Slashdot Mirror
Apple's Dual-SIM Tech Ruins Verizon Coverage (pcmag.com)
Apple's new dual-SIM function, which lets iPhone XS, XS Max, and XR owners use two cellular subscriptions at once, will come to new phones today. But the current implementation will have a huge negative impact on Verizon subscribers who choose to use dual-SIM in the US, PCMag reported Tuesday, citing engineers who have seen early builds of the software. From the report: Dual-SIM, a popular feature in the rest of the world, is largely unknown in the US. Generally, it's used for three things: roaming internationally, where you get a foreign SIM and also keep your local number; having home and work lines on one phone; or trying out multiple domestic services to see which one is better. Apple's dual-SIM relies on one physical SIM and an "electronic SIM" or eSIM, which is activated from a menu or an app. AT&T, T-Mobile, and Verizon promised eSIM support at launch, but neither Verizon nor T-Mobile will support the eSIM right now. T-Mobile is working on it and will support eSIM when its software is ready, the carrier told me.
[...] The problem comes when a physical Verizon SIM is pushed into the "secondary" position while the phone is in the US. Under the current software build, that kicks the Verizon connection down to 2G CDMA, an old network with significantly less coverage than the current LTE network. The old network also has no MMS support, and certainly wouldn't work for FaceTime. So Verizon customers may find they have perfectly good coverage with their SIM in "primary" position, but no signal and fewer features with the SIM in "secondary." When I asked Verizon about the CDMA network, the company said that 30 percent of its cell sites were now LTE-only, so there would be a definite coverage hit.
[...] The problem comes when a physical Verizon SIM is pushed into the "secondary" position while the phone is in the US. Under the current software build, that kicks the Verizon connection down to 2G CDMA, an old network with significantly less coverage than the current LTE network. The old network also has no MMS support, and certainly wouldn't work for FaceTime. So Verizon customers may find they have perfectly good coverage with their SIM in "primary" position, but no signal and fewer features with the SIM in "secondary." When I asked Verizon about the CDMA network, the company said that 30 percent of its cell sites were now LTE-only, so there would be a definite coverage hit.
How is this Apple's fault? This is 100% on Verizon. Verizon controls what network a device can connect to. MAYBE Apple's eSIM shit is wonky in some way, but since it works on 2G, that means Verizon can at least get the basic details from the SIM and talk to the device. That means they can associate it with a customer account and can put it on the proper network.
This is Verizon's fault.
More like CRAPPLE!
That summary sounds like the problem is with Verizon, not with Apple.
Always pioneering in things others have been doing for years.
Just like rounded corners, touch screens, and smart phones.
Under the current software build, that kicks the Verizon connection down to 2G CDMA
Sounds like a clever way to rate-limit the data connection to avoid data overrages.
Actually, it is probably with Apple, since the second SIM only supports 2g and no MMS? How are you supposed to comparison shop when one has such limitations?
I'm not sure if this is an Apple code, something an update can fix, or if this is common on dual sim phones?
The article says that it is a software issue. Article says Dual-SIM phones are not a thing in the USA, and I've never heard of them before now,... So, extrapolating from that I would say that this is indeed a "common issue" for Dual-SIM phones in the USA...
Google Fi uses eSim to access T-Mobile and Sprint, starting with the ancient Nexus and xconttinuing through the Pixel. So, no, not T-Mobile's fault.
Still a nope. The secondary position only switches to that band because of the US network. Reread the article and you'll note that pushing the SIM into secondary outside of the US works just fine. The thing to note is that when you push a SIM into the secondary position, the device will attempt to ask the cell service to allow only inbound calls, since all outbound calls are done via the primary. Apparently, US cell networks explode in a puff of "WAAAA??" when asked to do this, and just go lowest common denominator in the confusion.
In short, asking a US carrier to provide an "inbound only" line is witchcraft and the iPhone just deals with the mass pandemonium as best as can be expected.
Pubes.
