Is iMessage more reliable than SMS?
May 8, 2022 6:01 AM Subscribe
I have an android phone. Every once in a while I find that text messages I send or receive just don't arrive. It's a weird and frustrating problem. It happens, I dunno, just a few times a year that I know of, but it'd sure be nice to be able to rely on SMS. Is iMessage any better on this front? I'm thinking of moving to iPhone and working on a Pros/Cons list...
If you're messaging with someone else who also has an iPhone, you can see if messages have been delivered, which is nice. (People can turn off read receipts but AFAIK you can always see "delivered" if it has been delivered.) But if you're messaging with someone who does not have an iPhone, it will send an SMS. If you're texting with specific people, you could both switch to something like Signal or Whatsapp (which won't be SMS but does require the recipient to also have that app.)
posted by needs more cowbell at 6:29 AM on May 8, 2022 [1 favorite]
posted by needs more cowbell at 6:29 AM on May 8, 2022 [1 favorite]
it'd sure be nice to be able to rely on SMS
In 2007 SMS failure rate was about 5%. At that point in history, multi-segment messages (that is, messages with more than 160 characters) were a thing but with mixed support on devices and networks. MMS was likewise somewhat unevenly supported. This number acts as kind of a proxy for the reliability of the underlying message transport.
These days, multi-segment messages are a thing and widely supported. MMS is heavily used. In 15 years network reliability has improved but the complexity of the average message exchange is higher. Anecdotes seem to suggest that the SMS failure rate is hovering around 2% these days.
I don't think anyone has really looked at the reliability of the iMessage infrastructure, but there are a few factors that might affect your decision to use it:
The transport is TCP rather than SMS. This means you have to have an internet connection. An internet connection is not the same thing as being able to talk to the tower.
Because it isn't a telephone thing, iMessage can be used on devices that aren't telephones: tablets and computers.
The protocol is totally orthogonal to SMS. You're not at the whim of SMS' "send and forget" architecture and there's vendor owned infrastructure actively trying to deliver messages.
It's a closed protocol on closed systems.
The way iMessage identity works is... weird. It's a phone number thing. Or an email identity thing. Or an iCloud account thing. Or some combination of the above.
SMS doesn't support read receipts, which can be a good thing or bad thing depending on your needs.
Judgy iOS people won't see you as a green text person. You are allowed to not care about this.
posted by majick at 6:36 AM on May 8, 2022 [2 favorites]
In 2007 SMS failure rate was about 5%. At that point in history, multi-segment messages (that is, messages with more than 160 characters) were a thing but with mixed support on devices and networks. MMS was likewise somewhat unevenly supported. This number acts as kind of a proxy for the reliability of the underlying message transport.
These days, multi-segment messages are a thing and widely supported. MMS is heavily used. In 15 years network reliability has improved but the complexity of the average message exchange is higher. Anecdotes seem to suggest that the SMS failure rate is hovering around 2% these days.
I don't think anyone has really looked at the reliability of the iMessage infrastructure, but there are a few factors that might affect your decision to use it:
posted by majick at 6:36 AM on May 8, 2022 [2 favorites]
The iMessage "Delivered" indicators are not reliable (in both directions: I have seen messages marked "Delivered" that weren't and messages not marked "Delievered" that were, though the latter possibly as SMS).
posted by likedoomsday at 6:38 AM on May 8, 2022 [1 favorite]
posted by likedoomsday at 6:38 AM on May 8, 2022 [1 favorite]
I won't comment on the delivered/read receipts since I'm primarily not not an iMessage user.
As other mentioned, SMS and iMessage is built on two wholly different technologies. SMS is effectively an after thought in the secifications for how modern mobile telephones communicate with cell towers. In the 80s, some mobile phone guys figured out that they could insert short text messages into the stream of the constant back-and-forth of cell phone and tower. Things have advanced a bit to support pictures, etc. but not much more than that. It was never designed to be a wholly reliable means of communication.
iMessage on the other hand is an internet protocol and depends on you have an internet connection (be it on a computer or iPad) or your mobile internet connection. It was more recently designed and thus thought more about reliability. It isn't perfect but what computer thing really is. Also, iMessage leverages SMS for people not using iMessage in the group chats.
