SMS very much needs servers. SMS messages go from your device to the SMSC which will store the message and try to transmit it to your phone in case your phone isn’t on or connected. In theory you could set up direct SMS messaging, but in practice there’s a layer of indirection because messages would get lost.
Since SMS can’t do anything but text, MMS is required to send images and videos, and those too travel through an MMSC so messages are available when your phone is offline (or if it doesn’t support MMS, which was something MMS had to be designed for). MMS can’t work directly between clients, it had to go through a server.
Like everything designed for carriers, MMS is a mess of moving parts and optional services that only a committee could’ve designed:
SMSCs and MMSCs may not be available over the internet, but they are very much a client-server architecture. The store-and-forward server approach is also what Signal and supposedly WhatsApp use.
SMS very much needs servers. SMS messages go from your device to the SMSC which will store the message and try to transmit it to your phone in case your phone isn’t on or connected. In theory you could set up direct SMS messaging, but in practice there’s a layer of indirection because messages would get lost.
Since SMS can’t do anything but text, MMS is required to send images and videos, and those too travel through an MMSC so messages are available when your phone is offline (or if it doesn’t support MMS, which was something MMS had to be designed for). MMS can’t work directly between clients, it had to go through a server.
Like everything designed for carriers, MMS is a mess of moving parts and optional services that only a committee could’ve designed:
SMSCs and MMSCs may not be available over the internet, but they are very much a client-server architecture. The store-and-forward server approach is also what Signal and supposedly WhatsApp use.