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Quick-Start for TCP and IP
RFC 4782

Approval Announcement

Draft of message to be sent after approval:

From: The IESG <iesg-secretary@ietf.org>
To: IETF-Announce <ietf-announce@ietf.org>
Cc: Internet Architecture Board <iab@iab.org>,
    RFC Editor <rfc-editor@rfc-editor.org>
Subject: Document Action: 'Quick-Start for TCP and IP' to 
         Experimental RFC 

The IESG has approved the following document:

- 'Quick-Start for TCP and IP '
   <draft-ietf-tsvwg-quickstart-08.txt> as an Experimental RFC

This document is the product of the Transport Area Working Group. 

The IESG contact persons are Lars Eggert and Magnus Westerlund.

A URL of this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-tsvwg-quickstart-08.txt
Technical Summary
 
This document defines an optional means of accelerating normal slow
start(ish) transfer rate procedures of a transport protocol into the
(potentially many) Mbps flows have access to. The Quickstart sending
rate is requested, and never mandatory. The fall back is to normal
slow start(ish) ramp ups, requiring many RTTs, in bandwidth utilized.

This document outlines how Quickstart is used in TCP, but the mechanism
is not specific to any transport protocol - with a lot of discussion on
how it affects UDP (VoIP) flows. This document limits flows that can
use Quickstart to at least 80kbps or higher. There are pitfalls and
problems to be explored with this mechanism (most thought of are
discussed extensively), which is why this is Experimental, instead of
Standards Track. Rough running code of this mechanism already exists in
several places, with generally positive results, even for VoIP.

 
Working Group Summary
 
There is strong consensus in the WG to publish this document. It has
been reviewed by several people in the WG last call. Comments raised
have been addressed.

 
Protocol Quality
 
This document is making an experimental, optional extension to
transport protocol initial transfer rates. TCP is highlighted in
the document, though other transport protocols are able to use this
mechanism. It is not making a new protocol.

This document has been well reviewed in the WG and comments raised
have been addressed promptly.

James Polk (jmpolk@cisco.com) has acted as Document Shepherd.

Lars Eggert (lars.eggert@netlab.nec.de) has reviewed this document for
the IESG.


Note to RFC Editor
 
Add the following text as the first item in Section 9.2:

    The cost of having a Quick-Start request packet dropped:
    Measurement studies cited earlier [MAF04] suggest that on a wide
    range of paths in the Internet, TCP SYN packets containing unknown
    IP options will be dropped.  Thus, for the sender one risk in using
    Quick-Start is that the packet carrying the Quick-Start Request
    could be dropped in the network.  It is particularly costly to the
    sender when a TCP SYN packet is dropped, because in this case the
    sender should wait for an RTO of three seconds before re-sending the
    SYN packet, as specified in Section 4.7.2.