draft-ietf-mobileip-qos-requirements-01.txt   draft-ietf-mobileip-qos-requirements-02.txt 
IETF Mobile IP Working Group Hemant Chaskar IETF Mobile IP Working Group Hemant Chaskar
INTERNET-DRAFT Editor INTERNET-DRAFT Editor
Nokia Research Center Nokia Research Center
20 August 2001 10 February 2002
Requirements of a QoS Solution for Mobile IP Requirements of a QoS Solution for Mobile IP
draft-ietf-mobileip-qos-requirements-01.txt draft-ietf-mobileip-qos-requirements-02.txt
Status of This Memo Status of This Memo
This document is an Internet-Draft and is in full conformance This document is an Internet-Draft and is in full conformance
with all provisions of Section 10 of RFC2026. with all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet other groups may also distribute working documents as Internet
Drafts. Drafts.
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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.
Copyright Notice Copyright Notice
Copyright (c) The Internet Society (2001). All rights reserved. Copyright (c) The Internet Society (2001). All rights reserved.
Abstract Abstract
Mobile IP protocol ensures correct routing of packets to mobile Mobile IP ensures correct routing of packets to mobile node as the
node as the mobile node changes its point of attachment with the mobile node changes its point of attachment to the Internet.
Internet. However, it is also required to provide proper QoS However, it is also required to provide proper QoS forwarding
forwarding treatment to mobile node's packet stream at the treatment to mobile node's packet stream at the intermediate nodes
intermediate nodes in the network, so that QoS-sensitive IP in the network, so that QoS-sensitive IP services can be supported
services can be supported over Mobile IP. This document describes over Mobile IP. This document describes requirements for an IP QoS
requirements of an IP QoS mechanism for its satisfactory operation mechanism for its satisfactory operation with Mobile IP.
with Mobile IP.
1 Introduction 1 Introduction
Mobile IP is a technology that allows a "mobile node" (MN) to Mobile IP is a technology that allows a "mobile node" (MN) to
change its point of attachment to the Internet while change its point of attachment to the Internet while
communicating with the "correspondent node" (CN) using IP. The communicating with the "correspondent node" (CN) using IP. The
formal description of Mobile IP can be found in [1, 2]. Mobile IP formal description of Mobile IP can be found in [1, 2]. Mobile IP
primarily addresses the correct routing of packets to MN's current primarily addresses the correct routing of packets to MN's current
point of attachment with the Internet. point of attachment with the Internet.
It is also essential to provide proper Quality of Service (QoS) It is also essential to provide proper Quality of Service (QoS)
forwarding treatment to the packets sent by or destined to MN forwarding treatment to the packets sent by or destined to MN as
as they propagate along different routes in the network due to they propagate along different routes in the network due to node
node mobility. This document will identify the requirements that mobility. This document will identify the requirements that Mobile
Mobile IP places on an IP QoS mechanism. IP places on an IP QoS mechanism.
1.1 Problem statement 1.1 Problem statement
When a MN using Mobile IP undergoes handover from one access When an MN using Mobile IP undergoes handover from one access
router to another, the path traversed by MN's packet stream in the router to another, the path traversed by MN's packet stream in the
network may change. Such a change may be limited to a small network may change. Such a change may be limited to a small
segment of the end-to-end path near the extremity, or it could segment of the end-to-end path near the extremity, or it could
also have an end-to-end impact. Further, the packets belonging to also have an end-to-end impact. Further, the packets belonging to
MN's ongoing session may start using the new care-of address after MN's ongoing session may start using a new care-of address after
handover. Hence, they may not be recognized by some forwarding handover. Hence, they may not be recognized by some forwarding
functions in the nodes even along that segment of the end-to-end functions in the nodes even along that segment of the end-to-end
path that remains unaltered after handover. path that remains unaltered after handover. Finally, handover may
Finally, handover may occur between the subnets that are under occur between the subnets that are under different
different administrative control. administrative control.
In the light of this scenario, it is essential to establish proper In the light of this scenario, it is essential to establish proper
QoS support for the MN's packet stream along the new packet path. QoS support for the MN's packet stream along the new packet path.
