draft-ietf-tcpm-tcp-roadmap-00.txt   draft-ietf-tcpm-tcp-roadmap-01.txt 
Network Working Group M. Duke Network Working Group M. Duke
Internet-Draft Boeing Phantom Works Internet-Draft Boeing Phantom Works
Expires: April 8, 2005 R. Braden Expires: July 21, 2005 R. Braden
USC Information Sciences Institute USC Information Sciences Institute
W. Eddy W. Eddy
NASA GRC/Verizon FNS NASA GRC/Verizon FNS
E. Blanton E. Blanton
Purdue University Purdue University
October 8, 2004 January 20, 2005
A Roadmap for TCP Specification Documents A Roadmap for TCP Specification Documents
draft-ietf-tcpm-tcp-roadmap-00 draft-ietf-tcpm-tcp-roadmap-01
Status of this Memo Status of this Memo
This document is an Internet-Draft and is subject to all provisions This document is an Internet-Draft and is subject to all provisions
of section 3 of RFC 3667. By submitting this Internet-Draft, each of section 3 of RFC 3667. By submitting this Internet-Draft, each
author represents that any applicable patent or other IPR claims of author represents that any applicable patent or other IPR claims of
which he or she is aware have been or will be disclosed, and any of which he or she is aware have been or will be disclosed, and any of
which he or she become aware will be disclosed, in accordance with which he or she become aware will be disclosed, in accordance with
RFC 3668. RFC 3668.
skipping to change at page 1, line 41 skipping to change at page 1, line 41
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on April 8, 2005. This Internet-Draft will expire on July 21, 2005.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2004). Copyright (C) The Internet Society (2005).
Abstract Abstract
This document contains a "roadmap" to the Requests for Comments (RFC) This document contains a "roadmap" to the Requests for Comments (RFC)
documents relating to the Internet's Transmission Control Protocol documents relating to the Internet's Transmission Control Protocol
(TCP). This roadmap provides a brief summary of the documents (TCP). This roadmap provides a brief summary of the documents
defining TCP and various TCP extensions that have accumulated in the defining TCP and various TCP extensions that have accumulated in the
RFC series. This serves as a rough guide and quick reference for RFC series. This serves as a guide and quick reference for both TCP
both TCP implementers and other parties that need help consuming the implementers and other parties who desire information contained in
vast cornucopia of TCP-related RFCs. the TCP-related RFCs.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Basic Functionality . . . . . . . . . . . . . . . . . . . . . 5
3. Standard Enhancements . . . . . . . . . . . . . . . . . . . . 7
3.1 Congestion Control and Loss Recovery Extensions . . . . . 7
3.2 SACK-based Loss Recovery and Congestion Control . . . . . 9
3.3 Dealing with Forged Segments . . . . . . . . . . . . . . . 9
4. Experimental Extensions . . . . . . . . . . . . . . . . . . . 11
5. Historic Extensions . . . . . . . . . . . . . . . . . . . . . 13
6. Support Documents . . . . . . . . . . . . . . . . . . . . . . 15
6.1 Foundational Works . . . . . . . . . . . . . . . . . . . . 15
6.2 Difficult Network Environments . . . . . . . . . . . . . . 16
6.3 Implementation Advice . . . . . . . . . . . . . . . . . . 18
6.4 Management Information Bases . . . . . . . . . . . . . . . 19
6.5 Tools and Tutorials . . . . . . . . . . . . . . . . . . . 20
6.6 Case Studies . . . . . . . . . . . . . . . . . . . . . . . 21
7. Security Considerations . . . . . . . . . . . . . . . . . . . 23
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25
9.1 Basic Functionality . . . . . . . . . . . . . . . . . . . 25
9.2 Standard Enhancements . . . . . . . . . . . . . . . . . . 25
9.3 Experimental Extensions . . . . . . . . . . . . . . . . . 26
9.4 Historic Extensions . . . . . . . . . . . . . . . . . . . 27
9.5 Support Documents . . . . . . . . . . . . . . . . . . . . 27
9.6 Informative References Outside the RFC Series . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 30
Intellectual Property and Copyright Statements . . . . . . . . 32
1. Introduction 1. Introduction
One critical part of an Internet host's software is a correct and A correct and efficient implementation of the Transmission Control
efficient implementation of the Transmission Control Protocol (TCP) Protocol (TCP) [RFC0793] is a critical part of the software of most
[RFC0793]. As TCP has evolved over the years, many distinct Internet hosts. As TCP has evolved over the years, many distinct
documents have become part of the accepted standard for TCP. At the documents have become part of the accepted standard for TCP. At the
same time, a large number of more experimental modifications to TCP same time, a large number of more experimental modifications to TCP
have been published in the RFC series. have also been published in the RFC series, along with informational
notes, case studies, and other advice.
As an introduction to newcomers and an attempt to organize the As an introduction to newcomers and an attempt to organize the
plethora of information for old hands, this document contains a plethora of information for old hands, this document contains a
"roadmap" to the TCP-related RFCs. It provides a brief summary of "roadmap" to the TCP-related RFCs. It provides a brief summary of
the relevant RFC documents that define TCP. This can give rough the RFC documents that define TCP. This should provide guidance to
guidance to implementers on the relevance and significance of various implementers on the relevance and significance of the standards track
standards track extensions, informational notes, and best current extensions, informational notes, and best current practices that
practices relate to TCP.
This roadmap includes a brief description of the contents of each
TCP-related RFC. In some cases, we simply supply the abstract or a
key summary sentence from the text as a terse description. In
addition, a letter code after each RFC number indicates its category
in the RFC series:
This roadmap includes a brief description of the contents and
relevance of each TCP-related RFC. In some cases, we simply supply
the abstract or some key summary sentence from the text as a terse
description. In addition, a letter code after each RFC number
indicates its category in the RFC series:
S - Standards Track (Proposed Standard, Draft Standard, or S - Standards Track (Proposed Standard, Draft Standard, or
Standard) Standard)
E - Experimental E - Experimental
B - Best Current Practice B - Best Current Practice
I - Informational I - Informational
Note that the category of each RFC does not necessarily reflect its Note that the category of an RFC does not necessarily reflect its
current relevance. For instance, RFC 2581 is nearly universally current relevance. For instance, RFC 2581 is nearly universally
deployed although it is only a "Proposed Standard". Similarly, some deployed although it is only a Proposed Standard. Similarly, some
"Informational" RFCs actually contain technical proposals for Informational RFCs contain significant technical proposals for
changing TCP. changing TCP.
Section 2 lists the RFCs that form the core TCP specification. This roadmap is divided into four main sections. Section 2 lists the
Section 3 lists some RFCs that provide suggestions for implementers RFCs that describe absolutely required TCP behaviors for proper
or describe best current practices concerning issues raised by functioning and interoperability. Further RFCs that describe
particular network environments. Section 4 lists RFCs that are strongly encouraged, but not essential, behaviors are listed in
experimental and may one day become standards, Section 5 lists some Section 3. Experimental extensions which are not yet standard
deprecated extensions, Section 6 contains case studies and analysis, practices, but potentially could be in the future, are described in
and Section 7 provides tips and tools for implementers. Within each Section 4.
section, RFCs are listed in chronological order.
When this document describes a features as "available in modern
operating systems", we mean that the feature is at least present in
widely deployed versions of today's Linux, BSD-derived, and Windows
operating systems. Many other specific operating systems are in use
on the Internet, and feature support varies widely both among them
and among specific versions of even the few operating systems in the
above list. However, if we say a feature is found in "modern
operating systems", the reader may fairly safely bet that it can at
least be found in most presently maintained commercial Unix flavors,
Cisco IOS versions, and various real-time and embedded kernels that
offer TCP support.
2. Core Specification
A small number of documents compose the core specification of TCP. The reader probably notices that these three sections are broadly
These can be grouped into the base documents, describing things like equivalent to MUST/SHOULD/MAY specifications, and while the authors
the header format and state machine operation, documents describing support this intuition, this document is merely descriptive; it does
congestion control behaviors, and documents that detail SACK use for not represent a binding standards track position. An individual
efficient loss recovery. At this time every conformant TCP implementor still needs to examine the standards documents themselves
implementation should implement: to evaluate specific requirement levels.
Base protocol: RFC 793, as extended and clarified by RFC 1122, RFC A small number of older experimental extensions which have not caught
1323, RFC 2873, and RFC 2988. These documents are described in on are noted in Section 5. Many other supporting documents that are
Section 2.1 relevant to the development, implementation, and deployment of TCP
Congestion control: RFC 2581, RFC 3042, RFC 3168, RFC 3390, and are described in Section 6. Within each section, RFCs are listed in
RFC 3782. Section 2.2 discusses these RFCs. chronological order.
SACK: RFC 2018, RFC 2883, and RFC 3517 are noted in Section 2.3
In addition to these core documents, there are a number of standards 2. Basic Functionality
track documents that describe the TCP MIB statistics that are
required to be kept. These documents are listed in Section 2.4 and
their history is sketched, as a somewhat complex relationship exists
between them.
2.1 Base Protocol A small number of documents compose the core specification of TCP.
These define the required basic functionalities of TCP's header
parsing, state machine, congestion control, and retransmission
timeout computation. These base specifications must be correctly
followed for interoperability.
RFC 0793 S: "Transmission Control Protocol", STD 7 (Sep 81) RFC 793 S: "Transmission Control Protocol", STD 7 (September 1981)
This is the fundamental TCP specification document. Written by This is the fundamental TCP specification document [RFC0793].