In short, SMS is more universally useable as you can send and receive messages from almost everywhere...but you are depending on an old protocol not designed for reliability AND you are depending on the sending and receiving mobile phone networks to do the right things.
iMessage is more modern and more powerful and more reliable BUT all the benefits only exist when you have an internet connection and communicating exclusively with other iMessage users. In this case you are relying on Apple to do the right things to keep messages flowing.
posted by mmascolino at 6:54 AM on May 8, 2022
As other mentioned, SMS and iMessage is built on two wholly different technologies. SMS is effectively an after thought in the secifications for how modern mobile telephones communicate with cell towers. In the 80s, some mobile phone guys figured out that they could insert short text messages into the stream of the constant back-and-forth of cell phone and tower. Things have advanced a bit to support pictures, etc. but not much more than that. It was never designed to be a wholly reliable means of communication.
iMessage on the other hand is an internet protocol and depends on you have an internet connection (be it on a computer or iPad) or your mobile internet connection. It was more recently designed and thus thought more about reliability. It isn't perfect but what computer thing really is. Also, iMessage leverages SMS for people not using iMessage in the group chats.
In short, SMS is more universally useable as you can send and receive messages from almost everywhere...but you are depending on an old protocol not designed for reliability AND you are depending on the sending and receiving mobile phone networks to do the right things.
iMessage is more modern and more powerful and more reliable BUT all the benefits only exist when you have an internet connection and communicating exclusively with other iMessage users. In this case you are relying on Apple to do the right things to keep messages flowing.
posted by mmascolino at 6:54 AM on May 8, 2022
If you are going to be sending to large groups that have a mixture of iPhone and Android users, iMessage is often flaky.
For one-on-one message I've found it to be very reliable, regardless of the type of phone the other person is using.
posted by Winnie the Proust at 7:07 AM on May 8, 2022 [2 favorites]
For one-on-one message I've found it to be very reliable, regardless of the type of phone the other person is using.
posted by Winnie the Proust at 7:07 AM on May 8, 2022 [2 favorites]
iMessage is more reliable but only if you're messaging other iPhone users who are using iMessage. Otherwise it falls back to SMS and is as unreliable as Android's SMS, maybe a little worse. You may have a better experience with an iPhone if most of your friends have them too.
Android now has a private network like iMessage, it's called RCS. Rollout has been slow so it's still not in common use. But it is more reliable the way iMessage is more reliable. The differences between the three messages is explained in this article.
If you're mostly messaging a few friends see if you can get them to install Signal. It's yet another messaging system with a focus on security. Folks also use WhatsApp or Telegram as alternate messengers but I think Signal is the best of the bunch.
posted by Nelson at 7:07 AM on May 8, 2022 [1 favorite]
Android now has a private network like iMessage, it's called RCS. Rollout has been slow so it's still not in common use. But it is more reliable the way iMessage is more reliable. The differences between the three messages is explained in this article.
If you're mostly messaging a few friends see if you can get them to install Signal. It's yet another messaging system with a focus on security. Folks also use WhatsApp or Telegram as alternate messengers but I think Signal is the best of the bunch.
posted by Nelson at 7:07 AM on May 8, 2022 [1 favorite]
So, as others have said here, SMS works differently than literally every other smartphone messaging system, at the protocol level, and for that reason it has a few advantages and a few disadvantages.
The main advantage is that it is completely universal. It's baked into the cellular specification, so literally any phone that uses the cellphone network can send and receive SMS messages. Dumbphones, smartphones (on any OS), featurephones --- they all implement the exact same standard. Neither the recipient nor the sender needs to have a mobile data plan or even Interent connectivity over WiFi. If you have cellular voice, you have cellular SMS, period.
