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I think both protocol upgrades are misunderstood: HTTP/2 Besides the performance improvements brought in HTTP/2 via compression of headers and ability to mult

by pa7x1 6y ago

I think both protocol upgrades are misunderstood: HTTP/2 Besides the performance improvements brought in HTTP/2 via compression of headers and ability to multiplex streams it also enables full-duplex communication (à la WebSockets) [1]. This is used for example in gRPC, making the protocol far more versatile than given credit. [1] No, I'm not talking about Server Push. HTTP/3 HTTP/3 should bring benefits in wireless connections where TCP disconnections are frequent. QUIC handles connection identification so frequent TCP disconnects or even changing IPs would impact much less an HTTP/3 connection. I don't have the benchmarks but I would expect HTTP/3 to shine in this scenario which is bound to be more and more relevant with mobile devices, 5G, etc... In ideal, wired network, conditions HTTP/3 is probably not going to bring any improvement maybe even worse performance considering how much effort must have gone to optimizing TCP. For me, both upgrades have a raison d'être but that doesn't mean that they displace HTTP/1.1 of all use cases. If you don't care about the performance improvements or need full-duplex no need to use HTTP/2, if you are not targeting mobile networks no need for HTTP/3. Luckily protocol negotiation should be quite seamless.

erinnh 6y ago
As a general question: why I do have to configure any nginx server that I want to use websockets on to specifically use http 1.1 if 2.0 also has support for them?
- chrismorgan 6y ago
  WebSockets was defined in a way that was incompatible with HTTP/2. RFC 8441 defines a way of reconciling the two, and explains the nature of the problem in its introduction: https://tools.ietf.org/html/rfc8441#section-1 https://tools.ietf.org/html/rfc8441#section-1. But I don’t believe any browsers has landed support for this yet. (In Chrome it’s been behind a flag for 2½ years with apparently no changes for the last two years. No idea what the hold-up is. https://www.chromestatus.com/feature/6251293127475200 https://www.chromestatus.com/feature/6251293127475200.)
- pa7x1 6y ago
  To add a bit more information to what the sibling post provides. The original WebSocket handshake is done over HTTP/1.1, there is an RFC specifying how to perform the negotiation also over HTTP/2 connection but its support lacking. On top of that, HTTP/2 itself can do full-duplex communication so it can be used as a replacement of WebSocket, no negotiation or protocol upgrade involved. This capability is rarely used though but is, for example, leveraged by gRPC which is able to do bidirectional streaming [1]. [1] https://grpc.io/docs/what-is-grpc/core-concepts/ https://grpc.io/docs/what-is-grpc/core-concepts/

by pa7x1 6y ago

erinnh 6y ago

As a general question: why I do have to configure any nginx server that I want to use websockets on to specifically use http 1.1 if 2.0 also has support for them?

chrismorgan 6y ago
WebSockets was defined in a way that was incompatible with HTTP/2. RFC 8441 defines a way of reconciling the two, and explains the nature of the problem in its introduction: https://tools.ietf.org/html/rfc8441#section-1 https://tools.ietf.org/html/rfc8441#section-1. But I don’t believe any browsers has landed support for this yet. (In Chrome it’s been behind a flag for 2½ years with apparently no changes for the last two years. No idea what the hold-up is. https://www.chromestatus.com/feature/6251293127475200 https://www.chromestatus.com/feature/6251293127475200.)
pa7x1 6y ago
To add a bit more information to what the sibling post provides. The original WebSocket handshake is done over HTTP/1.1, there is an RFC specifying how to perform the negotiation also over HTTP/2 connection but its support lacking. On top of that, HTTP/2 itself can do full-duplex communication so it can be used as a replacement of WebSocket, no negotiation or protocol upgrade involved. This capability is rarely used though but is, for example, leveraged by gRPC which is able to do bidirectional streaming [1]. [1] https://grpc.io/docs/what-is-grpc/core-concepts/ https://grpc.io/docs/what-is-grpc/core-concepts/