It's time to replace TCP in the datacenter (2023)

Websockets is a layer on top of TCP/IP.

Yes, I know that WebSockets layer over TCP/IP. But that both misses the point and is part of the point. The reason that I ask is that WebSockets seem to almost always be used in the context of web applications. TCP/IP still seems to dominate control communications between hardware. But why not WebSockets? Almost everyone ends up building a message framing protocol on top of TCP/IP, so why not just use WebSockets which has bi-directional message framing built-in? I'm just not seeing why WebSockets aren't as ubiquitous as TCP/IP and only seem to be relegated to web applications.

WebSocket is fairly inefficient protocol. and it needs to deal with the upgrade from HTTP. and you still need to implement you app specific protocol. This is adding complexity without additional benefit

It make sense only if you have an websocket based stack and don't want to maintain a second protocol.

Interesting point. For example, Web apps cannot speak BitTorrent (because Web apps are not allowed to use TCP) but they can speak WebTorrent over WebRTC and native apps can also speak WebTorrent. So in some sense a protocol that runs over WebSockets/WebRTC is superior because Web apps and native apps can speak it.

There isn't much of a difference between a router between two machines physically next to each other and a router in Kansas connecting a machine in California with a machine in Miami. The packets of data are wrapped with an address of where they are going in the header.

WebSockets are long lived socket connection designed specifically for use on the 'web'. TCP is data sent wrapped in packets that is ordered and guaranteed delivery. This causes a massive overhead cost. This is different from UDP which doesn't guarantee order and delivery. However, a packet sent over UDP might arrive tomorrow after it goes around the world a few times.

With fetch() or XMLHttpRequest, the client has to use energy and time to open a new HTTP connection while a WebSocket opens a long lived connection. When sending lots of bi directional messages it makes sense to have a WebSocket. However, a simple fetch() request is easier to develop. A developer needs to good reason to use the more complicated WebSocket.

Regardless, they both send messages using TCP which ensures the order of packets and guaranteed delivery which features have a lot to do with why TCP is the first choice.

There is UDP which is used by WebRTC which is good for information like voice or video which can have missing and unordered packets occasionally.

If two different processes on the same machine want to communicate, they can use a Unix socket. A Unix socket creates a special file (socket file) in the filesystem, which both processes can use to establish a connection and exchange data directly through the socket, not by reading and writing to the file itself. But the Unix Socket doesn't have to deal with routing data packets.

(ChatGPT says "Overall, you have a solid grasp of the concepts, and your statements are largely accurate with some minor clarifications needed.")

You can easily build a JSON based RPC protocol in a few minutes using WebSockets and be done. With raw TCP you're going to be spending a week doing something millions of other developers have done again and again in your own custom bespoke way that nobody else will understand.

Your second point is very dismissive. You're inserting random application requirements that the vast majority of application developers don't care about and then you claim that only in this situation do WebSockets make sense when in reality the vast majority of developers only use WebSockets and your suggestion involves the second unwanted protocol (e.g. the horror that is protobuffers and gRPC).

> WebSocket is fairly inefficient protocol

In what way?

> This is adding complexity without additional benefit

I'm not sure that's a given. For example, WebSockets actually implement a message protocol. You have gauarantees that you sent or received the whole message. That may not be the case for TCP/IP, which is a byte streaming protocol.