Jon Postel as part of the Internet protocol suite's core, it Written by Jon Postel as part of the Internet protocol suite's
describes the TCP packet format, the TCP state machine and event core, it describes the TCP packet format, the TCP state machine
processing, and TCP's semantics for data transmission, and event processing, and TCP's semantics for data transmission,
reliability, flow control, multiplexing, and acknowledgement. reliability, flow control, multiplexing, and acknowledgement.
Although the precedence and security compartment portions are
mostly irrelevant today, the majority of this document still Section 3.6 of RFC 793, describing TCP's handling of the IP
acurately describes modern TCPs. [RFC0793] precedence and security compartment, is mostly irrelevant today.
RFC 2873 changed the IP precedence handling, and the security
compartment portion of the API is no longer implemented or used.
In addition, RFC 793 did not describe any congestion control
mechanism. Otherwise, however, the majority of this document
still acurately describes modern TCPs. RFC 793 is the last of a
series of developmental TCP specifications, starting from IENs and
continuing in the RFC series.
RFC 1122 S: "Requirements for Internet Hosts - Communication Layers" RFC 1122 S: "Requirements for Internet Hosts - Communication Layers"
(Oct 89) (October 1989)
This document updates and clarifies RFC 793; fixing some This document [RFC1122] updates and clarifies RFC 793, fixing some
specification bugs and oversights. It also explains some features specification bugs and oversights. It also explains some features
such as keep-alives and Karn's and Jacobson's RTO estimation such as keep-alives and Karn's and Jacobson's RTO estimation
algorithms [karn][vj88]. ICMP interactions are mentioned and some algorithms [Karn][VJ88]. ICMP interactions are mentioned and some
tips are given for efficient implementation. RFC 1122 lists the tips are given for efficient implementation. RFC 1122 is an
various features that MUST, SHOULD, MAY, SHOULD NOT, and MUST NOT Applicability Statement, listing the various features that MUST,
be present in standards-conforming TCP implementations. [RFC1122] SHOULD, MAY, SHOULD NOT, and MUST NOT be present in
RFC 1323 S: "TCP Extensions for High Performance" (May 92) standards-conforming TCP implementations.
This document introduces window scaling, timestamps, and RFC 2147 S: "TCP and UDP over IPv6 Jumbograms" (May 1997)
protection against wrapped sequence numbers for efficient and safe
operation over paths with large bandwidth-delay products. These
are all commonly found in modern operating systems; however, they
may require manual tuning and configuration. There are some
corner cases in this specification that are still under
discussion. [RFC1323]
RFC 2873 S: "TCP Processing of the IPv4 Precendence Field" (Jun 00) IPv6's support for longer datagrams than were allowed in IPv4,
necessitated some changes to the way that TCP's MSS and Urgent
fields (both 16 bits) are treated.
This document removes from the TCP specification all processing of RFC 2460 S: "Internet Protocol, Version 6 (IPv6) Specification
the precedence bits of the TOS byte of the IP header. This (December 1998)
resolves a conflict between RFC 793 and Diff-Serv. [RFC2873]
RFC 2988 S: "Computing TCP's Retransmission Timer" (Nov 00) This document [RFC2460] makes a slight update to the way the
pseudo-header for checksum computation is derived, defining the
process for IPv6 in addition to the previous practice for IPv4.
RFC 2581 S: "TCP Congestion Control" (April 1999)
Although RFC 793 did not contain any congestion control
mechanisms, today congestion control is a required component of
TCP implementations. This document [RFC2581] defines the current
versions of Van Jacobson's congestion avoidance and control
mechanisms for TCP, based on his 1988 SIGCOMM paper [VJ88]. RFC
2001 was a conceptual precursor that was obsoleted by RFC 2581.
A number of behaviors that together comprise what the community
refers to as "Reno TCP", are described in RFC 2581. The name
"Reno" comes from the Net/2 release of the 4.3 BSD operating
system. This is generally regarded as the least common
denominator among TCP flavors currently found running on Internet
hosts. Reno TCP includes the congestion control features of slow
start, congestion avoidance, fast retransmit, and fast recovery.
RFC 2873 S: "TCP Processing of the IPv4 Precendence Field" (June
2000)
This document [RFC2873] removes from the TCP specification all
processing of the precedence bits of the TOS byte of the IP
header. This resolves a conflict over the use of these bits
between RFC 793 and Differentiated Services.
RFC 2988 S: "Computing TCP's Retransmission Timer" (November 2000)
Abstract: "This document defines the standard algorithm that Abstract: "This document defines the standard algorithm that
Transmission Control Protocol (TCP) senders are required to use to Transmission Control Protocol (TCP) senders are required to use to
compute and manage their retransmission timer. It expands on the compute and manage their retransmission timer. It expands on the
discussion in section 4.2.3.1 of RFC 1122 and upgrades the discussion in section 4.2.3.1 of RFC 1122 and upgrades the
requirement of supporting the algorithm from a SHOULD to a MUST." requirement of supporting the algorithm from a SHOULD to a MUST."
[RFC2988] [RFC2988]
2.2 Congestion Control 3. Standard Enhancements
RFC 2581 S: "TCP Congestion Control" (Apr 99)
This document defines the current versions of Van Jacobson's This section describes recommended TCP modifications that improve
congestion avoidance and control mechanisms for TCP, based on his performance and security. RFCs 1323 and 3168 represent fundamental
1988 SIGCOMM paper [vj88]. [RFC2581] changes to the protocol. RFC 1323, based on RFCs 1072 and 1185,
allows better utilization of high bandwidth-delay product paths by
providing some needed mechanisms for high-rate transfers. RFC 3168
describes a change to the Internet's architecture, where routers
signal end-hosts of growing congestion levels, and can do so before
packet losses are forced. Section 3.1 lists improvements in the
congestion control and loss recovery mechanisms specified in RFC
2581. Section 3.2 describes further refinements that make use of
selective acknowledgements. Section 3.3 deals with the problem of
preventing forged segments.
RFC 3042 S: "Enhancing TCP's Loss Recovery Using Limited Transmit" RFC 1323 S: "TCP Extensions for High Performance" (May 1992)
(Jan 01)
Abstract: "This document proposes a new Transmission Control This document [RFC1323] defines TCP extensions for window scaling,
Protocol (TCP) mechanism that can be used to more effectively timestamps, and protection against wrapped sequence numbers, for
recover lost segments when a connection's congestion window is efficient and safe operation over paths with large bandwidth-delay
small, or when a large number of segments are lost in a single products. These extensions are commonly found in currently-used
transmission window." [RFC3042] systems; however, they may require manual tuning and
configuration. Some "corner cases" in this specification are
still under discussion.
RFC 3168 S: "The Addition of Explicit Congestion Notification (ECN) RFC 3168 S: "The Addition of Explicit Congestion Notification (ECN)
to IP" (Sep 01) to IP" (September 2001)
This document defines a means of detecting congestion without This document [RFC3168] defines a means of detecting congestion
resorting to loss. Although congestion notification takes place without resorting to packet loss. Although congestion
at the IP level, support is required at the transport level to notification takes place at the IP level, ECN requires support at
echo the bits and adapt the sending rate. This document updates the transport level (e.g., in TCP) to echo the bits and adapt the
RFC 793 to define two previously-unused flag bits in the TCP sending rate. This document updates RFC 793 to define two
header. [RFC3168] previously-unused flag bits in the TCP header for ECN support.
RFC 3540 provides a supplementary (experimental) means for making
ECN use more secure, and RFC 2884 provides some sample results
from using ECN.
RFC 3390 S: "Increasing TCP'S Initial Window" (Oct 02) 3.1 Congestion Control and Loss Recovery Extensions
This document permits a TCP to use an initial window larger that Two of the most important aspects of TCP are its congestion control
one packet during in the slow-start phase, updating RFC 2581. and loss recovery features. Since TCP traditionally (in the absence
[RFC3390] of ECN) uses losses to infer congestion, there is a rather intimate
coupling between congestion control and loss recovery mechanisms.
There are several extensions to both features, and more often than
not, a particular extension applies to both. In this sub-section, we
group enhancements to either congestion control, loss recovery, or
both, which can be performed unilaterally - without negotiating
support between endpoints. In the next sub-section, we group the
extensions which specify or rely on the SACK option, whose use must
be negotiated bilaterally. TCP implementations should include the
enhancements from both sub-sections so that they can perform well
without regard to the feature sets of other hosts they connect to.
For example, if SACK use is not successfully negotiated, a TCP should
use the NewReno behavior as a fall-back.
RFC 3042 S: "Enhancing TCP's Loss Recovery Using Limited Transmit"
(January 2001)
Abstract: "This document proposes [Limited Transmit,] a new
Transmission Control Protocol (TCP) mechanism that can be used to
more effectively recover lost segments when a connection's
congestion window is small, or when a large number of segments are
lost in a single transmission window." [RFC3042]
RFC 3390 S: "Increasing TCP'S Initial Window" (October 2002)
This document [RFC3390] updates RFC 2581 to permit an initial TCP
window larger that one packet during in the slow-start phase.
RFC 3782 S: "The NewReno Modification to TCP's Fast Recovery RFC 3782 S: "The NewReno Modification to TCP's Fast Recovery
Algorithm" (Apr 04) Algorithm" (April 2004)
This document specifies a slight modification to the standard Reno This document [RFC3782] specifies a slight modification to the
fast recovery algorithm, whereby a TCP sender can use partial standard Reno fast recovery algorithm, whereby a TCP sender can
acknowledgements to make inferences determining the next segment use partial acknowledgements to make inferences determining the
to send in situations where SACK would be helpful, but isn't next segment to send in situations where SACK would be helpful,
available. [RFC3782] but isn't available.
