TCP Fast Open
draft-ietf-tcpm-fastopen-09
Internet Draft Y. Cheng
draft-ietf-tcpm-fastopen-09.txt J. Chu
Intended status: Experimental S. Radhakrishnan
Expiration date: January, 2015 A. Jain
Google, Inc.
June 30, 2014
TCP Fast Open
Abstract
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 since 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.
Status of this Memo
Distribution of this memo is unlimited.
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
Cheng, et. al. Expires January 1, 2015 [Page 1]
Internet Draft TCP Fast Open June 30, 2014
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 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 . . . . . . . . . . . . . . . . . . . . 11
4.2.1. Fast Open Cookie Request . . . . . . . . . . . . . . . 11
4.2.2. TCP Fast Open . . . . . . . . . . . . . . . . . . . . . 12
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 14
5.1. Resource Exhaustion Attack by SYN Flood with Valid
Cookies . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1.1 Attacks from behind Shared Public IPs (NATs) . . . . . . 15
5.2. Amplified Reflection Attack to Random Host . . . . . . . . 16
6. TFO's Applicability . . . . . . . . . . . . . . . . . . . . . . 17
6.1 Duplicate Data in SYNs . . . . . . . . . . . . . . . . . . . 17
6.2 Potential Performance Improvement . . . . . . . . . . . . . 17
6.3. Example: Web Clients and Servers . . . . . . . . . . . . . 18
6.3.1. HTTP Request Replay . . . . . . . . . . . . . . . . . . 18
6.3.2. Speculative Connections by the Applications . . . . . . 18
6.3.3. HTTP over TLS (HTTPS) . . . . . . . . . . . . . . . . . 18
6.3.4. Comparison with HTTP Persistent Connections . . . . . . 18
Show full document text