The way this works internationally is that you have two SIMs (usually actual SIM cards, not eSIMs) and you can choose which SIM is used for what. In some phones, the SIM card slots are hardwired for use with the different radios, so for example a SIM in slot 1 can be used with 2G, 3G or 4G, but a SIM in slot 2 can only be used with 2G. To use the second SIM with 3G or 4G, you would have to swap the actual SIM cards around. In more modern phones, the SIM cards are assigned to the radios by software, but typically you can still only use one of the cards on 3G or 4G, while the other card is used for voice only and limited to 2G, maybe 3G. There are also phones where only one card can be actively used at a time, so for example if you get a call on the card that is not used for data, you lose the data connection for the duration of the call. There are many different ways dual-sim is implemented.
The story sounds like the phone can dynamically assign the actual SIM card and the eSIM to the radios, but one of the radios is 2G-only. Without support for the eSIM by Verizon, that's the only way to assign the SIM card to the secondary radio, and if that causes a downgrade, then it must be a limitation of the radio, i.e. the phone.
Apple is rolling out unfinished technology.
Not unfinished on Apple's side though. Works fine in Europe.
All that is unfinished is the U.S. carrier side, where carriers are dragging feet. I think Apple has done the right thing, which is to release it as is and let carriers start to take support calls based on shoddy or incomplete network support for what is a standard feature is many other countries...
"There is more worth loving than we have strength to love." - Brian Jay Stanley
more fashion than tech.
Actually, it is probably with Apple, since the second SIM only supports 2g and no MMS
By that logic, your up-to-date browser is at fault for using an old encryption method to talk with a site that hasn't yet been updated to work with newer encryption.
Just as a browser will fallback to an older method in order to talk to a site that hasn't been updated, the eSIM is falling back to what little support it has until the carriers add full support.
This is Trump's fault
What?
This is 2018. How do you not have LTE on both sims?
This was a restriction dual sim phones used to have like 5 years ago
The fact that Sprint (same wireless tech as Verizon) and AT&T (same wireless tech as T-Mobile) are *not* mentioned makes me wonder if this is a tower firmware bug that will be fixed soon.
Check out my sci-fi/humor trilogy at PatriotsBooks.
Unless Apple chose a proprietary esim? Because, I don't know, they want to be like Microsoft was in the 90's with a "we're big enough for everyone to follow our stuff and not established standards" attitude?
WTH canâ(TM)t Apple just launch their own MVNO? Iâ(TM)ve been using a Google Fi SIM in my iPhone for the last ~18 months and could not be happier.
It is not. Lumia 950 dual SIM had the same issue on AT&T's network. One SIM had to use the 2G network, so the second SIM was only usable on carriers with 2G network.
OP forgot to list the fourth reason which is maintaining a secret second number for the purpose of having an affair. Side hoe 101.
It's truly ludicrous that outside of North America, dual SIM phones are the norm, whereas in NA, it is impossible to buy a phone from a carrier that is dual SIM (at least that's the case in Canada). That kind of nonsense is the result of having oligopolies. I voted with my wallet and bought a dual SIM Xiaomi from a third party. Will likely do so next time I need a phone as well.
Google Fi uses eSim to access T-Mobile and Sprint, starting with the ancient Nexus and xconttinuing through the Pixel.
The pixel 2 eSIM will not work *at all* on t-mobile, let alone at slow speeds. I've heard the same complaint regarding verizon as well.
So yes, this is totally a t-mobile/verizon problem.
If as you say the pixel 3 fixed this, then that's great - but I do have my doubts.
This article from 5 days ago says pretty much the same thing:
https://www.androidauthority.com/google-pixel-3-esim-918312/
However, the three major U.S. carriers which have stated they will support eSIM tech - Verizon, AT&T, and T-Mobile- do not currently have systems in place to support eSIM, at least not yet.
For the time being then, the Pixel 3 eSIM will only work with Project Fi and other select global carriers which support the tech. But at least you can rest assured that at some point in the future it will work here at home on at least three of the Big Four carriers.
They are not a big thing here, but they have been available here & there.
A few years back I carried a Lumia 950 XL which had dual sim support. It was useful when traveling abroad I could put home T-Mobile SIM in the secondary slot and still be able to send/receive calls/texts from home on my main number, and put a local SIM in the primary for high speed data.
Originally I'd planned to keep the home sim in the primary slot, only ran into an issue like what this describes, that the secondary SIM was limited to non LTE connections.