1.2 An approach for solving QoS problem in Mobile IP 1.2 An approach for solving QoS problem in Mobile IP
There are four important steps involved in solving the QoS problem There are four important steps involved in solving the QoS problem
for Mobile IP. They are as follows: (1) List the requirements that for Mobile IP. They are as follows: (1) List the requirements that
Mobile IP places on the QoS mechanism, (2) Evaluate current IP QoS Mobile IP places on the QoS mechanism, (2) Evaluate current IP QoS
solutions against the requirements, (3) Decide if current solutions against these requirements, (3) Decide if current
solutions need to be extended, or if new ones need to be solutions need to be extended, or if new ones need to be defined,
defined, and (4) Depending on the result of step 3, define new and (4) Depending on the result of step 3, define new solutions or
solutions or fix the old ones. fix the old ones.
Of these, the first step, i.e. the requirements step, is addressed Of these, the first step, i.e. the requirements step, is addressed
in this draft. The last three steps are not dealt with here in in this draft. The last three steps are not dealt with here in
detail. However, so as to create useful insight into the Mobile IP detail. However, so as to create useful insight into the Mobile IP
QoS problem, at times this document highlights the QoS problem, at times this document highlights the shortcomings of
shortcomings of some well known current proposals for some well known current proposals for establishing QoS support for
establishing QoS support for the packet stream in the network, the packet stream in the network, when directly used with
with respect to the requirements imposed by Mobile IP. Mobile IP.
2 Terminology 2 Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in RFC 2119. this document are to be interpreted as described in RFC 2119.
3 Requirements of a QoS solution for Mobile IP 3 Requirements of a QoS solution for Mobile IP
This section describes the requirements of a QoS solution for This section describes the requirements for a QoS solution for its
Mobile IP. Conversely, note that only Mobile IP-specific satisfactory operation with Mobile IP. Conversely, note that only
requirements are described here. We do not assume any particular Mobile IP-specific requirements are described here. We do not
version (4 or 6) of IP while describing the requirements. assume any particular version (4 or 6) of IP while describing the
Solutions can be designed for IPv4 and IPv6 independently, or a requirements. Solutions can be designed for IPv4 and IPv6
single solution can be designed to work with both versions. independently, or a single solution can be designed to work with
both versions.
In this document, we assume that the target access router for In this document, we assume that the target access router for
MN's handover is already pinned down by other protocols. For MN's handover is already pinned down by other protocols. For
example, Seamoby working group has started work on candidate example, Seamoby working group has started work on the candidate
access router discovery protocols [3]. Thus, any QoS-capability access router discovery protocols [3]. Thus, any QoS-capability
specific negotiations that may affect the handover decision are specific negotiations that may affect the handover decision are
outside the scope of QoS solution as such, rather need to be outside the scope of QoS solution as such, rather need to be
performed by candidate and target access router selection performed by candidate and target access router selection
protocols. protocols.
3.1 Performance requirements 3.1 Performance requirements
1. Minimize the interruption in QoS at the time of handover: 1. Minimize the interruption in QoS at the time of handover:
At the time of handover, interruption in QoS would occur if the At the time of handover, interruption in QoS would occur if the
packets sent by or destined to the MN arrive at the intermediate packets sent by or destined to the MN arrive at the intermediate
node in the new packet path without that node having node in the new packet path without that node having information
information about their QoS forwarding requirement. Then, those about their QoS forwarding requirement. Then, those packets will
packets will receive default forwarding treatment. Such QoS receive default forwarding treatment. Such QoS interruption MUST
interruption MUST be minimized. A good metric for this performance be minimized. A good metric for this performance is the number of
is the number of packets that may potentially get served with the "default" QoS at the packets that may potentially get served with the "default" QoS at
time of handover. The number of such packets MUST be minimized. the time of handover. The number of such packets MUST be minimized.
As an example, this performance metric is computed in [4] for the As an example, this performance metric is computed in [4] for the
case of end-to-end RSVP signaling [5] with Mobile IPv6. It is case of end-to-end RSVP signaling [5] with Mobile IPv6. It is
shown there that when the end-to-end path of packets changes at shown there that when the end-to-end path of packets changes at
large after handover or when the care-of address changes after large after handover or when the care-of address changes after
handover, OPWA (One Pass With Advertisement) model of reservation handover, OPWA (One Pass With Advertisement) model of reservation
used by RSVP causes the latency of about one round-trip time used by RSVP causes the latency of about one round-trip time
between the MN and the CN before QoS can be established along the between the MN and the CN before QoS can be established along the
new packet path. In other words, the packets using the new care-of new packet path. In other words, the packets using the new care-of
address that would be released by the MN or the CN during one address that would be released by the MN or the CN during one
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3.2 Interoperability requirements 3.2 Interoperability requirements
1. Interoperability with mobility protocols: 1. Interoperability with mobility protocols:
A number of mobility protocols that are complementary to Mobile IP A number of mobility protocols that are complementary to Mobile IP
are already defined or may be defined in future in IETF, are already defined or may be defined in future in IETF,
particularly in Mobile IP and Seamoby working groups. particularly in Mobile IP and Seamoby working groups.
