Re: SCTP, DCCP and MobileIP

[David Laight <david%l8s.co.uk@localhost>]

On Mon, Mar 10, 2014 at 04:21:16PM -0400, Mouse wrote:
> > sctp isn't really that nice a protocol.  [...]
> 
> Yeah, I read the spec.
> 
> > You'd probably get better throughput by using multiple TCP
> > connections and relying on the application level retries to recover
> > from packets that are lost when a connection fails.
> 
> ...plus UDP for a few other things (unreliable packets and heartbeats
> come to mind).  You'd also have to rework the userland layers to impose
> their own packetization on TCP, that being another thing SCTP offers.
> 
> That is certainly arguable, but it wouldn't then interoperate with the
> existing SCTP-using code (currently running on Linux).

I'm not sure which protocol you need to carry, but the standard sigtran
encoding (for about everythng except m2ua) contains a record length in
the userdata - so it runs fine over TCP provided you debatch the rx data.
The big advantage of TCP is that it is far easier to get multuple
user packets into a single ethernet frame.
That is almost impossible with sctp - especially if you disable Nagle.

The sctp protocol RFC does contain a whole load of stuff that isn't
directly related to the protocol.
All the stuff about handling multiple connections through a single socket
and simulating connectionless traffic is all local and hidden from the
remote system - it is all solving an orthogonal problem.

        David

-- 
David Laight: david%l8s.co.uk@localhost