2.3 SACK-based Loss Recovery Work in progress: The Eifel Response Algorithm for TCP (Internet
Draft name: draft-ietf-tsvwg-tcp-eifel-response)
RFC 2018 S: "TCP Selective Acknowledgement Options" (Oct 96) At the time of this writing, work on this document (from authors
Reiner Ludwig and Andrei Gurtov) had stabilized within the
Transport Area Working Group, and the document was planned to
become a Proposed Standard, pending IESG review, but was not yet a
part of the RFC series. This document describes the response
portion of the Eifel algorithm, which can be used in conjunction
with one of several methods of detecting when loss recovery has
been spuriously entered, such as the Eifel detection algorithm in
RFC 3522, the algorithm in RFC 3708, or F-RTO.
This document defines the sective acknowledgement (SACK) Abstract: "Based on an appropriate detection algorithm, the Eifel
mechanism, providing more fine-grained acknowledgement information response algorithm provides a way for a TCP sender to respond to a
than the basic cummulative acknowledgement mechanism. Exchange of detected spurious timeout. It adapts the retransmission timer to
SACK information is widely implemented in modern operating avoid further spurious timeouts, and can avoid - depending on the
systems. [RFC2018] detection algorithm - the often unnecessary go-back-N retransmits
that would otherwise be sent. In addition, the Eifel response
algorithm restores the congestion control state in such a way that
packet bursts are avoided."
3.2 SACK-based Loss Recovery and Congestion Control
The base TCP specification in RFC 793 provided only a simple
cumulative acknowledgment mechanism. However, a selective
acknowledgment (SACK) mechanism provides significant performance
improvement in the presence of packet losses, more than outweighing
the modest increase in complexity. A TCP should be expected to
implement SACK, however SACK is a negotiated option and is only used
if support is advertised by both sides of a connection.
RFC 2018 S: "TCP Selective Acknowledgement Options" (October 1996)
This document [RFC2018] defines the basic selective
acknowledgement (SACK) mechanism for TCP.
RFC 2883 S: "An Extension to the Selective Acknowledgement (SACK) RFC 2883 S: "An Extension to the Selective Acknowledgement (SACK)
Option for TCP" (Jul 00) Option for TCP" (July 2000)
This document extends RFC 2018 to cover the case of acknowledging This document [RFC2883] extends RFC 2018 to cover the case of
duplicate packets. [RFC2883] acknowledging duplicate packets.
RFC 3517 S: "A Conservative Selective Acknowledgement (SACK)-based RFC 3517 S: "A Conservative Selective Acknowledgement (SACK)-based
Loss Recovery Algorithm for TCP" (Apr 03) Loss Recovery Algorithm for TCP" (April 2003)
This document describes a TCP loss recovery algorithm which uses This document [RFC3517] describes a relatively sophisticated
available SACK information to intelligently recover when more than algorithm that a TCP sender can use for loss recovery when SACK
one segment is lost from a single flight of data. While support reports more than one segment lost from a single flight of data.
for the exchange of SACK information is widely implemented, not While support for the exchange of SACK information is widely
all implementations use an algorithm as sophisticated as that implemented, not all implementations use an algorithm as
described in RFC 3517. [RFC3517] sophisticated as that described in RFC 3517.
2.4 TCP MIBs 3.3 Dealing with Forged Segments
The first MIB module defined for use with SNMP (in RFC 1066 and its By default, TCP lacks any cryptographic structures to differentiate
update, RFC 1156) was a single monolithic MIB module, called MIB-I. legitimate segments and those spoofed from malicious hosts. Spoofing
This evolved over time to be MIB-II (RFC 1213). It then became valid segments requires correctly guessing a number of fields. The
apparent that having a single monolithic MIB module was not scalable, documents in this sub-section describe ways to make that guessing
given the number and breadth of MIB data definitions that needed to harder, or prevent it from being able to negatively impact a
be included. Thus, additional MIB modules were defined, and those connection.
parts of MIB-II which needed to evolve were split off. Eventually,
the remaining parts of MIB-II were also split off, with the
TCP-specific part being documented in RFC 2012.
RFC 2012 is the primary document that implementers should presently RFC 1948 I: "Defending Against Sequence Number Attacks" (May 1996)
be concerned with for MIB-II. If implementers desire to support
MIB-I, then RFC 1156 is the document to refer to, although it has
been obsoleted by the MIB-II specification in RFC 1213. Although a
standards track document, RFC 2452 is considered a historic mistake
by the MIB community, as it is based on the idea of parallel IPv4 and
IPv6 structures. The community has decided that while new structures
are needed to accomodate IPv6, a single generic structure for both
IPv4 and IPv6 addresses, to aid in definition, implementation, and
transition between IPv4 and IPv6.
RFC 1156 S: "Management Information Base for Network Management of This document [RFC1948] describes the TCP vulnerability based upon
TCP/IP-based Internets" (May 90) guessing sequence numbers and as well as defenses against this
exploit. Some variation is implemented in most currently-used
operating systems.
This document describes the required MIB fields for TCP RFC 2385 S: "Protection of BGP Sessions via the TCP MD5 Signature
implementations, with minor corrections and no technical changes Option" (August 1998)
from RFC 1066, which it obsoletes. This is the standards track
document for MIB-I. [RFC1156]
RFC 2012 S: "SNMPv2 Management Information Base for the Transmission From document: "This document describes currrent existing practice
Control Protocol using SMIv2" (Nov 96) for securing BGP against certain simple attacks. It is understood
to have security weaknesses against concerted attacks.
This document defines the TCP MIB, updating RFC 1213.[RFC2012] This memo describes a TCP extension to enhance security for BGP.
It defines a new TCP option for carrying an MD5 [RFC1321] digest
in a TCP segment. This digest acts like a signature for that
segment, incorporating information known only to the connection
end points. Since BGP uses TCP as its transport, using this
option in the way described in this paper significantly reduces
the danger from certain security attacks on BGP." [RFC2385]
RFC 2452 S: "IP Version 6 Management Information Base for the TCP MD5 options are currently only used in very limited contexts,
Transmission Control Protocol" (Dec 98) primarily for defending BGP exchanges between routers. Some
deployment notes for those using TCP MD5 are found in the later
RFC 3562, "Key Management Considerations for the TCP MD5 Signature
Option" [RFC3562].
This document augments RFC 2012 by adding an IPv6-specific Work in progress: Transmission Control Protocol Security
connection table. The rest of 2012 holds for any IP version. Considerations (Internet Draft name: draft-ietf-tcpm-tcpsecure)
((Shouldn't 2452 "Update" 2012 ?)) [RFC2452]
3. Special Cases and Implementation Hints At the time of this writing, the TCP Maintenance and Minor
Extensions Working Group is producing a document (edited by Mitesh
Dalal) which describes a challenge-response mechanism for securing
TCP against spoofed control segments. This document is expected
to become an RFC in the near future.
RFC 1144 S: "Compressing TCP/IP headers for low-speed serial links" 4. Experimental Extensions
(Feb 90)
This document contains Van Jacobson's classic specification of The RFCs in this section are still experimental, but may become
TCP/IP header compression. It is notable for its elegance and proposed standards in the future. At least part of the reason that
clarity. [RFC1144] they are still experimental is to gain more wide-scale experience
with them before making a standards track decision.
RFC 1948 I: "Defending Against Sequence Number Attacks" (May 96) RFC 2140 I: "TCP Control Block Interdependence" (April 1997)
The sequence number guessing TCP vulnerability is described in This document [RFC2140] suggests how TCP connections between the
this document and means for defending it from exploitation are same endpoints might share information, such as their congestion
discussed in this document. Some variation is implemented in most control state. To some degree, this is done in practice by a few
modern operating systems. [RFC1948] operating systems; for example, Linux has a destination cache.
RFC 2140 I: "TCP Control Block Interdependence" (Apr 97) A related proposal, the Congestion Manager, is specified in RFC
3124 [RFC3124]. The idea behind the Congestion Manager, moving
congestion control outside of individual TCP connections,
represents a modification to the core of TCP. Although a Proposed
Standard, some pieces of the Congestion Manager support
architecture have not been specified yet, and it has not achieved
use or implementation beyond experimental stacks.
This document suggests how TCP connections between the same RFC 2861 E: "TCP Congestion Window Validation" (June 2000)
endpoints might share information, such as their congestion
control state. To some degree, this is done in practice by a few
modern operating systems. [RFC2140]
RFC 2488 B: "Enhancing TCP Over Satellite Channels using Standard This document [RFC2861] suggests reducing the congestion window
Mechanisms" (Jan 99) over time when no packets are flowing.
From abstract: "While TCP works over satellite channels there are RFC 3465 E: "TCP Congestion Control with Appropriate Byte Counting
several IETF standardized mechanisms that enable TCP to more (ABC)" (February 2003)
effectively utilize the available capacity of the network path.
This document outlines some of these TCP mitigations. At this
time, all mitigations discussed in this document are IETF
standards track mechanisms (or are compliant with IETF
standards)." [RFC2488]
RFC 2525 I: "Known TCP Implementation Problems" (Mar 99) This document [RFC3465] suggests that congestion control use the
number of bytes acknowledged rather than the number of
acknowledgements received. This has been implemented in Linux.
The ABC mechanism behaves differently than the standard means when
there is not a one-to-one relationship between data segments and
acknowledgements. ABC still operates within the accepted
guidelines, but is more robust to delayed ACKs and ACK-division
[Savage].
From abstract: "This memo catalogs a number of known TCP RFC 3522 E: "The Eifel Detection Algorithm for TCP" (April 2003)
implementation problems. The goal in doing so is to improve
conditions in the existing Internet by enhancing the quality of
current TCP/IP implementations." [RFC2525]
RFC 3360 B: "Inappropriate TCP Resets Considered Harmful" (Aug 02) This document [RFC3522] suggests using timestamps to detect
spurious timeouts.
