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draft-hc-requirements-delta-01.txt
Hello All,
Here is a draft describing some proposed additions/modifications to the
existing header compression requirements draft,
draft-degermark-hc-requirements-00.txt
http://search.ietf.org/internet-drafts/draft-degermark-hc-requirements-00.tx
t. I am submitting on behalf of several authors (see draft) .
My apologies for the delay in posting this material. Comments are welcome!
Regards,
Chris Clanton
Nokia Research Center - Dallas
Mobile Networks Lab
<<draft-hc-requirements-delta-01.txt>>
IETF ROHC Working Group Chris Clanton
INTERNET-DRAFT Khiem Le
Zhigang Liu
22 March 2000 Nokia Research Center
Expires 22 Sepember 2000 Mohammad Mahloujian
Ericsson Radio Systems AB
Nat Natarajan, Motorola
Donglin Shen
AT&T Wireless Services
James Womack, Motorola
IP/UDP/RTP Header Compression Proposed Modifications and Additions
<draft-hc-requirements-delta-01.txt>
Status of This Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Abstract
This contribution proposes a set additions/modifications to the
current ROHC draft requirements for IP/UDP/RTP header compression
[1].
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Table of Contents
Status of This Memo . . . . . . . . . . . . . . . . . . . . . . . . i
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. PROPOSED MODIFICATIONS TO EXISTING REQUIRMENTS . . . . . . . . . 2
2.1. Performance/Spectral Efficiency . . . . . . . . . . . . . . 2
2.2. IPv6 or IPv4 . . . . . . . . . . . . . . . . . . . . . . . . 2
2.3. Ubiquity . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.4. Cellular HO . . . . . . . . . . . . . . . . . . . . . . . . 2
2.5. Integrity . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.6. Error Propogation . . . . . . . . . . . . . . . . . . . . . 3
2.7. Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.8. Packet Loss . . . . . . . . . . . . . . . . . . . . . . . . 3
2.9. Media Supported . . . . . . . . . . . . . . . . . . . . . . 4
2.10. Independence With Respect to Call Type . . . . . . . . . . 4
3. PROPOSED NEW REQUIREMENTS . . . . . . . . . . . . . . . . . . . . 5
3.1. Packet Misordering . . . . . . . . . . . . . . . . . . . . . 5
3.2. Operation on Unidirectional Links . . . . . . . . . . . . . 5
3.3. Configurable Header Size Fluctuation . . . . . . . . . . . . 5
3.4. Processing Delay . . . . . . . . . . . . . . . . . . . . . . 6
3.5. Complexity . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.6. Generic Applicability . . . . . . . . . . . . . . . . . . . 6
3.7. Compatibility with Other Schemes . . . . . . . . . . . . . . 6
4. References . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
This contribution proposes a set additions/modifications to the
current ROHC draft requirements for IP/UDP/RTP header compression
[1]. Those requirements are based on requirements in [2]. Section 2
describes proposed modifications to the existing requirements in [1].
Section 3 describes a set of new requirements which we believe should
be added.
It is a fundamental requirement for both GERAN (specified by ETSI
SMG2 standards group) and UTRAN (specified by 3GPP standards
organization) to support end-to-end IP real time services, such as
voice over IP and real time data in their respective Release 2000
specifications. In order to achieve the required spectral
efficiency, it is mandatory to develop/standardize an effective
IP/UDP/RTP header compression scheme that is suitable for cellular
applications before completion of the Release 2000 standards. The
current IETF ROHC charter timeline indicates milestones/goals which
we believe would be in line with the completion schedules of both
ETSI and 3GPP. Due to the fact that this work is a critical part of
Release 2000 standardization, it should be reiterated that it is
imperative for this work to be completed on schedule.
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2. PROPOSED MODIFICATIONS TO EXISTING REQUIRMENTS
We address each existing requirement in order below. In each case,
requirement name, actual requirement text, and/or the associated
justification text may have a proposed change.
2.1. Performance/Spectral Efficiency
Requirement: "Must provide low relative overhead under expected
operating conditions; compression efficiency should
be better than RFC2508 under similar error
conditions"
Justification: "In general, a primary goal is high spectral
efficiency. Reduction of overhead has direct impact.
Notes: Relative overhead is the header overhead
relative to the payload; performance should take into
account usage of any auxiliary (e.g. control or
feedback) channels during operation of the scheme."
2.2. IPv6 or IPv4
Justification: "Ipv4 and Ipv6 terminals are expected to coexist for
some time. Note: compression efficiency when
processing IPv6 packets may not be the same as IPv4."
2.3. Ubiquity
No change.
2.4. Cellular HO
Requirement: "Must support the cellular handoff operation; the
disruption when the header compression scheme is
present shall not be longer than when there is no
header compression; loss of compression efficiency,
even temporary, shall be minimized; must be lossless
after handoff"
Justification: "A target application is adaptation of user plane
traffic transmitted on cellular air interfaces;
therefore this operation must be supported. Minimum
disruption of the compression process is desired
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because there can otherwise be negative impacts on
spectral efficiency and voice quality."
2.5. Integrity
Justification: "Would like to maintain the end-to-end integrity of
IP. Lossless here refers to ability to reconstruct
the transmitted header exactly at the receiver."
2.6. Error Propogation
Requirement: "Error propagation due to header compression should
be kept to an absolute minimum; error propagation is
defined as the loss of packets subsequent to the one
where the error actually occurred, even when those
subsequent packets contain no errors."
