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[tcpm] RFC 2883 (D-SACK), Section 5.1 Replication by the network

Alexander Zimmermann <Alexander.Zimmermann@nets.rwth-aachen.de> Thu, 06 November 2008 08:26 UTC

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Date: Thu, 06 Nov 2008 09:25:55 +0100
From: Alexander Zimmermann <Alexander.Zimmermann@nets.rwth-aachen.de>
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Subject: [tcpm] RFC 2883 (D-SACK), Section 5.1 Replication by the network
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Hi folks,

RFC 2883, Section 5.1 states that without D-SACK a TCP sender would
not know that a packet had been replicated in the network if the last  
ACK
was piggybacked on a data packet.

According 2581(bis) a TCP receiver should send immediately an DUPACK
when an out-of-order segment arrives. Furthermore, 2581bis says that a
DUPACK carries no data.

So, according to the DUPACK definition of 2581bis it seems to me that we
have no problem to detect a packet replication in case D-SACK is not
present. Right?

Alex

//
// Dipl.-Inform. Alexander Zimmermann
// Department of Computer Science, Informatik 4
// RWTH Aachen University
// Ahornstr. 55, 52056 Aachen, Germany
// phone: (49-241) 80-21422, fax: (49-241) 80-22220
// email: zimmermann@cs.rwth-aachen.de
// web: http://www.umic-mesh.net
//


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