

UDT: Breaking the data transfer bottleneck - beagle3
http://udt.sourceforge.net/

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cbsmith
I have worked with UDT in the past. It certainly had its advantages though
wasn't always as robust as I'd like it to be. I hadn't noticed much activity
with it the last few years though. What's with the current interest?

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wmf
It was mentioned in the HPN-SSH thread:
[https://news.ycombinator.com/item?id=8329507#up_8330376](https://news.ycombinator.com/item?id=8329507#up_8330376)

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nkcpiytdhauwuhc
What's the tradeoff you make when using UDT over TCP?

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suprjami
Ugh, I am so sick of people implementing "reliable" transport on top of UDP.

If you need reliability, use TCP or SCTP. You do not know more than 25 years
of industry experience developing and implementing transport protocols.

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mcpherrinm
Both TCP and SCTP are in-order, which is what you frequently want but not
always. We don't have a good, reliable messaging protocol that allows out of
order messages, which can lead to increased latency that isn't necessary for
some use cases.

This can cause much larger latencies for messages that have arrived but aren't
delivered to the application because a previous packet was dropped and is
awaiting retransmission

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teddyh
Message ordering is _optional_ in SCTP¹.

①
[http://tools.ietf.org/html/rfc4960#section-6.6](http://tools.ietf.org/html/rfc4960#section-6.6)