This document is a plea to firewall vendors not to send gratuitous RFC 3540 E: "Robust Explicit Congestion Notification (ECN) signaling
TCP RST (Reset) packets when unassigned TCP header bits are used. with Nonces" (June 2003)
This practice prevents desirable extension and evolution of the
protocol and hence is inimical to the future of the Internet.
[RFC3360]
RFC 3449 B: "TCP Performance Implications of Network Path Asymmetry" This document [RFC3540] suggests a modified ECN to address
(Dec 02) security concerns, and updates RFC 3168.
From abstract: "This document describes TCP performance problems RFC 3649 E: "HighSpeed TCP for Large Congestion Windows" (December
that arise because of asymmetric effects. These problems arise in 2003)
several access networks, including bandwidth-asymmetric networks
and packet radio subnetworks, for different underlying reasons.
However, the end result on TCP performance is the same in both
cases: performance often degrades significantly because of
imperfection and variability in the ACK feedback from the receiver
to the sender. The document details several mitigations to these
effects, which have either been proposed or evaluated in the
literature, or are currently deployed in networks." [RFC3449]
RFC 3481 B: "TCP over Second (2.5G) and Third (3G) Generation This document [RFC3649] suggests a modification to TCP's
Wireless Networks" (Feb 03) steady-state behavior to efficiently use very large windows.
From abstract: "This document describes a profile for optimizing RFC 3708 E: "Using TCP Duplicate Selective Acknowledgement (DSACKs)
TCP to adapt so that it handles paths including second (2.5G) and and Stream Control Transmission Protocol (SCTP) Duplicate
third (3G) generation wireless networks." [RFC3481] Transmission Sequence Numbers (TSNs) to Detect Spurious
Retransmissions" (February 2004)
RFC 3493 I: "Basic Socket Interface Extensions for IPv6" (Feb 03) Abstract: "TCP and Stream Control Transmission Protocol (SCTP)
provide notification of duplicate segment receipt through
Duplicate Selective Acknowledgement (DSACKs) and Duplicate
Transmission Sequence Number (TSN) notification, respectively.
This document presents conservative methods of using this
information to identify unnecessary retransmissions for various
applications." [RFC3708]
This document describes the de facto standard sockets API for RFC 3742 E: "Limited Slow-Start for TCP with Large Congestion
programming with TCP, which is implemented nearly ubiquitously in Windows" (March 2004)
modern operating systems and programming languages. [RFC3493]
4. Experimental TCP Extensions This document [RFC3742] describes a more conservative slow-start
behavior to prevent massive packet losses when a connection uses a
very large window.
These documents may one day join the standards track, but they are Work in progress: Forward RTO-Recovery (F-RTO): An Algorithm for
currently not recommended for implementation. Detecting Spurious Retransmission Timeouts with TCP and SCTP
(Internet Draft name: draft-ietf-tcpm-frto)
RFC 2861 E: "TCP Congestion Window Validation" (Jun 00) The F-RTO detection algorithm provides another option for
inferring spurious retransmission timeouts. At the time of this
writing, the TCP Maintenance and Minor Extensions Working Group
had completed a document describing F-RTO (by Pasi Sarolahti and
Markku Kojo), and planned to make this an Experimental part of the
RFC series, pending IESG review.
Decaying the congestion window if it hasn't been recently 5. Historic Extensions
utilized. [RFC2861]
RFC 3465 E: "TCP Congestion Control with Appropriate Byte Counting The RFCs listed here define extensions that have thus far failed to
(ABC)" (Feb 03) arouse substantial interest, or were found to be defective.
Congestion control using number of bytes acknowledged rather than RFC 1106 "TCP Big Window and NAK Options" (June 1989)
number of acknowledgements received. Implemented in Linux.
[RFC3465]
RFC 3522 E: "The Eifel Detection Algorithm for TCP" (Apr 03) This RFC [RFC1106] defined an alternative to the Window Scale
option for using large windows, and described the "negative
acknowledgement" or NAK option. There is a comparison of NAK and
SACK methods, and early discussion of TCP over satellite issues.
The options described in this document have not been adopted by
the larger community, although NAKs are used in the SCPS-TP
adaptation of TCP, developed by the Consultive Committee for Space
Data Systems (CCSDS).
Use of timestamps to detect spurious timeouts. [RFC3522] RFC 1110 "A Problem with the TCP Big Window Option" (August 1989)
RFC 3540 E: "Robust Explicit Congestion Notification (ECN) signaling Abstract: "The TCP Big Window option discussed in RFC 1106 will
with Nonces" (Jun 03) not work properly in an Internet environment which has both a high
bandwidth * delay product and the possibility of disordering and
duplicating packets. In such networks, the window size must not
be increased without a similar increase in the sequence number
space. Therefore, a different approach to big windows should be
taken in the Internet." [RFC1110]
Modified ECN to address security concerns. [RFC3540] RFC 1146 E "TCP Alternate Checksum Options" (March 1990)
RFC 3649 E: "HighSpeed TCP for Large Congestion Windows" (Dec 03) This document [RFC1146] defined more robust TCP checksums than the
16-bit ones-complement in use today. A typographical error in RFC
1145 is fixed in RFC 1146, otherwise the documents are the same.
A modification to TCP's steady state behavior in order to RFC 1263 "TCP Extensions Considered Harmful" (October 1991)
efficiently use very large windows is described in this document.
RFC 3742 E: "Limited Slow-Start for TCP with Large Congestion This interesting document [RFC1263] argues against "backwards
Windows" (Mar 04) compatible" TCP extensions. Specifically mentioned are several
TCP enhancements that have been successful, including timestamps,
window scaling, PAWS, and SACK. RFC 1263 presents an alternative
approach called "protocol evolution", whereby several evolutionary
versions of TCP would exist on hosts. These distinct TCP versions
would represent upgrades to each other and could be
header-incompatible. Interoperability would be provided by having
a virtualization layer select the right TCP version for a
particular connection. This idea did not catch on with the
community, while the type of extensions RFC 1263 specifically
targeted as harmful did become popular.
This document describes a more conservative slow-start behavoir to RFC 1379 I "Extending TCP for Transactions -- Concepts" (November
prevent massive amounts of loss when connections use very large 1992)
windows. [RFC3742]
5. Deprecated TCP Extensions See RFC 1644.
The RFCs listed here define extensions that failed to arouse RFC 1644 E "T/TCP -- TCP Extensions for Transactions Functional
substantial interest, or were found to be defective. Specification" (July 1994)
RFC 1146 E "TCP Alternate Checksum Options" (Mar 90) The inventors of TCP believed that cached connection state could
have been used to eliminate TCP's 3-way handshake, to support
two-packet request/response exchanges. RFCs 1379 [RFC1379] and
1644 [RFC1644] show that this is far from simple. Furthermore,
T/TCP floundered on the ease of denial-of-service attacks that can
result.
This document defined a mechanism for using TCP checksums other RFC 1693 E "An Extension to TCP: Partial Order Service" (November
than the 16-bit ones-complement, which might be more robust. 1994)
[RFC1146]
RFC 1379 I "Extending TCP for Transactions -- Concepts" (Nov 92) This document [RFC1693] defines a TCP extension for applications
that do not care about the order in which application-layer
objects are received. Examples are multimedia and database
applications. In practice, these applications either accept the
possible performance loss because of TCP's strict ordering, or
they use more specialized transport protocols.
See RFC 1644. [RFC1379] 6. Support Documents
RFC 1644 E "T/TCP -- TCP Extensions for Transactions Functional This section contains several classes of documents that do not
Specification" (Jul 94) necessarily define current protocol behaviors, but are nevertheless
of interest to TCP implementors. Section 6.1 describes several
foundational RFCs that give modern readers a better understanding of
the principles underlying TCP's behaviors and development over the
years. The documents listed in Section 6.2 provide advice on using
TCP in various types of network situations that pose challenges above
those of typical wired links. Some implementation notes can be found
in Section 6.3. The TCP Management Information Bases are described
in Section 6.4. RFCs that describe tools for testing and debugging
TCP implementations or contain high-level tutorials on the protocol
are listed Section 6.5, while Section 6.6 lists a number of case
studies that have explored TCP performance.
The inventors of T/TCP believed that cached connection state could 6.1 Foundational Works
be used to eliminate TCP's 3-way handshake, to support single-
packet request/response exchanges. RFCs 1379 and 1644 show that
it is far from simple. Furthermore, T/TCP floundered on the ease
of denial-of-service attacks that can result. [RFC1644]
RFC 1693 E "An Extension to TCP: Partial Order Service" (Nov 94) The documents listed in this section contain information that is
largely duplicated by the standards documents previously discussed.
However, some of them contain a greater depth of problem statement
explanation or other context. Particularly, RFCs 813-817 (known as
the "Dave Clark Five"), describe some early problems and solutions
(RFC 815 only describes the reassembly of IP fragments, and is not
included here).
This document defines a TCP extension for applications where the RFC 813: "Window and Acknowledgement Strategy in TCP" (July 1982)
order that application layer objects are received in is relatively
unimportant, citing multimedia and database applications as
examples. In practice, these applications either made due with
the mismatch of standard TCP for their goals, or used other more
specialized transport protocols. [RFC1693]
6. Case Studies and Protocol Analysis This document [RFC0813] contains an early discussion of Silly
Window Syndrome and its avoidance, and motivates and describes the
use of delayed acknowledgements.
