[e2e] a new IRTF group on Transport Models

Sally Floyd floyd at icir.org
Thu Jun 2 14:33:00 PDT 2005


Lloyd -

>But the drops of interest measured are presumably segment drops, or
>even segments-with-piggybacked acks drops, while drops of pure acks
>(which are logically also packet drops) are usually neglected.
>
>(And congestion/queue overflow/policy drops in routers are distinct
>from discards due to detected L2/L3 checksum errors.)
>
>Gah, semantics.

Oh dear, and I wasn't even thinking about acks vs. data packets,
or congestion- vs. corruption-related drops, when I wrote the earlier
email.  (Though I am very much interested in drop rates for pure
ack packets, as it has a big influence on the burstiness of the
data packets subsequently transmitted in the other direction.)

I was thinking about fragmentation, where a "segment" in TCP
might correspond to several "packets" on the wire.  Also resulting
in a difference between packet drop rates on-the-wire and segment
drop rates seen by the TCP sender.

Ah, semantics...

- Sally


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