I can't say where the disconnect is, but Google Fi *is* T-Mobile (and Sprint). How can Fi use T-Mobile towers with eSim, but T-Mobile can't use T-Mobile towers with eSim. Maybe I'm no expert here, but that doesn't sound like a strictly technical problem.
I'm entering this post on a Pixel 2 with no sim card, connected to a T-Mobile tower (LTE), so pretty sure it works.
This is how most dual sim phones have worked. Your primary sim provides LTE data/voice services the secondary just provides 2g voice and texting services.
The difference with every other dual sim phone is they used physical dual sims, you could easily swap which sim was providing your LTE data services.
Verizon users now have to utilize their Verizon SIM as the primary. As such, Verizon stands to see users utilizing their network as the primary more often and therefore, their data, which they can then charge more for...I don't see this getting solved quickly.
"Don't meddle in the affairs of a patent dragon, for thou art tasty and good with ketchup." ~ohcrapitssteve
Actually, it is probably with Apple, since the second SIM only supports 2g and no MMS? How are you supposed to comparison shop when one has such limitations?
I don't follow. Why would Apple care whether you are on Verizon, AT&T, T-Mobile, or some other network? If anyone would want to make it more difficult to comparison shop between telcos, it would be the telcos themselves.
I can't say where the disconnect is, but Google Fi *is* T-Mobile (and Sprint). How can Fi use T-Mobile towers with eSim, but T-Mobile can't use T-Mobile towers with eSim. Maybe I'm no expert here, but that doesn't sound like a strictly technical problem.
I'm entering this post on a Pixel 2 with no sim card, connected to a T-Mobile tower (LTE), so pretty sure it works.
That's the thing, I don't know where the disconnect is either, but I have a pixel 2 and do NOT have google-fi.
Three t-mobile reps have all stated I can not use eSIM with them, they do not sell eSIM access, and the only way to use the phone with their service/accounts directly is to get a physical SIM (Which to their benefit was offered to me for free)
When searching around to figure out WTF, every forum post I came across was people saying the same thing.
When it comes to esim I'm no expert either, but all I gather is that it isn't a problem at the tower end, but is within t-mobiles network.
A sim identifies both you as a subscriber as well as to what carrier.
The towers must be allowing both t-mobile and google-fi identifications to authenticate and route to the right place properly, but yea it kinda does sound like t-mobile not able to route t-mobile tower traffic to them with eSIM like they do with normal SIMs.
If you launch your eSIM Manager, you should see clearly that it can support switching carriers separately from what towers/radios it uses to get there.
So where ever the problem is, it is within t-mobile not allowing it, with the claims they are still setting up esim tech on their network.
However for an additional fee . . .
Wow, that's completely wrong. I have a Pixel 2 XL, my wife and daughter both have a Pixel 2 (non XL version). All are on Google Fi which uses T-Mobile primarily in my area (it falls over to Sprint and even to us-cellular when the signal is better on those). And they all use e-SIM and they all work fine. LTE connections, good speed, etc.
>> WTH canâ(TM)t Apple just launch their own MVNO?
Because they want to sell phones to all their primary customer which are the carriers, not alienate them !
aaaaaaa
It varies by device, my current phone from Nokia limits the 2nd SIM slot to 3G speeds, no LTE, only the 1st (primary) slot gets LTE access.
Wow, that's completely wrong. I have a Pixel 2 XL, my wife and daughter both have a Pixel 2 (non XL version). All are on Google Fi which uses T-Mobile primarily in my area
So google-fi service can use esims on t-mobile towers.
But t-mobile service can NOT use esims on their own towers, which isn't completely wrong, or wrong at all, and t-mobile representatives will out right tell you this if you try to get esim on your t-mobile account to work.
My t-mobile service can also use at&t towers without having an at&t account, so that's hardly the surprising part.
The surprising part is that t-mobiles own carrier service can't use esims on their own towers, when their own towers support it. The problem must be further back on their network.
Go ahead and try to sign up for t-mobile esim service on any of your pixel 2's, you'll find they will not sell that to you and claim they don't support it on their end, which not at all clearly means their service/carrier end, not their towers.
Apple is dual-LTE dual-standby when both operators are pure 3GPP (GSM/UMTS/LTE/NR) instead of 3GPP2 (CDMA) plus 3GPP (LTE). Getting CDMA and LTE to work in Android phones years ago was a fucking clusterfuck for OEMs.
