Airave. The CDMA side seems to do a DNS lookup for either segw01.femto.sprint.net, segw02.femto.sprint.net, ...., or segw10.femto.sprint.net (10 possibilities, not sure how it picks one each time it boots up). And then establishes an IKEv2 VPN tunnel to it. The LTE side does not seem to do a DNS lookup (maybe the it does it via the first tunnel?), however in my case it established a second IKEv2 tunnel to 68.31.0.1. That IP address seems to "neat", so maybe it's hard coded. You can try blocking access to that IP at your router, which would prevent the LTE side from working. Interesting tidbit, the AIrave also looks up its assigned hostname (via DHCP) in DNS for some reason. And also first does an NTP check for time.localdomainname (where localdomainname is whatever your local domain is set as in your DHCP server). If that fails, it then queries the ntp pool. After these two things, it proceeds to the CDMA DNS lookups and establishing that ipsec tunnel.

The aggressive roaming seems to have mostly stopped for me. I've been dropping to 3G (or just 1x) in Sprint dead spots where I know AT&T has a good LTE signal. Sent from my Pixel 2 XL using Tapatalk

I don't think that's the case. For me, SCP will correctly show WCDMA, HSPA, and EDGE (didn't have a WCDMA screenshot easily accessible). Sent from my Pixel 2 XL using Tapatalk

That's true, they could deploy 1.4 MHz b26 and reserve it basically just for VoLTE. Sent from my Pixel 2 XL using Tapatalk

Ahh right, I forgot it drops to 2 4t4r chains when they go beyond 3 carriers. Sent from my Pixel 2 XL using Tapatalk

Future proofing how? Massive MIMO are integrated units. Would they do physical split sectors for b41? I'm just not sure what the extra 8T8R could be used for. Sent from my Pixel 2 XL using Tapatalk

Interesting. I think SCP is incorrect here. AT&T shut down their GSM network a year ago. It's only WCDMA/HSPA and LTE now. Sent from my Pixel 2 XL using Tapatalk

I had a panic moment doing a firmware upgrade on my mc7455. As soon as it finished flashing, it it triggered a BSOD. Buggy Sierra Wireless upgrade driver apparently. Thankfully the firmware flashed OK. For what it's worth, it's apparently possible to flash the modems with a third party open source Linux tool. It should be easy to install in Ubuntu 18.04, so you might want to try that route going forward. It might be more reliable. Sent from my Pixel 2 XL using Tapatalk

I just did a packet capture on my Airave (which should use the same servers as wifi calling), and it connected to segw06.femto.sprint.net for the ipsec tunnel (ports 500 and 4500). It established two tunnels (one for LTE, and one for CDMA) to IP addresses 68.28.116.127 and 68.31.0.1 So you can likely try to explore their DNS records to build an IP list. Sent from my Pixel 2 XL using Tapatalk

Ahh, you're doing a larger scale network, not a home network. I don't think you'll be able to get an IP list from Sprint. They probably have a domain name that is used, and likely has many A records (or may only return 1 for load balancing reasons, preventing you from getting a list. Amazon Alexa does this for example). You could maybe sniff DNS lookups from an Airave when it's powered on, or when WiFi calling is toggled, to see if that's one way to get all the IPs. I suppose you could allow port 4500 to any IP in Sprint's allocation (should be public somewhere). It's possible that someone might have a routed IP (hotspot plan) and decide to host an ipsec tunnel to bypass your filters, but I'd say the odds are fairly low. Regular plans have non-routable IPs so can't host servers. Sent from my Pixel 2 XL using Tapatalk

They likely have many IP addresses as endpoints. It might be a whole subnet that you can map. But I'm not sure why you're manually adding firewall rules with the IP address? Sent from my Pixel 2 XL using Tapatalk

If that's true, then this makes perfect sense. Maybe someone jumped the gun and rolled it out before T-Mobile roaming was flipped on. I don't believe it's active anywhere currently. Sent from my Pixel 2 XL using Tapatalk

I noticed a bit over a week ago that I briefly switched to att LTE roaming in Berkeley, CA in a weak area. I thought it was just an odd fluke. It would make sense that this is a way to make VoLTE much more reliable. And perhaps they'll prioritize T-Mobile roaming (and maybe not have it count towards roaming allotment?). Ideally they'd be able to make it skip Sprint 3G only if on a call rather than all the time, to avoid using up your roaming allowance needlessly (and since LTE roaming is throttled slower than 3G). Sent from my Pixel 2 XL using Tapatalk

Because public WiFi has an ongoing maintance cost, plus the cost to set it up and properly isolate it from your network. The magic box is just easier. You aren't responsible for it. The magic box (via LTE) also has vastly superior QoS so that one person won't bog it down. My parents house is one place where a magic box works amazingly. Their only internet option is 3 mbps DSL. B26 only on phones, and that's upstairs only. The magic box latches on to b25 and provides 15-30 Mbps consistently. They actually use it now with a Sprint mobile broadband plan. For some people, the magic box is a better solution than an Airave or wifi calling (which won't work well on 3 mbps DSL if someone is using the internet). For businesses, it's a $0 cost, easy deployment to help customers. And they aren't responsible for what people do on it. Sent from my Pixel 2 XL using Tapatalk