TCP Fast Open
draft-ietf-tcpm-fastopen-07

The information below is for an old version of the document
Document Type Active Internet-Draft (tcpm WG)
Last updated 2014-02-14
Replaces draft-cheng-tcpm-fastopen
Stream IETF
Intended RFC status Experimental
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Stream WG state Waiting for WG Chair Go-Ahead
Revised I-D Needed - Issue raised by WGLC
Document shepherd Michael Scharf
IESG IESG state AD is watching
Telechat date
Responsible AD Martin Stiemerling
Send notices to tcpm-chairs@tools.ietf.org, draft-ietf-tcpm-fastopen@tools.ietf.org
Internet Draft                                                  Y. Cheng
draft-ietf-tcpm-fastopen-07.txt                                   J. Chu
Intended status: Experimental                           S. Radhakrishnan
Expiration date: August, 2014                                    A. Jain
                                                            Google, Inc.
                                                       February 14, 2014

                             TCP Fast Open

Status of this Memo

   Distribution of this memo is unlimited.

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Abstract
 

Cheng, et. al.          Expires August 18, 2014                 [Page 1]
Internet Draft               TCP Fast Open             February 14, 2014

   This document describes an experimental TCP mechanism TCP Fast Open
   (TFO). TFO allows data to be carried in the SYN and SYN-ACK packets
   and consumed by the receiving end during the initial connection
   handshake, thus saving up to one full round trip time (RTT) compared
   to the standard TCP, which requires a three-way handshake (3WHS) to
   complete before data can be exchanged. However TFO deviates from the
   standard TCP semantics the data in the SYN could be replayed to an
   application in some rare circumstances. Applications should not use
   TFO unless they can tolerate this issue detailed in the Applicability
   section.

Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].
   TFO refers to TCP Fast Open. Client refers to the TCP's active open
   side and server refers to the TCP's passive open side.

Table of Contents

   1. Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2. Data In SYN . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     2.1 Relaxing TCP Semantics on Duplicated SYNs  . . . . . . . . .  4
     2.2. SYNs with Spoofed IP Addresses  . . . . . . . . . . . . . .  4
   3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . .  5
   4. Protocol Details  . . . . . . . . . . . . . . . . . . . . . . .  7
     4.1. Fast Open Cookie  . . . . . . . . . . . . . . . . . . . . .  7
       4.1.1. TCP Options . . . . . . . . . . . . . . . . . . . . . .  7
       4.1.2. Server Cookie Handling  . . . . . . . . . . . . . . . .  8
       4.1.3. Client Cookie Handling  . . . . . . . . . . . . . . . .  9
         4.1.3.1 Client Caching Negative Responses  . . . . . . . . .  9
     4.2. Fast Open Protocol  . . . . . . . . . . . . . . . . . . . . 10
       4.2.1. Fast Open Cookie Request  . . . . . . . . . . . . . . . 10
       4.2.2. TCP Fast Open . . . . . . . . . . . . . . . . . . . . . 11
   5. Security Considerations . . . . . . . . . . . . . . . . . . . . 13
     5.1. Resource Exhaustion Attack by SYN Flood with Valid 
          Cookies . . . . . . . . . . . . . . . . . . . . . . . . . . 13
       5.1.1 Attacks from behind Shared Public IPs (NATs) . . . . . . 14
     5.2. Amplified Reflection Attack to Random Host  . . . . . . . . 15
   6. TFO's Applicability . . . . . . . . . . . . . . . . . . . . . . 16
     6.1 Duplicate Data in SYNs . . . . . . . . . . . . . . . . . . . 16
     6.2 Potential Performance Improvement  . . . . . . . . . . . . . 16
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