[ih] When was Go Back N adopted by TCP

[Detlef Bosau]

Am 19.05.2014 17:02, schrieb Craig Partridge:
> Hi Detlef:
>
> I don't keep the 4.3bsd code around anymore, but here's my recollection
> of what the code did.
>
> 4.3BSD had one round-trip timeout (RTO) counter per TCP connection.

That's the way I find it in the NS2.
>
> On round-trip timeout, send 1MSS of data starting at the lowest outstanding
> sequence number.

Which is not yet GBN in its "pure" form, but actually it is, because
CWND is increased with every new ack. And when you call "send_much" when
a new ack arrives (I had a glance at the BSD code myself some years ago,
the routines are named equally there, as far as I've seen, the ns2 code
and the BSD code are extremely similar) the behaviour resembles GBN very
much.
>   Set the RTO counter to the next increment.
>
> Once an ack is received, update the sequence numbers and begin slow start
> again.
>
> What I don't remember is whether 4.3bsd kept track of multiple outstanding
> losses and fixed all of them before slow start or not.

OMG. ;-) Who else should remember this, if not Van himself our you?

However, first of all I have to thank for all the answers here.

Detlef

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