A Technology Preview of Nginx Support for QUIC and HTTP/3

Re:A Technology Preview of Nginx Support for QUIC and HTTP/3 by dehrmann on Saturday June 20, 2020 @07:11PM (#23588225)

I'm not sure if forward error correction works with UDP. UDP has a checksum field that's optional in IPv4, mandatory in IPv6 (why IPvAnything dictates anything in the transport layer is beyond me). Assuming you treat the checksum as absent and set it to zeros, it could still get added at any hop, and if that gets corrupted, the packet would be dropped.

If routers either ignore the checksum or never add it in, it could work.

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Re:A Technology Preview of Nginx Support for QUIC and HTTP/3 by p1mrx on Saturday June 20, 2020 @07:56PM (#23588474)

UDP's checksum depends on information from the IP header, for both IPv4 and IPv6: https://en.wikipedia.org/wiki/User_Datagram_Protocol#Checksu...

Omitting the UDP/IPv4 checksum is permitted because the IPv4 header has its own redundant checksum, but omitting the UDP/IPv6 checksum would leave the IPv6 header with no checksum at all, which is why that's not permitted.

https://en.wikipedia.org/wiki/UDP-Lite lets you checksum the UDP/IP header plus an arbitrary (possibly zero-length) prefix of the payload, but I'm not sure if people actually use that.

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Re:A Technology Preview of Nginx Support for QUIC and HTTP/3 by comex on Saturday June 20, 2020 @08:49PM (#23588724)

I believe the "errors" in this context are generally not actual corrupted packets, which are rare, but dropped packets seen in the context of a larger data transmission.

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