RFC 1337 I: "TIME-WAIT Assassination Hazards in TCP" (May 92) RFC 814: "Name, Addresses, Ports, and Routes" (July 1982)
This document points out a problem with acting on received reset Suggestions and guidance for the design of tables and algorithms
segments while in the TIME-WAIT state. The main reccommendation to keep track of various identifiers within a TCP/IP
is that hosts in TIME-WAIT ignore resets. [RFC1337] implementation are provided by this document [RFC0814].
RFC 2415 I: "Simulation Studies of Increased Initial TCP Window Size" RFC 816: "Fault Isolation and Recovery" (July 1982)
(Sep 98)
Results of some simulations using TCP initial windows greater than In this document [RFC0816], TCP's response to indications of
1 segment are presented in this document. The analysis indicates network error conditions such as timeouts or received ICMP
that user-perceived performance can be improved by increasing the messages.
initial window to 3 segments. [RFC2415]
RFC 2416 I: "When TCP Starts Up With Four Packets Into Only Three RFC 817: "Modularity and Efficiency in Protocol Implementation" (July
Buffers" (Sep 98) 1982)
This document uses simulation results to clear up some concerns This document [RFC0817] contains implementation suggestions that
about using an initial window of 4 segments when the network path are general and not TCP-specific. However they have been used to
has less provisioning. [RFC2416] develop TCP implementations and describe some performance
implications of the interactions between various layers in the
Internet stack.
RFC 2760 I: "Ongoing TCP Research Related to Satellites" (Feb 00) RFC 872: "TCP-ON-A-LAN" (September 1982)
This document discusses the advantages and disadvantages of Conclusion: "The sometimes-expressed fear that using TCP on a
several different experimental means of improving TCP performance local net is a bad idea is unfounded." [RFC0872]
over long-delay or error-prone paths. These include: T/TCP,
larger initial windows, byte counting, delayed acknowledgements,
slow start thresholds, NewReno and SACK-based loss recovery, FACK
[FACK], ECN, various corruption-detection mechanisms, congestion
avoidance changes for fairness, use of multiple parallel flows,
pacing, header compression, state sharing, and ACK congestion
control, filtering, and reconstruction. [RFC2760]
RFC 2884 I: "Performance Evaluation of Explicit Congestion RFC 896: "Congestion Control in IP/TCP Internetworks" (January 1984)
Notification (ECN) in IP Networks" (Jul 00)
This document describes experimental results that show some This document [RFC0896] contains some early experiences with
improvements to the performance of both short and long-lived congestion collapse and some initial thoughts on how to avoid it
connections due to ECN. [RFC2884] using congestion control in TCP.
RFC 2914 B: "Congestion Control Principles" (Sep 00) RFC 964: "Some Problems with the Specification of the Military
Standard Transmission Control Protocol" (November 1985)
The use of end-to-end congestion control for preventing congestion This document [RFC0964] was prepared by the US Military to define
collapse and providing fairness to TCP is motivated by this TCP in greater detail than RFC 793. A few serious specification
document. [RFC2914] bugs are detailed in RFC 964, reminding us of the difficulty in
RFC 2923 I: "TCP Problems with Path MTU Discovery" (Sep 00) specification writing (even when working from existing
documents!).
From abstract: "This memo catalogs several known Transmission RFC 1072: "TCP Extensions for Long-Delay Paths" (October 1988)
Control Protocol (TCP) implementation problems dealing with Path
Maximum Transmission Unit Discovery (PMTUD), including the
long-standing black hole problem, stretch acknowlegements (ACKs)
due to confusion between Maximum Segment Size (MSS) and segment
size, and MSS advertisement based on PMTU." [RFC2923]
RFC 2963 I: "A Rate Adaptive Shaper for Differentiated Services" (Oct This document [RFC1072] contains early explanations of the
mechanisms that were later described by RFCs 1323 and 2018, which
obsolete it.
RFC 1185: "TCP Extension for High-Speed Paths" (October 1990)
This document [RFC1185] builds on RFC 1072 to describe more
advanced strategies for dealing with sequence number wrapping and
detecting duplicates from earlier connections. This document was
obsoleted by RFC 1323.
RFC 2914 B: "Congestion Control Principles" (September 2000)
This document [RFC2914] motivates the use of end-to-end congestion
control for preventing congestion collapse and providing fairness
to TCP.
6.2 Difficult Network Environments
As the internetworking field has explored wireless, satellite,
cellular telephone, and other kinds of link-layer technologies, a
large body of work has built up on enhancing TCP performance for such
links. The RFCs listed in this section describe some of these more
challenging network environments and how TCP interacts with them.
RFC 2488 B: "Enhancing TCP Over Satellite Channels using Standard
Mechanisms" (January 1999)
From abstract: "While TCP works over satellite channels there are
several IETF standardized mechanisms that enable TCP to more
effectively utilize the available capacity of the network path.
This document outlines some of these TCP mitigations. At this
time, all mitigations discussed in this document are IETF
standards track mechanisms (or are compliant with IETF
standards)." [RFC2488]
RFC 2757 I: "Long Thin Networks" (January 2000)
Several methods of improving TCP performance over long thin
networks, such as geosynchronous satellite links, are discussed in
this document [RFC2757]. A particular set of TCP options is
developed that should work well in such environments, and be safe
to use in the global Internet.
RFC 2760 I: "Ongoing TCP Research Related to Satellites" (February
2000) 2000)
This document describes how TCP performance can be improved in This document [RFC2760] discusses the advantages and disadvantages
diffserv networks using rate adaptive shapers and color markers. of several different experimental means of improving TCP
[RFC2963] performance over long-delay or error-prone paths. These include:
T/TCP, larger initial windows, byte counting, delayed
acknowledgements, slow start thresholds, NewReno and SACK-based
loss recovery, FACK [FACK], ECN, various corruption-detection
mechanisms, congestion avoidance changes for fairness, use of
multiple parallel flows, pacing, header compression, state
sharing, and ACK congestion control, filtering, and
reconstruction. While RFC 2488 looks at standard extensions, this
document focuses on more experimental means of performance
enhancement.
RFC 3135 I: "Performance Enhancing Proxies Intended to Mitigate RFC 3135 I: "Performance Enhancing Proxies Intended to Mitigate
Link-Related Degradations" (Jun 01) Link-Related Degradations" (June 2001)
From abstract: "This document is a survey of Performance Enhancing From abstract: "This document is a survey of Performance Enhancing
Proxies (PEPs) often employed to improve degraded TCP performance Proxies (PEPs) often employed to improve degraded TCP performance
caused by characteristics of specific link environments, for caused by characteristics of specific link environments, for
example, in satellite, wireless WAN, and wireless LAN example, in satellite, wireless WAN, and wireless LAN
environments. Different types of Performance Enhancing Proxies environments. Different types of Performance Enhancing Proxies
are described as well as the mechanisms used to improve are described as well as the mechanisms used to improve
performance." [RFC3135] performance." [RFC3135]
7. Tools and Tutorials RFC 3449 B: "TCP Performance Implications of Network Path Asymmetry"
(December 2002)
RFC 1180 I: "TCP/IP Tutorial" (Jan 91) This document is an extremely From abstract: "This document describes TCP performance problems
brief overview of the TCP/IP protocol suite as a whole. It gives that arise because of asymmetric effects. These problems arise in
some explanation as to how and where TCP fits in. [RFC1180] several access networks, including bandwidth-asymmetric networks
and packet radio subnetworks, for different underlying reasons.
However, the end result on TCP performance is the same in both
cases: performance often degrades significantly because of
imperfection and variability in the ACK feedback from the receiver
to the sender.
RFC 1470 I: "FYI on a Network Management Tool Catalog: Tools for The document details several mitigations to these effects, which
Monitoring and Debugging TCP/IP Internets and Interconnected Devices" have either been proposed or evaluated in the literature, or are
(Jun 93) currently deployed in networks." [RFC3449]
A few of the tools that this document describes are still RFC 3481 B: "TCP over Second (2.5G) and Third (3G) Generation
maintained and in use today, such as ttcp and tcpdump, however, Wireless Networks" (February 2003)
many of the tools described do not related specifically to TCP and
are no longer used or easily available. [RFC1470]
RFC 2398 I: "Some Testing Tools for TCP Implementors" (Aug 98) From abstract: "This document describes a profile for optimizing
TCP to adapt so that it handles paths including second (2.5G) and
third (3G) generation wireless networks." [RFC3481]
A number of TCP packet generation and analysis tools are described RFC 3819 B: "Advice for Internet Subnetwork Designers" (July 2004)
in this document. While some of these tools are no longer readily
available or widely used, for the most part they are still
relevant and useable. [RFC2398]
8. Historical This document [RFC3819] describes how TCP performance can be
negatively impacted by some particular lower-layer behaviors, and
provides guidance in designing lower-layer networks and protocols
to be amicable to TCP.
The documents listed in this section contain information that is 6.3 Implementation Advice
largely duplicated by the standards documents in Section 2, however
some of them contain a greater depth of problem statement
explanation, or other historical context.
