[e2e] tcp retransmission packet size.

[Bob Braden]

  *> From end2end-interest-admin at postel.org  Mon Nov 26 14:01:20 2001
  *> From: Tianbo Kuang <kuang at cpsc.ucalgary.ca>
  *> X-Accept-Language: en
  *> MIME-Version: 1.0
  *> To: end2end-interest at postel.org
  *> Content-Transfer-Encoding: 7bit
  *> Subject: [e2e] tcp retransmission packet size.
  *> X-BeenThere: end2end-interest at postel.org
  *> X-Mailman-Version: 2.0.1
  *> List-Help: <mailto:end2end-interest-request at postel.org?subject=help>
  *> List-Archive: <http://www.postel.org/pipermail/end2end-interest/>
  *> Date: Mon, 26 Nov 2001 14:56:41 -0700
  *> 
  *> Hi,
  *> 
  *> I noticed in a captured trace that a TCP sender actually retransmitted a
  *> bigger packet than the orignal one (after the ACK was dropped in the
  *> network). My question is,
  *> (1) Is this allowed by specification?

Absolutely.  In fact, it was a feature, intended especially for
character-mode terminal emulation.  The bytes from the user dribble
into TCP, and it packages and sends them as rapidly as it can.

  *> (2) If so, that means that a TCP receiver will always have to use the
  *> duplicated packet as the useful data as it contains more information. Is
  *> that true in the implementation?

It should just drop out of the reassembly process.

Bob Braden.

  *> 
  *> Thanks,
  *> 
  *> --Tianbo
  *>