The main disadvantages are that, as part of its history as an afterthought to the cellular voice standards, it's an extremely primitive protocol. The way this becomes most conspicuous is of course the length limit, but a big under-the-hood crudity of it is that it has no mandated acknowledgment. That's not how most protocols (in particular TCP, which is the under-the-hood protocol for pretty much everything on the internet) work. Most protocols have a message-and-acknowledgment structure, where for every labeled datapacket the sender posts, the receiver then, if they got it, sends back an acknowledgment, and if the sender doesn't get the acknowledgment, they resend the packet (the labeling of packets makes losing an acknowledgment also not a big deal; the recipient accidentally gets it sent to them twice, realizes what happened, and ignores one of them). The important thing is that at the level of actual physical data-transfer, every single technology is fallible. For most things this is no big deal because on the protocol level this failure is detected and remedied. For SMS it isn't, which is why, every now and again, an SMS just disappears into a black hole.
Looking at other options (of which iMessage is not the only one!) they're near-universally built on top of internet-based TCP communication. This has the advantage that TCP, as described above, is a very reliable protocol for ensuring that data sent from point A actually arrives at point B; also, TCP-based technologies don't have the length limit* that SMS does. There are two major disadvantages. The first is that any TCP-based messaging service is an additional protocol layer (and likely associated app, and possibly even a centralized server) over and above TCP itself, and that specific protocol or app is not universally implemented; what's more, there are several of them, with limited intercompatibility. What should be done when you send an iMessage (or Signal, or WhatsApp, or whatever) to someone who doesn't have an account on these systems (if centralized) or doesn't have an app to interpret the message sent (if decentralized)? Some of the apps will then chunk it into SMSes, but then you're back to flinging packets into the darkness where you're no longer certain you'll get a response. Others will refuse to do it and insist your conversational partner needs to get their app, which they may not want to. The other disadvantage is that, as they use a fundamentally internet-based infrastructure rather than working through the same network used for cellular voice, anyone who doesn't use mobile data and isn't on WiFi can't participate in them.
The hybrid protocol of MMS (used by the native "messaging" app on most smartphones for sending pictures, audio, or video) uses, as I understand it, both technologies. The message itself is pushed to a server where it's made available over internet protocols (HTTP, itself over TCP); the intended recipient is notified over SMS that the message is available. The backend implements read-receipts so that when the recipient accesses the message on the server, the sender is informed that the message has been seen. This is extremely widely implemented (every smartphone and almost all featurephones have it implemented in their default messaging system; I assume the vanishingly tiny number of pure voice/SMS cellphones don't, as they wouldn't have internet-access capabilities), and the implementation is the same on every system. The main disadvantage is that, like TCP-exclusive methods, messages sent to users who are either temporarily or permanently not on the internet won't be received immediately.
*To be nitpicky, TCP in and of itself does have a length limit per packet, but anything that implements communication over TCP is capable of turning a message into packet-sized chunks and reassembling them on the far end.
posted by jackbishop at 7:58 AM on May 8, 2022 [1 favorite]
The main advantage is that it is completely universal. It's baked into the cellular specification, so literally any phone that uses the cellphone network can send and receive SMS messages. Dumbphones, smartphones (on any OS), featurephones --- they all implement the exact same standard. Neither the recipient nor the sender needs to have a mobile data plan or even Interent connectivity over WiFi. If you have cellular voice, you have cellular SMS, period.
The main disadvantages are that, as part of its history as an afterthought to the cellular voice standards, it's an extremely primitive protocol. The way this becomes most conspicuous is of course the length limit, but a big under-the-hood crudity of it is that it has no mandated acknowledgment. That's not how most protocols (in particular TCP, which is the under-the-hood protocol for pretty much everything on the internet) work. Most protocols have a message-and-acknowledgment structure, where for every labeled datapacket the sender posts, the receiver then, if they got it, sends back an acknowledgment, and if the sender doesn't get the acknowledgment, they resend the packet (the labeling of packets makes losing an acknowledgment also not a big deal; the recipient accidentally gets it sent to them twice, realizes what happened, and ignores one of them). The important thing is that at the level of actual physical data-transfer, every single technology is fallible. For most things this is no big deal because on the protocol level this failure is detected and remedied. For SMS it isn't, which is why, every now and again, an SMS just disappears into a black hole.