RFC 813: "Window and Acknowledgement Strategy in TCP" (July 82) RFC 879: "The TCP Maximum Segment Size and Related Topics" (November
1983)
This document contains an early discussion of Silly Window Abstract: 'This memo discusses the TCP Maximum Segment Size Option
Syndrome and its avoidance, and motivates and describes the use of and related topics. The purposes is to clarify some aspects of
delayed acknowledgements. [RFC0813] TCP and its interaction with IP. This memo is a clarification to
the TCP specification, and contains information that may be
considered as "advice to implementers".' [RFC0879]
RFC 817: "Modularity and Efficiency in Protocol Implementation" (July RFC 2525 I: "Known TCP Implementation Problems" (March 1999)
82)
The suggestions for implementation in this document are general From abstract: "This memo catalogs a number of known TCP
and not TCP-specific, however they have been used to develop TCP implementation problems. The goal in doing so is to improve
implementations and describe some performance implications of the conditions in the existing Internet by enhancing the quality of
interactions between various layers in the Internet stack. current TCP/IP implementations." [RFC2525]
[RFC0817]
RFC 876: "The TCP Maximum Segment Size and Related Topics" (Nov 83) RFC 2923 I: "TCP Problems with Path MTU Discovery" (September 2000)
Abstract: This memo discusses the TCP Maximum Segment Size Option From abstract: "This memo catalogs several known Transmission
and related topics. The purposes is to clarify some aspects of Control Protocol (TCP) implementation problems dealing with Path
TCP and its interaction with IP. This memo is a clarification to Maximum Transmission Unit Discovery (PMTUD), including the
the TCP specification, and contains information that may be long-standing black hole problem, stretch acknowlegements (ACKs)
considered as "advice to implementers". [RFC0876] due to confusion between Maximum Segment Size (MSS) and segment
size, and MSS advertisement based on PMTU." [RFC2923]
RFC 896: "Congestion Control in IP/TCP Internetworks" (Jan 84) RFC 3360 B: "Inappropriate TCP Resets Considered Harmful" (August
2002)
This document contains some early experiences with congestion This document [RFC3360] is a plea that firewall vendors not send
collapse and some initial thoughts on how to avoid it using gratuitous TCP RST (Reset) packets when unassigned TCP header bits
congestion control in TCP. [RFC0896] are used. This practice prevents desirable extension and
evolution of the protocol and hence is inimical to the future of
the Internet.
RFC 964: "Some Problems with the Specification of the Military RFC 3493 I: "Basic Socket Interface Extensions for IPv6" (February
Standard Transmission Control Protocol" (Nov 85) 2003)
The US Military wrote their own document defining TCP in addition This document [RFC3493] describes the de facto standard sockets
to RFC 793. A few serious specification bugs are detailed in RFC API for programming with TCP. This API is implemented nearly
964, reminding us of the difficulty in specification writing (even ubiquitously in modern operating systems and programming
when working from existing documents!). [RFC0964] languages.
RFC 1066: "Management Information Base for Network Management of 6.4 Management Information Bases
TCP/IP-based Internets" (Aug 88)
This was the first document describing the TCP MIB. It is The first MIB module defined for use with SNMP (in RFC 1066 and its
obsoleted by RFC 1156. [RFC1066] update, RFC 1156) was a single monolithic MIB module, called MIB-I.
This evolved over time to be MIB-II (RFC 1213). It then became
apparent that having a single monolithic MIB module was not scalable,
given the number and breadth of MIB data definitions that needed to
be included. Thus, additional MIB modules were defined, and those
parts of MIB-II which needed to evolve were split off. Eventually,
the remaining parts of MIB-II were also split off, with the
TCP-specific part being documented in RFC 2012.
RFC 1072: "TCP Extensions for Long-Delay Paths" (Oct 88) RFC 2012 is the primary document for MIB-II. MIB-I, defined in RFC
1156, has been obsoleted by the MIB-II specification in RFC 1213
(updated by 2012). Work is in progress, at the time of this writing,
on a document that incorporates IPv6 and updates and obsoletes RFC
2012 (currently in the form of draft-ietf-ipv6-rfc2012-update, edited
by Rajiv Raghunarayan, under submission to the IESG as a Proposed
Standard).
Early explanations of the mechanisms that were later described by RFC 1066: "Management Information Base for Network Management of
RFCs 1323 and 2018 are found in this document. [RFC1072] TCP/IP-based Internets" (August 1988)
RFC 1185: "TCP Extension for High-Speed Paths" (Oct 90) This document [RFC1066] was the description of the TCP MIB. It
was obsoleted by RFC 1156.
More advanced strategies for dealing with sequence number wrapping RFC 1156 S: "Management Information Base for Network Management of
and detecting duplicates from earlier connections are outlined in TCP/IP-based Internets" (May 1990)
this document that builds on RFC 1072. [RFC1185]
This document [RFC1156] describes the required MIB fields for TCP
implementations, with minor corrections and no technical changes
from RFC 1066, which it obsoletes. This is the standards track
document for MIB-I.
RFC 1213 S: "Management Information Base for Network Management of RFC 1213 S: "Management Information Base for Network Management of
TCP/IP-based Internets: MIB-II" (Mar 91) TCP/IP-based Internets: MIB-II" (March 1991)
This document describes the second version of the MIB in a This document [RFC1213] describes the second version of the MIB in
monolithic form. RFC 2012 updates this document, by splitting out a monolithic form. RFC 2012 updates this document by splitting
the TCP-specific portions. [RFC1213] out the TCP-specific portions.
9. Security Considerations RFC 2012 S: "SNMPv2 Management Information Base for the Transmission
Control Protocol using SMIv2" (November 1996)
This document [RFC2012] defines the TCP MIB, updating RFC 1213.
RFC 2452 S: "IP Version 6 Management Information Base for the
Transmission Control Protocol" (December 1998)
This document [RFC2452] augments RFC 2012 by adding an
IPv6-specific connection table. The rest of 2012 holds for any IP
version.
Although it is a standards track document, RFC 2452 is considered
a historic mistake by the MIB community, as it is based on the
idea of parallel IPv4 and IPv6 structures. Although IPv6 requires
new structures, the community has decided to define a single
generic structure for both IPv4 and IPv6. This will aid in
definition, implementation, and transition between IPv4 and IPv6.
6.5 Tools and Tutorials
RFC 1180 I: "TCP/IP Tutorial" (January 1991)
This document [RFC1180] is an extremely brief overview of the
TCP/IP protocol suite as a whole. It gives some explanation as to
how and where TCP fits in.
RFC 1470 I: "FYI on a Network Management Tool Catalog: Tools for
Monitoring and Debugging TCP/IP Internets and Interconnected Devices"
(June 1993)
A few of the tools that this document [RFC1470] describes are
still maintained and in use today, for example ttcp and tcpdump.
However, many of the tools described do not relate specifically to
TCP and are no longer used or easily available.
RFC 2398 I: "Some Testing Tools for TCP Implementors" (August 1998)
This document [RFC2398] describes a number of TCP packet
generation and analysis tools. While some of these tools are no
longer readily available or widely used, for the most part they
are still relevant and useable.
6.6 Case Studies
RFC 1337 I: "TIME-WAIT Assassination Hazards in TCP" (May 1992)
This document [RFC1337] points out a problem with acting on
received reset segments while in the TIME-WAIT state. The main
recemmendation is that hosts in TIME-WAIT ignore resets.
RFC 2415 I: "Simulation Studies of Increased Initial TCP Window Size"
(September 1998)
This document [RFC2415] presents results of some simulations using
TCP initial windows greater than 1 segment. The analysis
indicates that user-perceived performance can be improved by
increasing the initial window to 3 segments.
RFC 2416 I: "When TCP Starts Up With Four Packets Into Only Three
Buffers" (September 1998)
This document [RFC2416] uses simulation results to clear up some
concerns about using an initial window of 4 segments when the
network path has less provisioning.
RFC 2884 I: "Performance Evaluation of Explicit Congestion
Notification (ECN) in IP Networks" (July 2000)
This document [RFC2884] describes experimental results that show
some improvements to the performance of both short and long-lived
connections due to ECN.
7. Security Considerations
This document introduces no new security considerations. Each RFC This document introduces no new security considerations. Each RFC
listed in this document attempts to address the security listed in this document attempts to address the security
considerations of the proposals it contains. considerations of the specification it contains.
10. Acknowledgments 8. Acknowledgments
This document grew out of a discussion on the end2end-interest This document grew out of a discussion on the end2end-interest
mailing list, the public list of the End-to-End Research Group of the mailing list, the public list of the End-to-End Research Group of the
IRTF. We thank Joe Touch and Reiner Ludwig for their contributions, IRTF. We thank Joe Touch, Reiner Ludwig, and Pekka Savola for their
in particular. The chairs of the TCPM working group, Mark Allman and contributions, in particular. The chairs of the TCPM working group,
Ted Faber, have been instrumental in the development of this Mark Allman and Ted Faber, have been instrumental in the development
document. Keith McCloghrie provided some useful notes and of this document. Keith McCloghrie provided some useful notes and
clarification on the various MIB-related RFCs. clarification on the various MIB-related RFCs.
11. References 9. References
11.1 Core Specification 9.1 Basic Functionality
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7, RFC [RFC0793] Postel, J., "Transmission Control Protocol", STD 7, RFC
793, September 1981. 793, September 1981.
[RFC1122] Braden, R., "Requirements for Internet Hosts - [RFC1122] Braden, R., "Requirements for Internet Hosts -
Communication Layers", STD 3, RFC 1122, October 1989. Communication Layers", STD 3, RFC 1122, October 1989.
[RFC1156] McCloghrie, K. and M. Rose, "Management Information Base [RFC2147] Borman, D., "TCP and UDP over IPv6 Jumbograms", RFC 2147,
for network management of TCP/IP-based internets", RFC May 1997.
1156, May 1990.
[RFC1323] Jacobson, V., Braden, B. and D. Borman, "TCP Extensions
for High Performance", RFC 1323, May 1992.
[RFC2012] McCloghrie, K., "SNMPv2 Management Information Base for
the Transmission Control Protocol using SMIv2", RFC 2012,
November 1996.
[RFC2018] Mathis, M., Mahdavi, J., Floyd, S. and A. Romanow, "TCP
Selective Acknowledgment Options", RFC 2018, October 1996.
[RFC2452] Daniele, M., "IP Version 6 Management Information Base for [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
the Transmission Control Protocol", RFC 2452, December (IPv6) Specification", RFC 2460, December 1998.