Provisioning. T-Mobile doesn't have the system in place to remote-provision a eSIM. Project Fi works by using their own infrastructure to constantly reprovision the (e)SIM (this is also done for their traditional SIMs.)
Because Project Fi uses multiple subscriber identities (basically multiple independent SIM cards rolled into one, one for each underlying network - T-Mobile, Sprint, and US Cellular) and dynamically swaps them out throughout the day, they have to handle this themselves instead of relying on regular carrier procedures.
I had a job which forced me to use a company provided phone. This resulted in me carrying my personal phone and the work phone. So I looked into the whole dual SIM thing so I only needed one phone.
Basically none of the mobile providers in Australia would supply a dual SIM phone. Looks like they were scared of the competition and didn't want you to have a competitors SIM in your phone with theirs that you purchased through them. The only real option was to buy a phone outright through a non-telco provider and even then, a number of the models were grey imports from China.
Multi-SIM phones aren't common in the US because of incompatible networks and frequency bands, and a drive (by American consumers) for high-speed mobile data.
Most multi-SIM phones limit one or more SIMs to 2G GSM only, which limits those secondary SIMs to the T-Mobile network in most locations. (There are other 2G GSM networks, but ALL of those others are small regional networks with seriously limited coverage, and T-Mobile already has roaming agreements in place with all of them.)
Getting LTE and CDMA working in the same phone on a single SIM involved enough hacks as it is (this is why Verizon's earliest global phones used the SIM solely for the GSM modem and kept the CDMA modem totally separate, it took OEMs years to work out all the bugs). Getting it working over multiple SIMs is, of course, going to be a nightmare.
The rest of the world avoids this by:
As a theoretical discussion, why would the phone announce where it is pushing outgoing calls? Why would the network need to know at all?
It's not to do with "US networks" and the phone isn't trying to tell the network to refuse outbound calls. It's due to glitchiness in handling 3GPP and 3GPP2 networks at the same time in the same baseband modem.
Thanks for the info! So while Google may be better than others at this, and it probably isn't trivial, it sounds straightforward to implement. It's back-office stuff rather than infrastructure. It still seems as if T-Mobile could do this if they really wanted to? If so what's their downside to doing (or not doing) it?
Hell, let me add this: Verizon's earliest global phones were "technically" dual-SIM. The CDMA modem and GSM modem could function (although the firmware programming for this was absent) simultaneously and independently and used two independent subscriber identities.
From the perspective of the firmware, it was just two independent cell modems, and was handled much the same as a dual-SIM phone was, although with the hacks to make them appear as one for the sake of delivering the user experience Verizon sold the end user on.
Verizon wants this, because then you'll make Verizon your primary SIM.
That's an issue or limitation common to all dual SIM phones except the newer ones.
My favorite phone is 2G dual SIM, so I don't care too much either way.
OnePlus 5T does ATT as SIM1 & VZW as SIM2. No problem.
Apple's dual-SIM relies on one physical SIM and an "electronic SIM" or eSIM, which is activated from a menu or an app. AT&T, T-Mobile, and Verizon promised eSIM support at launch, but neither Verizon nor T-Mobile will support the eSIM right now. T-Mobile is working on it and will support eSIM when its software is ready. If anyone face printer error clicks here https://www.hpsupporthelpline....
3. Having consumers that are perfectly happy with their mobile internet running at 90s dial-up speeds
Huh? Can you explain this one? From a technical point of view that is. From a human consumer point of view you don't need to explain because it's completely wrong and shitty EDGE is not tollerated much less makes people "happy"
3. Having consumers that are perfectly happy with their mobile internet running at 90s dial-up speeds (EDGE speeds in practice do not go over 70kbit/s on a moderately-used cell site)
I take it you don't travel much.
Wouldn't the solution to this be to have Verizon as the physical SIM, and the GSM 2G carrier the eSIM?? Unless someone's trying to carry both Verizon and Sprint?
I wonder why, though. I mean, what problem is there to register for a standard 2-way, inbound+outbound, and simply not route any outbound data to the 2nd sim? It's the phone that decides which SIM the outbound data is pushed to. Never push any to 2nd sim, problem solved.