2.7. Delay
Name: Delay and Jitter
Requirement: "Must operate under all expected delay/jitter
conditions."
Justification: "The user may be in different types of network
environments with different characteristics."
2.8. Packet Loss
Requirement: "Must operate under all expected packet loss
conditions; prefer that header compression efficiency
is as independent of packet loss rate as possible;
the packet loss could occur prior to, or after the
compressor."
Justification: "The user may be in different types of environments
with different characteristics, e.g., packet loss
could occur prior to the compressor on the downlink
if there is loss in the IP network. Ability to
adjust scheme parameters should be possible in order
to enable optimizations for specific operating
conditions (e.g., if it is known that with particular
radio technology there is seldom loss of several
consecutive packets in a row, compressed sequence
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number may require fewer bits to prevent wrap-around
ambiguity)."
2.9. Media Supported
No change.
2.10. Independence With Respect to Call Type
Requirement: "Must function for mobile-to-mobile, landline to
mobile and mobile-to-landline calls; performance in
each case should be comparable to existing cellular
(in terms of both quality and spectral efficiency)"
Justification: change the word "both" to "All".
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3. PROPOSED NEW REQUIREMENTS
The requirements below are being proposed as additions to the current
list.
3.1. Packet Misordering
Requirement: "Compressor must be able to function without failure
even when packets are misordered."
Justification: "Packet misordering may occur upstream relative to
the compressor; this is especially true on the
downlink in cellular systems employing header
compression, since packets are arriving from an IP
network; it should be possible to adjust relevant
scheme parameters in order to enable optimizations
for specific operating conditions (e.g., if it is
known that there is significant misordering prior to
compressor, a smaller compressed sequence number
might suffice)."
3.2. Operation on Unidirectional Links
Requirement: "Must include some provision for operation on links
which do not have a corresponding feedback channel."
Justification: "The header compression scheme should be capable of
functioning on simplex links; however, use of a
feedback channel should not be precluded (likely
performance increase)."
3.3. Configurable Header Size Fluctuation
Requirement: "Scheme should support various degrees of header size
fluctuation."
Justification: "Depending on the radio technology in use, various
levels of header size fluctuation may be supported in
an optimal way; efficiency gained through the use of
more flexible radio bearer architecture should not be
precluded."
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3.4. Processing Delay
Requirement: "Processing delay and related delay jitter should be
minimized; the delay/jitter introduced by the header
compression process should not cause the target
system delay budget to be exceeded."
Justification: "The service quality of conversation applications is
very sensitive to processing/propagation delay and
delay jitter. Processing delay should be independent
of round-trip time/transmission bandwidth available."
3.5. Complexity
Requirement: "Implementation complexity should be minimized."
Justification: "Implementation complexity should be such that the
scheme can execute in a processing power-limited
device (mobile phone), but still be easily scaled up
for use in devices which handle multiple flows
(infrastructure)."
3.6. Generic Applicability
Requirement: "The algorithm must be independent of the link
capabilities of the various radio technologies."
Justification: "Header compression is envisioned for radio
technologies with differing capabilities, e.g., EDGE,
WCDMA, CDMA 2000 etc."
3.7. Compatibility with Other Schemes
Requirement: "Header compression scheme should not preclude the
coexistence of other header adaptation schemes."
Justification: "Several different header adaptation schemes may
operate within the same system. The particular scheme
selected is negotiated at set-up time. Its selection
will depend upon the transport protocol, e.g.
RTP/UDP/IP, UDP/IP, TCP/IP, etc."
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4. References
[1] 3GPP Requirements for Header Compression, <draft-degermark-hc-
requirements-00.txt>
[2] 3rd Generation Partnership Project, Services and Systems Aspects
Technical Specification Group, "Architecture for All-IP
Networks", 3G TR 23.922 version 1.00.
[3] S. Casner, V. Jacobson. "Compressing IP/UDP/RTP Headers for Low-
Speed Serial Links", Internet Engineering Task Force (IETF) RFC
2508, February 1999.
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5. Authors' Addresses
Chris Clanton
Nokia
6000 Connection Drive
Irving, Texas 75039
USA
Phone: +1 972-894-4886
Fax: +1 972-894-4589
Email: christopher.clanton@nokia.com
Khiem Le
Nokia
6000 Connection Drive
Irving, Texas 75039
USA
Phone: +1 972-894-4882
Fax: +1 972-894-4589
Email: khiem.le@nokia.com
Zhigang Liu
Nokia
6000 Connection Drive
Irving, Texas 75039
USA
Phone: +1 972-894-5935
Fax: +1 972-894-4589
Email: zhigang.liu@nokia.com
Mohammad Mahloujian
Ericsson Radio Systems AB
S-164 80 Stockholm, Sweden
Phone: +46 (0)8 585 321 13
Fax: +46 (0)8 404 46 13
Email: mohammad.mahloujian@era.ericsson.se
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Nat Natarajan
Motorola
Arlington Heights, IL 60004
Phone: +1 847-632-6303
Email: ann004@email.mot.com
Donglin Shen
AT&T Wireless Services
P.O. Box 97061
Redmond WA 98073
USA
Phone: +1 425-580-7614
Fax: +1 425-580-6765
Email: donglin.shen@attws.com
Jim Womack, Ph.D.
Motorola
Advanced Technology & Software Organization
Phone: +1 817-245-2853
Email: James.Womack@motorola.com
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