Examples are Fast Handover [8, 9], Regional Registrations [10], Examples are Fast Handover [8, 9], Regional Registrations [10],
Hierarchical MIPv6 [11], Context Transfer [12] etc. The QoS Hierarchical MIPv6 [11], Context Transfer [12] etc. The QoS
mechanism for Mobile IP SHOULD take advantage of these mobility mechanism for Mobile IP SHOULD take advantage of these mobility
protocols for the optimized operation. However, the QoS scheme protocols for the optimized operation. However, the QoS scheme
MUST have provisions to accomplish its tasks even if one or more MUST have provisions to accomplish its tasks even if one or more
of these mobility protocols are not used. of these mobility protocols are not used.
2. Interoperability with heterogeneous packet paths as 2. Interoperability with heterogeneous packet paths as
regards QoS paradigms: regards QoS paradigms:
The new path after handover, of the MN's packet stream, may The new path after handover, of the MN's packet stream, may
traverse network domains employing different QoS paradigms traverse network domains employing different QoS paradigms
compared to those along the old path. The QoS mechanism for compared to those along the old path. The QoS mechanism for Mobile
Mobile IP MUST be able to establish proper QoS forwarding IP SHOULD be able to establish proper QoS forwarding treatment for
treatment for the MN's packet stream along the packet paths the MN's packet stream along the packet paths deploying different
deploying different QoS paradigms (best current practices), QoS paradigms (best current practices), in a manner consistent
in a manner consistent with the QoS mechanism deployed along with the QoS mechanism deployed along those paths.
those paths.
As an illustration, suppose that the MN is currently attached to As an illustration, suppose that the MN is currently attached to
an access router which is the edge router of a DiffServ network, an access router which is the edge router of a DiffServ network,
and that the packet classifier and traffic policer for the MN's and that the packet classifier and traffic policer for the MN's
flows are presently programmed in this access router. Now, suppose flows are presently programmed in this access router. Now, suppose
that the MN needs to be handed over to the access router which is that the MN needs to be handed over to the access router which is
at the edge of an IntServ network. The new access network would at the edge of an IntServ network. The new access network would
expect the exchange of RSVP messages so that proper QoS expect the exchange of RSVP messages so that proper QoS
forwarding treatment can be established for the MN's packet stream forwarding treatment can be established for the MN's packet stream
in that access network. QoS mechanism for Mobile IP MUST have in that access network. QoS mechanism for Mobile IP SHOULD have
provisions to handle such heterogeneity as regards the QoS provisions to handle such heterogeneity as regards the QoS
mechanisms deployed along different packet paths. mechanisms deployed along different packet paths.
3.3 Miscellaneous requirements 3.3 Miscellaneous requirements
1. QoS support along multiple packet paths: 1. QoS support along multiple packet paths:
After MN undergoes handover from one access router to another, After MN undergoes handover from one access router to another,
potentially, there could be multiple paths over which MN's packet potentially, there could be multiple paths over which MN's packet
may propagate. Examples of these path are: route-optimized path may propagate. Examples of these path are: route-optimized path
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requirements such as scalability, security, conservation of requirements such as scalability, security, conservation of
wireless bandwidth, low processing overhead on mobile terminals, wireless bandwidth, low processing overhead on mobile terminals,
providing hooks for authorization and accounting, and robustness providing hooks for authorization and accounting, and robustness
against failures of any Mobile IP-specific QoS components in the against failures of any Mobile IP-specific QoS components in the
network. While it is not possible to set quantitative targets for network. While it is not possible to set quantitative targets for
these desirable properties, the QoS solution MUST be evaluated these desirable properties, the QoS solution MUST be evaluated
against these criteria. against these criteria.
