[e2e] bytes vs packets
fernando at gont.com.ar
Mon Jul 28 13:27:31 PDT 2003
In the TCP section of David Clark's "The Design Philosophy of the DARPA
Internet Protocols", he mentions three reasons for TCP acknowledging bytes
rather than packets:
(1) Permit the insertion of control information into the sequence space of
the bytes, so that control as well as data could be acknowledged.
(2) Permit a TCP packet to be broken up into smaller packets if necessary
in order to fit through a net with a small packet size.
(3) Permit a number of small packets to be gathered together into one
larger packet in the sending host if retransmission of data was necessary.
When he discusses the first reason (1), he states: "That use of the
sequence space was dropped, in favor of ad hoc techniques for dealing with
each control message."
Why does he say "it was dropped"? Control information (SYNs, FINs) *is*
still included in the sequence space. Or does he refer to some other
control information? If so, which one?
While discussing the third reason (3), he states "It was not clear if this
advantage would be important; it turned out to be critical."
Wasn't any sending-side solution (such as Nagle's algorithm) considered at
e-mail: fernando at gont.com.ar || fgont at acm.org
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