Looking at other options (of which iMessage is not the only one!) they're near-universally built on top of internet-based TCP communication. This has the advantage that TCP, as described above, is a very reliable protocol for ensuring that data sent from point A actually arrives at point B; also, TCP-based technologies don't have the length limit* that SMS does. There are two major disadvantages. The first is that any TCP-based messaging service is an additional protocol layer (and likely associated app, and possibly even a centralized server) over and above TCP itself, and that specific protocol or app is not universally implemented; what's more, there are several of them, with limited intercompatibility. What should be done when you send an iMessage (or Signal, or WhatsApp, or whatever) to someone who doesn't have an account on these systems (if centralized) or doesn't have an app to interpret the message sent (if decentralized)? Some of the apps will then chunk it into SMSes, but then you're back to flinging packets into the darkness where you're no longer certain you'll get a response. Others will refuse to do it and insist your conversational partner needs to get their app, which they may not want to. The other disadvantage is that, as they use a fundamentally internet-based infrastructure rather than working through the same network used for cellular voice, anyone who doesn't use mobile data and isn't on WiFi can't participate in them.
The hybrid protocol of MMS (used by the native "messaging" app on most smartphones for sending pictures, audio, or video) uses, as I understand it, both technologies. The message itself is pushed to a server where it's made available over internet protocols (HTTP, itself over TCP); the intended recipient is notified over SMS that the message is available. The backend implements read-receipts so that when the recipient accesses the message on the server, the sender is informed that the message has been seen. This is extremely widely implemented (every smartphone and almost all featurephones have it implemented in their default messaging system; I assume the vanishingly tiny number of pure voice/SMS cellphones don't, as they wouldn't have internet-access capabilities), and the implementation is the same on every system. The main disadvantage is that, like TCP-exclusive methods, messages sent to users who are either temporarily or permanently not on the internet won't be received immediately.
*To be nitpicky, TCP in and of itself does have a length limit per packet, but anything that implements communication over TCP is capable of turning a message into packet-sized chunks and reassembling them on the far end.
posted by jackbishop at 7:58 AM on May 8, 2022 [1 favorite]
One aspect of iMessage over SMS/MMS is, if you are messaging another iDevice, the message is end-to-end encrypted. It will not be, if you are messaging with someone on a non-iOS device, though.
posted by Thorzdad at 8:33 AM on May 8, 2022
posted by Thorzdad at 8:33 AM on May 8, 2022
For the record, most wireless carriers support SMS delivery reports. Sadly, one of the largest US carriers has chosen not to for about 20 years now.
posted by wierdo at 9:25 AM on May 8, 2022
posted by wierdo at 9:25 AM on May 8, 2022
I feel like I've seen a lot of questions here from iPhone owners or people trying to message iPhone owners about weird problems. Some of those questions can be found under this tag (but not all of them, because the person posting the question doesn't always realize the problem has to do with iMessage).
posted by trig at 10:11 AM on May 8, 2022
posted by trig at 10:11 AM on May 8, 2022
Oh, and I realize I didn't even talk about privacy, which is probably not a primary determiner for you but is another significant way messaging technologies differ. Both SMS and MMS are basically cleartext protocols where a reasonably motivated party with the right technology could read your messages. SMS is arguably more secure than MMS because it's ephemeral — if it's not intercepted in transit, it's gone and all anyone, even the cellphone provider, has is a record of when and to whom a message was sent. MMSes are kept on a server, so with the right warrant or data breach, your message could become public for some time after it's sent.
For the various TCP-based protocols, almost all of them use transport-layer security (TLS) when actually sending and receiving; the significant difference is whether they also have end-to-end encryption. Systems without end-to-end encryption will transmit them to and from a server in a way which can't be interecepted, but anyone who breaches the server might be able to see your messages. End-to-end encryption means that before they go to the server they're encrypted and after they're read off the server they're decrypted, so even a breach of the server only gets the eavesdropper the encrypted messages.
