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by subtra3t 830 days ago
I haven't read the article yet but I think that means that UDP was used less than TCP and so routers/operating systems didn't optimize for it as much as they did for TCP. Hope this helps.
2 comments
chasd00 830 days ago
there's nothing to optimize with UDP, you put a datagram on the wire and off it goes. There's no sequence number like in TCP to re-order and construct a stream on the receiving side. There is no stream, it's UDP. You put a datagram on the wire and that's it. There no syn/ack either so no congestion control in routers, no back-off or anything.
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IgorPartola 830 days ago
Right that’s all it says on this subject. I am curious about what optimizations TCP has benefitted from that we’re not but could be applied to UDP.
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jsnell 830 days ago
For example various kinds of hardware TCP offload, like:

1. Handing the NIC a single blob of data (> MSS) in a single operation, and having the NIC do the segmentation into multiple packets.

2. Having the NIC detect multiple exactly consecutive TCP packets on the same flow, and merging them to a single receive operation.

Hardware offload is impossible to do for UDP, since neither the NIC or OS can assume anything about the payload semantics.

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