Re: R: Kernel bug handling TCP_RTO_MAX?

From: Andrew McGregor (
Date: Fri Dec 13 2002 - 17:25:28 EST

--On Friday, December 13, 2002 10:07:01 -0800 Nivedita Singhvi
<> wrote:

> Andrew McGregor wrote:
>> In a closed network, why not have SOCK_STREAM map to something faster
>> than TCP anyway? That is, if I connect(address matching localnet),
>> SOCK_STREAM maps to (eg) SCTP. That would be a far more dramatic
>> performance hack!
>> Andrew
> Not that simple. SCTP (if that is what Matti was referring to) is
> a SOCK_STREAM socket, with a protocol of IPPROTO_SCTP. I'm just
> getting done implementing a testsuite against the SCTP API.
> i.e. You have to know you want an SCTP socket at the time you
> open the socket. You certainly have no idea whether youre on
> a closed network or not, for that matter, the app may want to talk
> on multiple interfaces etc. (Most hosts will have one interface
> on a public net)..

Things are never that simple. But I was basically talking about a local
policy to change the (semantics of the) API in certain cases. It's
probably a bad idea and would cause all kinds of breakage, but it is
interesting to think about.

> Currently, Linux SCTP doesn't yet support TCP style i.e SOCK_STREAM
> sockets, we only do udp-style sockets (SOCK_SEQPACKET). We will be
> putting in SOCK_STREAM support next, but understand that performance
> is not something that has been addressed yet, and a performant SCTP
> is still some ways away (though I'm sure Jon and Sridhar will be
> working their tails off to do so ;)).

I wasn't aware of the current status. Ok, that's just where it's at.

> But dont expect SCTP to be the surreptitious underlying layer
> carrying TCP traffic, if thats an expectation that anyone has :)

That's my particular kind of crazy idea.

> Solving this problem without application involvement is a
> more limited scenario..


> thanks,
> Nivedita

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