<?xml version='1.0'?>

<reference anchor='RFC2018'>

<front>
<title abbrev='TCP Selective Acknowledgement Options'>TCP Selective Acknowledgment Options</title>
<author initials='M.' surname='Mathis' fullname='Matt Mathis'>
<organization>Pittsburgh Supercomputing Center</organization>
<address>
<postal>
<street>4400 Fifth Ave</street>
<street>Pittsburgh</street>
<street>PA 15213</street></postal>
<email>mathis@psc.edu</email></address></author>
<author initials='J.' surname='Mahdavi' fullname='Jamshid Mahdavi'>
<organization>Pittsburgh Supercomputing Center</organization>
<address>
<postal>
<street>4400 Fifth Ave</street>
<street>Pittsburgh</street>
<street>PA 15213</street></postal>
<email>mahdavi@psc.edu</email></address></author>
<author initials='S.' surname='Floyd' fullname='Sally Floyd'>
<organization>Lawrence Berkeley National Laboratory</organization>
<address>
<postal>
<street>One Cyclotron Road</street>
<street>Berkeley</street>
<street>CA 94720</street></postal>
<email>floyd@ee.lbl.gov</email></address></author>
<author initials='A.' surname='Romanow' fullname='Allyn Romanow'>
<organization>Sun Microsystems, Inc.</organization>
<address>
<postal>
<street>2550 Garcia Ave.</street>
<street>MPK17-202</street>
<street>Mountain View</street>
<street>CA 94043</street></postal>
<email>allyn@eng.sun.com</email></address></author>
<date month='October' year='1996' />
<area>Transport</area>
<keyword>TCP</keyword>
<keyword>acknowledgement</keyword>
<keyword>transmission control protocol</keyword>
<abstract>
<t>
   TCP may experience poor performance when multiple packets are lost
   from one window of data.   With the limited information available
   from cumulative acknowledgments, a TCP sender can only learn about a
   single lost packet per round trip time.  An aggressive sender could
   choose to retransmit packets early, but such retransmitted segments
   may have already been successfully received.
</t>
<t>
   A Selective Acknowledgment (SACK) mechanism, combined with a
   selective repeat retransmission policy, can help to overcome these
   limitations.  The receiving TCP sends back SACK packets to the sender
   informing the sender of data that has been received. The sender can
   then retransmit only the missing data segments.
</t>
<t>
   This memo proposes an implementation of SACK and discusses its
   performance and related issues.
</t></abstract></front>

<seriesInfo name='RFC' value='2018' />
<format type='HTML' octets='43791' target='http://xml.resource.org/public/rfc/html/rfc2018.html' />
<format type='XML' octets='30132' target='http://xml.resource.org/public/rfc/xml/rfc2018.xml' />
</reference>