Broadly speaking, from a security perspective, if you want to conceal when and to whom you're talking, nothing will do that, really—all messages leave at least some indication of where and when they went. If you want to conceal what you're talking about from ordinary friends-and-family, and malefactors who aren't interested in you particularly, SMS, MMS, and end-to-end encryption protocols are safe (nobody, AFAIK, is breaching MMS servers). If you have a stalker who has access to serious cellsignal interception tech, I wouldn't use SMS or MMS. If you've attracted the attention of state-level actors with subpoena powers, definitely don't use MMS or a TCP-based system without end-to-end encryption; use SMS only if necessary.
posted by jackbishop at 10:46 AM on May 8, 2022
For the various TCP-based protocols, almost all of them use transport-layer security (TLS) when actually sending and receiving; the significant difference is whether they also have end-to-end encryption. Systems without end-to-end encryption will transmit them to and from a server in a way which can't be interecepted, but anyone who breaches the server might be able to see your messages. End-to-end encryption means that before they go to the server they're encrypted and after they're read off the server they're decrypted, so even a breach of the server only gets the eavesdropper the encrypted messages.
Broadly speaking, from a security perspective, if you want to conceal when and to whom you're talking, nothing will do that, really—all messages leave at least some indication of where and when they went. If you want to conceal what you're talking about from ordinary friends-and-family, and malefactors who aren't interested in you particularly, SMS, MMS, and end-to-end encryption protocols are safe (nobody, AFAIK, is breaching MMS servers). If you have a stalker who has access to serious cellsignal interception tech, I wouldn't use SMS or MMS. If you've attracted the attention of state-level actors with subpoena powers, definitely don't use MMS or a TCP-based system without end-to-end encryption; use SMS only if necessary.
posted by jackbishop at 10:46 AM on May 8, 2022
Have the contacts that you have trouble with switched from Android to Apple or vice versa? I had a problem when my wife switched from Android to Apple and was no longer getting any text messages from me. Here is the solution.
posted by COD at 3:37 PM on May 8, 2022
posted by COD at 3:37 PM on May 8, 2022
On the Galaxy s20 I can enable "Advanced messaging" which will show me (when texting other users with a Samsung phone using the feature, not sure about other Androids) if the message has been delivered or read or neither. Just FYI if that applies - might be of service to you or someone else.
posted by getawaysticks at 8:28 PM on May 8, 2022
posted by getawaysticks at 8:28 PM on May 8, 2022
Just to put in a note that if you expect to be messaging more people outside the North American iPhone bubble (i.e. Europe, Africa, most if not all of Asia despite the region-specific platforms, and their related diasporas), the standard messaging platform is a combination of WhatsApp or Telegram (some Signal), and neither of your options will even be in consideration at all, be they Android or iPhone users. But they're all based on internet protocols like iMessage, and pegged to your phone number.
posted by cendawanita at 12:43 AM on May 9, 2022
posted by cendawanita at 12:43 AM on May 9, 2022
One really annoying edge case for iMessage (unless they've fixed it since 2019):
Suppose you're in a foreign country with really expensive data costs, so you've got data turned off. You want to send a text to a friend who also has an iPhone. You can't.
The way this usually works: If you have iMessage enabled, and you have data or wifi, you can send an iMessage to someone else with it enabled. If they're offline, it'll go as SMS (if you've got that setting turned on). If you send to someone who's not on the Apple ecosystem or isn't signed into iMessage, it'll go as SMS. If you're offline yourself (no mobile data signal, no wifi), I believe it'll go as SMS (although not till you have a phone signal of some sort).
But if the reason you have no mobile data is that you've got it deliberately turned off, and you're trying to communicate with another Apple person, it'll tell you you can't send an iMessage because you've got mobile data turned off (and you're not on wifi). It will not offer you the option of sending an SMS instead.
If you disable iMessage at this point, it'll now tell you you can't send an iMessage to that person because you've logged out of iMessage. It will not offer you the option of sending an SMS instead.
If you try to turn iMessage back on, it won't let you, because you don't have mobile data turned on (and you're not on wifi).
If you try typing in the other person's phone number, it will recognise the contact and tell you you can't send an iMessage.
If you delete the contact altogether and type in the phone number... same thing.
