Re: /dev/random probs in 2.4test(12-pre3)

From: Andrew Morton (andrewm@uow.edu.au)
Date: Sun Dec 03 2000 - 07:20:36 EST


Alexander Viro wrote:
>
> Erm... Not that ignoring the return values was a bright idea, but the
> lack of reliable ordered datagram protocol in IP family is not a good
> thing. It can be implemented over TCP, but it's a big overkill. IL is a
> nice thing to have...

Pet peeve? There are about five "reliable UDPs" floating
around. Take a look at

        http://www.faqs.org/rfcs/rfc2960.html

SCTP is mainly designed as a way of transporting telephony signalling
information across IP. But it is now a quite general purpose protocol.

Culturally, this is "Telephony industry comes to IP. Telephony
industry is appalled. IP industry gets a clue".

SCTP provides the reliable delivery of messages to which you refer.
It's slightly more efficient than TCP for a given set of network
characteristics - there's no statement about implementation
efficiency here. No head-of-line blocking issues.

One very interesting part of SCTP is that transport endpoints are
explicitly set up between *hosts*, not between IP addresses. The
protocol is designed around multihomed hosts.

I don't know if anyone has looked into mapping SCTP capabilities onto
the BSD socket API. It may be hard.

The reference implementation is for userland Linux. It's at
ftp://standards.nortelnetworks.com/sigtran/

A good kernel-mode implementation of SCTP for Linux would be
a very big project. But also a very big contribution.
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