1998.
[RFC2581] Allman, M., Paxson, V. and W. Stevens, "TCP Congestion [RFC2581] Allman, M., Paxson, V. and W. Stevens, "TCP Congestion
Control", RFC 2581, April 1999. Control", RFC 2581, April 1999.
[RFC2873] Xiao, X., Hannan, A., Paxson, V. and E. Crabbe, "TCP [RFC2873] Xiao, X., Hannan, A., Paxson, V. and E. Crabbe, "TCP
Processing of the IPv4 Precedence Field", RFC 2873, June Processing of the IPv4 Precedence Field", RFC 2873, June
2000. 2000.
[RFC2988] Paxson, V. and M. Allman, "Computing TCP's Retransmission
Timer", RFC 2988, November 2000.
9.2 Standard Enhancements
[RFC1323] Jacobson, V., Braden, B. and D. Borman, "TCP Extensions
for High Performance", RFC 1323, May 1992.
[RFC1948] Bellovin, S., "Defending Against Sequence Number Attacks",
RFC 1948, May 1996.
[RFC2018] Mathis, M., Mahdavi, J., Floyd, S. and A. Romanow, "TCP
Selective Acknowledgment Options", RFC 2018, October 1996.
[RFC2385] Heffernan, A., "Protection of BGP Sessions via the TCP MD5
Signature Option", RFC 2385, August 1998.
[RFC2883] Floyd, S., Mahdavi, J., Mathis, M. and M. Podolsky, "An [RFC2883] Floyd, S., Mahdavi, J., Mathis, M. and M. Podolsky, "An
Extension to the Selective Acknowledgement (SACK) Option Extension to the Selective Acknowledgement (SACK) Option
for TCP", RFC 2883, July 2000. for TCP", RFC 2883, July 2000.
[RFC2988] Paxson, V. and M. Allman, "Computing TCP's Retransmission
Timer", RFC 2988, November 2000.
[RFC3042] Allman, M., Balakrishnan, H. and S. Floyd, "Enhancing [RFC3042] Allman, M., Balakrishnan, H. and S. Floyd, "Enhancing
TCP's Loss Recovery Using Limited Transmit", RFC 3042, TCP's Loss Recovery Using Limited Transmit", RFC 3042,
January 2001. January 2001.
[RFC3168] Ramakrishnan, K., Floyd, S. and D. Black, "The Addition of [RFC3168] Ramakrishnan, K., Floyd, S. and D. Black, "The Addition of
Explicit Congestion Notification (ECN) to IP", RFC 3168, Explicit Congestion Notification (ECN) to IP", RFC 3168,
September 2001. September 2001.
[RFC3390] Allman, M., Floyd, S. and C. Partridge, "Increasing TCP's [RFC3390] Allman, M., Floyd, S. and C. Partridge, "Increasing TCP's
Initial Window", RFC 3390, October 2002. Initial Window", RFC 3390, October 2002.
[RFC3517] Blanton, E., Allman, M., Fall, K. and L. Wang, "A [RFC3517] Blanton, E., Allman, M., Fall, K. and L. Wang, "A
Conservative Selective Acknowledgment (SACK)-based Loss Conservative Selective Acknowledgment (SACK)-based Loss
Recovery Algorithm for TCP", RFC 3517, April 2003. Recovery Algorithm for TCP", RFC 3517, April 2003.
[RFC3562] Leech, M., "Key Management Considerations for the TCP MD5
Signature Option", RFC 3562, July 2003.
[RFC3782] Floyd, S., Henderson, T. and A. Gurtov, "The NewReno [RFC3782] Floyd, S., Henderson, T. and A. Gurtov, "The NewReno
Modification to TCP's Fast Recovery Algorithm", RFC 3782, Modification to TCP's Fast Recovery Algorithm", RFC 3782,
April 2004. April 2004.
11.2 Special Cases and Implementation Hints 9.3 Experimental Extensions
[RFC1144] Jacobson, V., "Compressing TCP/IP headers for low-speed
serial links", RFC 1144, February 1990.
[RFC1948] Bellovin, S., "Defending Against Sequence Number Attacks",
RFC 1948, May 1996.
[RFC2140] Touch, J., "TCP Control Block Interdependence", RFC 2140, [RFC2140] Touch, J., "TCP Control Block Interdependence", RFC 2140,
April 1997. April 1997.
[RFC2488] Allman, M., Glover, D. and L. Sanchez, "Enhancing TCP Over
Satellite Channels using Standard Mechanisms", BCP 28, RFC
2488, January 1999.
[RFC2525] Paxson, V., Dawson, S., Fenner, W., Griner, J., Heavens,
I., Lahey, K., Semke, J. and B. Volz, "Known TCP
Implementation Problems", RFC 2525, March 1999.
[RFC3360] Floyd, S., "Inappropriate TCP Resets Considered Harmful",
BCP 60, RFC 3360, August 2002.
[RFC3449] Balakrishnan, H., Padmanabhan, V., Fairhurst, G. and M.
Sooriyabandara, "TCP Performance Implications of Network
Path Asymmetry", BCP 69, RFC 3449, December 2002.
[RFC3481] Inamura, H., Montenegro, G., Ludwig, R., Gurtov, A. and F.
Khafizov, "TCP over Second (2.5G) and Third (3G)
Generation Wireless Networks", BCP 71, RFC 3481, February
2003.
[RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J. and W.
Stevens, "Basic Socket Interface Extensions for IPv6", RFC
3493, February 2003.
11.3 Experimental TCP Extensions
[RFC2861] Handley, M., Padhye, J. and S. Floyd, "TCP Congestion [RFC2861] Handley, M., Padhye, J. and S. Floyd, "TCP Congestion
Window Validation", RFC 2861, June 2000. Window Validation", RFC 2861, June 2000.
[RFC3124] Balakrishnan, H. and S. Seshan, "The Congestion Manager",
RFC 3124, June 2001.
[RFC3465] Allman, M., "TCP Congestion Control with Appropriate Byte [RFC3465] Allman, M., "TCP Congestion Control with Appropriate Byte
Counting (ABC)", RFC 3465, February 2003. Counting (ABC)", RFC 3465, February 2003.
[RFC3522] Ludwig, R. and M. Meyer, "The Eifel Detection Algorithm [RFC3522] Ludwig, R. and M. Meyer, "The Eifel Detection Algorithm
for TCP", RFC 3522, April 2003. for TCP", RFC 3522, April 2003.
[RFC3540] Spring, N., Wetherall, D. and D. Ely, "Robust Explicit [RFC3540] Spring, N., Wetherall, D. and D. Ely, "Robust Explicit
Congestion Notification (ECN) Signaling with Nonces", RFC Congestion Notification (ECN) Signaling with Nonces", RFC
3540, June 2003. 3540, June 2003.
[RFC3649] Floyd, S., "HighSpeed TCP for Large Congestion Windows", [RFC3649] Floyd, S., "HighSpeed TCP for Large Congestion Windows",
RFC 3649, December 2003. RFC 3649, December 2003.
[RFC3708] Blanton, E. and M. Allman, "Using TCP Duplicate Selective
Acknowledgement (DSACKs) and Stream Control Transmission
Protocol (SCTP) Duplicate Transmission Sequence Numbers
(TSNs) to Detect Spurious Retransmissions", RFC 3708,
February 2004.
[RFC3742] Floyd, S., "Limited Slow-Start for TCP with Large [RFC3742] Floyd, S., "Limited Slow-Start for TCP with Large
Congestion Windows", RFC 3742, March 2004. Congestion Windows", RFC 3742, March 2004.
11.4 Deprecated TCP Extensions 9.4 Historic Extensions
[RFC1106] Fox, R., "TCP big window and NAK options", RFC 1106, June
1989.
[RFC1110] McKenzie, A., "Problem with the TCP big window option",
RFC 1110, August 1989.
[RFC1146] Zweig, J. and C. Partridge, "TCP alternate checksum [RFC1146] Zweig, J. and C. Partridge, "TCP alternate checksum
options", RFC 1146, March 1990. options", RFC 1146, March 1990.
[RFC1263] O'Malley, S. and L. Peterson, "TCP Extensions Considered
Harmful", RFC 1263, October 1991.
[RFC1379] Braden, B., "Extending TCP for Transactions -- Concepts", [RFC1379] Braden, B., "Extending TCP for Transactions -- Concepts",
RFC 1379, November 1992. RFC 1379, November 1992.
[RFC1644] Braden, B., "T/TCP -- TCP Extensions for Transactions [RFC1644] Braden, B., "T/TCP -- TCP Extensions for Transactions
Functional Specification", RFC 1644, July 1994. Functional Specification", RFC 1644, July 1994.
[RFC1693] Connolly, T., Amer, P. and P. Conrad, "An Extension to TCP [RFC1693] Connolly, T., Amer, P. and P. Conrad, "An Extension to TCP
: Partial Order Service", RFC 1693, November 1994. : Partial Order Service", RFC 1693, November 1994.
11.5 Case Studies and Protocol Analysis 9.5 Support Documents
[RFC0813] Clark, D., "Window and Acknowledgement Strategy in TCP",
RFC 813, July 1982.
[RFC0814] Clark, D., "Name, addresses, ports, and routes", RFC 814,
July 1982.
[RFC0816] Clark, D., "Fault isolation and recovery", RFC 816, July
1982.
[RFC0817] Clark, D., "Modularity and efficiency in protocol
implementation", RFC 817, July 1982.
[RFC0872] Padlipsky, M., "TCP-on-a-LAN", RFC 872, September 1982.
[RFC0879] Postel, J., "TCP maximum segment size and related topics",
RFC 879, November 1983.