This makes for a truly maddening experience on arriving at an airport in a country with expensive data: you're tired, you're jetlagged, you've got a heavy bag, and the #@!£#! phone won't let you send an SMS to the friend who's picking you up unless you also turn on mobile data, at which point it'll make up expensively for lost time with everything you've forgotten to lock down to wifi (background app refresh, email fetching, whatever).
posted by ManyLeggedCreature at 3:18 AM on May 9, 2022
Suppose you're in a foreign country with really expensive data costs, so you've got data turned off. You want to send a text to a friend who also has an iPhone. You can't.
The way this usually works: If you have iMessage enabled, and you have data or wifi, you can send an iMessage to someone else with it enabled. If they're offline, it'll go as SMS (if you've got that setting turned on). If you send to someone who's not on the Apple ecosystem or isn't signed into iMessage, it'll go as SMS. If you're offline yourself (no mobile data signal, no wifi), I believe it'll go as SMS (although not till you have a phone signal of some sort).
But if the reason you have no mobile data is that you've got it deliberately turned off, and you're trying to communicate with another Apple person, it'll tell you you can't send an iMessage because you've got mobile data turned off (and you're not on wifi). It will not offer you the option of sending an SMS instead.
If you disable iMessage at this point, it'll now tell you you can't send an iMessage to that person because you've logged out of iMessage. It will not offer you the option of sending an SMS instead.
If you try to turn iMessage back on, it won't let you, because you don't have mobile data turned on (and you're not on wifi).
If you try typing in the other person's phone number, it will recognise the contact and tell you you can't send an iMessage.
If you delete the contact altogether and type in the phone number... same thing.
This makes for a truly maddening experience on arriving at an airport in a country with expensive data: you're tired, you're jetlagged, you've got a heavy bag, and the #@!£#! phone won't let you send an SMS to the friend who's picking you up unless you also turn on mobile data, at which point it'll make up expensively for lost time with everything you've forgotten to lock down to wifi (background app refresh, email fetching, whatever).
posted by ManyLeggedCreature at 3:18 AM on May 9, 2022
My first smartphone was an iPhone (the iPhone "1", for what it is worth). I switched to Android a few years ago, mainly just to try something different (first an LG, then a Pixel). Missing/failed text messages are the main reason I moved back to an iPhone last year.
posted by Rock Steady at 1:07 PM on May 9, 2022
posted by Rock Steady at 1:07 PM on May 9, 2022
The iMessage "Delivered" indicators are not reliable (in both directions: I have seen messages marked "Delivered" that weren't
This is generally the result of the way iMessage supports multiple device delivery. "Delivered" means that it was delivered to at least one device on the account. It does not mean it was delivered to the device in the hand of the person who owns the account. If you happen to have an iDevice logged into the account, such as an old iPad, sitting at home on the wifi, and you are someplace with spotty data, iMessage can (and sometimes will exclusively) deliver your messages to the available device rather than the device you'd hope for.
posted by jgreco at 1:42 AM on May 10, 2022
This is generally the result of the way iMessage supports multiple device delivery. "Delivered" means that it was delivered to at least one device on the account. It does not mean it was delivered to the device in the hand of the person who owns the account. If you happen to have an iDevice logged into the account, such as an old iPad, sitting at home on the wifi, and you are someplace with spotty data, iMessage can (and sometimes will exclusively) deliver your messages to the available device rather than the device you'd hope for.
posted by jgreco at 1:42 AM on May 10, 2022
Suppose you're in a foreign country with really expensive data costs, so you've got data turned off. You want to send a text to a friend who also has an iPhone. You can't.I'm not sure if this was fixed or you were in a special-case situation, but I just tested this (turned off WiFi and Cellular Data, then texted a friend that I've only ever iMessaged with before) and it worked the way you'd want it to; Messages sent a standard (green bubble) SMS text that he received immediately.
I could speculate you ran into some bug where Messages had previously been sending iMessages "to" that person's email address / AppleID as their 'identifier' rather than their cell number, and there was some fuckery that persisted this association in Messages even after you deleted their card from Contacts. But anyways FWIW this shouldn't be the common case luckily.
posted by churl at 3:50 PM on September 2, 2022 [1 favorite]
This thread is closed to new comments.
posted by slkinsey at 6:27 AM on May 8, 2022