[RFC0896] Nagle, J., "Congestion control in IP/TCP internetworks",
RFC 896, January 1984.
[RFC0964] Sidhu, D. and T. Blumer, "Some problems with the
specification of the Military Standard Transmission
Control Protocol", RFC 964, November 1985.
[RFC1066] McCloghrie, K. and M. Rose, "Management Information Base
for network management of TCP/IP-based internets", RFC
1066, August 1988.
[RFC1072] Jacobson, V. and R. Braden, "TCP extensions for long-delay
paths", RFC 1072, October 1988.
[RFC1156] McCloghrie, K. and M. Rose, "Management Information Base
for network management of TCP/IP-based internets", RFC
1156, May 1990.
[RFC1180] Socolofsky, T. and C. Kale, "TCP/IP tutorial", RFC 1180,
January 1991.
[RFC1185] Jacobson, V., Braden, B. and L. Zhang, "TCP Extension for
High-Speed Paths", RFC 1185, October 1990.
[RFC1213] McCloghrie, K. and M. Rose, "Management Information Base
for Network Management of TCP/IP-based internets:MIB-II",
STD 17, RFC 1213, March 1991.
[RFC1337] Braden, B., "TIME-WAIT Assassination Hazards in TCP", RFC [RFC1337] Braden, B., "TIME-WAIT Assassination Hazards in TCP", RFC
1337, May 1992. 1337, May 1992.
[RFC1470] Enger, R. and J. Reynolds, "FYI on a Network Management
Tool Catalog: Tools for Monitoring and Debugging TCP/IP
Internets and Interconnected Devices", RFC 1470, June
1993.
[RFC2012] McCloghrie, K., "SNMPv2 Management Information Base for
the Transmission Control Protocol using SMIv2", RFC 2012,
November 1996.
[RFC2398] Parker, S. and C. Schmechel, "Some Testing Tools for TCP
Implementors", RFC 2398, August 1998.
[RFC2415] Poduri, K., "Simulation Studies of Increased Initial TCP [RFC2415] Poduri, K., "Simulation Studies of Increased Initial TCP
Window Size", RFC 2415, September 1998. Window Size", RFC 2415, September 1998.
[RFC2416] Shepard, T. and C. Partridge, "When TCP Starts Up With [RFC2416] Shepard, T. and C. Partridge, "When TCP Starts Up With
Four Packets Into Only Three Buffers", RFC 2416, September Four Packets Into Only Three Buffers", RFC 2416, September
1998. 1998.
[RFC2452] Daniele, M., "IP Version 6 Management Information Base for
the Transmission Control Protocol", RFC 2452, December
1998.
[RFC2488] Allman, M., Glover, D. and L. Sanchez, "Enhancing TCP Over
Satellite Channels using Standard Mechanisms", BCP 28, RFC
2488, January 1999.
[RFC2525] Paxson, V., Allman, M., Dawson, S., Fenner, W., Griner,
J., Heavens, I., Lahey, K., Semke, J. and B. Volz, "Known
TCP Implementation Problems", RFC 2525, March 1999.
[RFC2757] Montenegro, G., Dawkins, S., Kojo, M., Magret, V. and N.
Vaidya, "Long Thin Networks", RFC 2757, January 2000.
[RFC2760] Allman, M., Dawkins, S., Glover, D., Griner, J., Tran, D., [RFC2760] Allman, M., Dawkins, S., Glover, D., Griner, J., Tran, D.,
Henderson, T., Heidemann, J., Touch, J., Kruse, H., Henderson, T., Heidemann, J., Touch, J., Kruse, H.,
Ostermann, S., Scott, K. and J. Semke, "Ongoing TCP Ostermann, S., Scott, K. and J. Semke, "Ongoing TCP
Research Related to Satellites", RFC 2760, February 2000. Research Related to Satellites", RFC 2760, February 2000.
[RFC2884] Hadi Salim, J. and U. Ahmed, "Performance Evaluation of [RFC2884] Hadi Salim, J. and U. Ahmed, "Performance Evaluation of
Explicit Congestion Notification (ECN) in IP Networks", Explicit Congestion Notification (ECN) in IP Networks",
RFC 2884, July 2000. RFC 2884, July 2000.
[RFC2914] Floyd, S., "Congestion Control Principles", BCP 41, RFC [RFC2914] Floyd, S., "Congestion Control Principles", BCP 41, RFC
2914, September 2000. 2914, September 2000.
[RFC2923] Lahey, K., "TCP Problems with Path MTU Discovery", RFC [RFC2923] Lahey, K., "TCP Problems with Path MTU Discovery", RFC
2923, September 2000. 2923, September 2000.
[RFC2963] Bonaventure, O. and S. De Cnodder, "A Rate Adaptive Shaper
for Differentiated Services", RFC 2963, October 2000.
[RFC3135] Border, J., Kojo, M., Griner, J., Montenegro, G. and Z. [RFC3135] Border, J., Kojo, M., Griner, J., Montenegro, G. and Z.
Shelby, "Performance Enhancing Proxies Intended to Shelby, "Performance Enhancing Proxies Intended to
Mitigate Link-Related Degradations", RFC 3135, June 2001. Mitigate Link-Related Degradations", RFC 3135, June 2001.
11.6 Tools and Tutorials [RFC3360] Floyd, S., "Inappropriate TCP Resets Considered Harmful",
BCP 60, RFC 3360, August 2002.
[RFC1180] Socolofsky, T. and C. Kale, "TCP/IP tutorial", RFC 1180,
January 1991.
[RFC1470] Enger, R. and J. Reynolds, "FYI on a Network Management
Tool Catalog: Tools for Monitoring and Debugging TCP/IP
Internets and Interconnected Devices", RFC 1470, June
1993.
[RFC2151] Kessler, G. and S. Shepard, "A Primer On Internet and
TCP/IP Tools and Utilities", RFC 2151, June 1997.
[RFC2398] Parker, S. and C. Schmechel, "Some Testing Tools for TCP
Implementors", RFC 2398, August 1998.
11.7 Historical
[RFC0813] Clark, D., "Window and Acknowledgement Strategy in TCP",
RFC 813, July 1982.
[RFC0817] Clark, D., "Modularity and efficiency in protocol
implementation", RFC 817, July 1982.
[RFC0876] Smallberg, D., "Survey of SMTP implementations", RFC 876,
September 1983.
[RFC0896] Nagle, J., "Congestion control in IP/TCP internetworks",
RFC 896, January 1984.
[RFC0964] Sidhu, D. and T. Blumer, "Some problems with the [RFC3449] Balakrishnan, H., Padmanabhan, V., Fairhurst, G. and M.
specification of the Military Standard Transmission Sooriyabandara, "TCP Performance Implications of Network
Control Protocol", RFC 964, November 1985. Path Asymmetry", BCP 69, RFC 3449, December 2002.
[RFC1066] McCloghrie, K. and M. Rose, "Management Information Base [RFC3481] Inamura, H., Montenegro, G., Ludwig, R., Gurtov, A. and F.
for network management of TCP/IP-based internets", RFC Khafizov, "TCP over Second (2.5G) and Third (3G)
1066, August 1988. Generation Wireless Networks", BCP 71, RFC 3481, February
2003.
[RFC1072] Jacobson, V. and R. Braden, "TCP extensions for long-delay [RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J. and W.
paths", RFC 1072, October 1988. Stevens, "Basic Socket Interface Extensions for IPv6", RFC
3493, February 2003.
[RFC1185] Jacobson, V., Braden, B. and L. Zhang, "TCP Extension for [RFC3819] Karn, P., Bormann, C., Fairhurst, G., Grossman, D.,
High-Speed Paths", RFC 1185, October 1990. Ludwig, R., Mahdavi, J., Montenegro, G., Touch, J. and L.
Wood, "Advice for Internet Subnetwork Designers", BCP 89,
RFC 3819, July 2004.
[RFC1213] McCloghrie, K. and M. Rose, "Management Information Base 9.6 Informative References Outside the RFC Series
for Network Management of TCP/IP-based internets:MIB-II",
STD 17, RFC 1213, March 1991.
11.8 Informative References Ouside the RFC Series [FACK] Mathis, M. and J. Mahdavi, "Forward Acknowledgement:
Refining TCP Congestion Control", ACM SIGCOMM, August 1996.
[FACK] Mathis, M. and J. Mahdavi, "Forward Acknowledgement: Refining [Karn] Karn, P. and C. Partridge, "Round Trip Time Estimation",
TCP Congestion Control", ACM SIGCOMM, August 1996. ACM SIGCOMM, August 1987.
[karn] Karn, P. and C. Partridge, "Round Trip Time Estimation", ACM [Savage] Savage, S., Cardwell, N., Wetherall, D. and T. Anderson,
SIGCOMM, August 1987. "TCP Congestion Control with a Misbehaving Receiver", ACM
Computer Communication Review 29 (5), October 1999.
[vj88] Jacobson, V., "Congestion Avoidance and Control", ACM [VJ88] Jacobson, V., "Congestion Avoidance and Control", ACM
SIGCOMM, August 1988. SIGCOMM, August 1988.
Authors' Addresses Authors' Addresses
Martin Duke Martin Duke
Boeing Phantom Works Boeing Phantom Works
PO Box 3707, MC 3W-51 PO Box 3707, MC 3W-51
Seattle, WA 98124-2207 Seattle, WA 98124-2207
Phone: 253-657-8203 Phone: 253-657-8203
skipping to change at page 26, line 41 skipping to change at page 32, line 41
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights. except as set forth therein, the authors retain all their rights.
Acknowledgment Acknowledgment
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is currently provided by the
Internet Society. Internet Society.
 End of changes. 

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