4 Recommendation 4 Recommendation
In this document, we described the requirements of a QoS solution In this document, we described the requirements for a QoS solution
for Mobile IP. The expectation is that the appropriate working for its satisfactory operation with Mobile IP. The expectation is
group will use this requirements document to provide a QoS that the appropriate working group will use this requirements
solution for Mobile IP. document to provide a QoS solution for Mobile IP.
5 Acknowledgment 5 Acknowledgment
I would like to acknowledge the participants of the mailing list I would like to acknowledge the participants of the mailing list
that was set up to discuss the above requirements. Their that was set up to discuss the above requirements. Their
contributions and active participation in the discussion on the contributions and active participation in the discussion on the
mailing list were very useful in the preparation of this document. mailing list were very useful in the preparation of this document.
Special thanks are due to, in alphabetical order, Marc Greis Special thanks are due to, in alphabetical order, Marc Greis
(Nokia), Glenn Morrow (Nortel), Phil Roberts (Megisto) and Michael (Nokia), Glenn Morrow (Nortel), Phil Roberts (Megisto) and Michael
Thomas (Cisco) for their comments during the preparation of Thomas (Cisco) for their input during the preparation of
this document. this document.
6 References 6 References
[1] IP Mobility Support, C. Perkins (Editor), RFC 2002, October 1996. [1] IP mobility support, C. Perkins (Editor), RFC 2002, October 1996.
[2] Mobility Support in IPv6, D. Johnson and C. Perkins, [2] Mobility support in IPv6, D. Johnson and C. Perkins,
draft-ietf-mobileip-ipv6-13.txt, draft-ietf-mobileip-ipv6-13.txt,
work in progress, November 2000. work in progress, November 2000.
[3] Issues in candidate access router discovery for seamless IP [3] Issues in Candidate Access Router discovery for seamless IP
handoffs, D. Trossen et. al., handoffs, D. Trossen et. al.,
draft-ietf-seamoby-cardiscovery-issues-00.txt, draft-ietf-seamoby-cardiscovery-issues-00.txt,
work in progress, July 2001. work in progress, July 2001.
[4] A Framework for QoS Support in Mobile IPv6, H. Chaskar and [4] QoS support in Mobile IP version 6, H. Chaskar and R. Koodli,
R. Koodli, draft-chaskar-mobileip-qos-01.txt, IEEE Broadband Wireless Summit (Networld+Interop), May 2001.
work in progress, March 2001.
[5] A Framework for Integrated Services Operation over Diffserv [5] A Framework for Integrated Services operation over Diffserv
Networks, Yoram Bernet et. al., RFC 2998, November 2000. networks, Y. Bernet et. al., RFC 2998, November 2000.
[6] Analysis of Mobile IP and RSVP Interactions, Michael Thomas, [6] Analysis of Mobile IP and RSVP interactions, M. Thomas,
draft-thomas-seamoby-rsvp-analysis-00.txt, draft-thomas-seamoby-rsvp-analysis-00.txt,
work in progress, February 2001. work in progress, February 2001.
[7] Resource ReSerVation Protocol -- Version 1 Functional [7] Resource ReSerVation Protocol -- Version 1 Functional
Specification, R. Braden et. al., RFC 2750, September 1997. Specification, R. Braden et. al., RFC 2750, September 1997.
[8] Low Latency Handoffs in Mobile IPv4, MIPv4 Handoffs Design Team, [8] Low latency handoffs in Mobile IPv4, MIPv4 Handoffs Design Team,
draft-ietf-mobileip-lowlatency-handoffs-v4-00.txt, draft-ietf-mobileip-lowlatency-handoffs-v4-00.txt,
work in progress, February 2001. work in progress, February 2001.
[9] Fast Handovers for Mobile IPv6, MIPv6 Handover Design Team, [9] Fast handovers for Mobile IPv6, MIPv6 Handover Design Team,
draft-ietf-mobileip-fast-mipv6-01.txt, draft-ietf-mobileip-fast-mipv6-01.txt,
work in progress, April 2001. work in progress, April 2001.
[10] Mobile IPv6 Regional Registrations, J. Malinen, Frank Le , and [10] Mobile IPv6 Regional Registrations, J. Malinen, Frank Le , and
C. Perkins, draft-malinen-mobileip-regreg6-01.txt, C. Perkins, draft-malinen-mobileip-regreg6-01.txt,
work in progress, March 2001. work in progress, March 2001.
[11] Hierarchical MIPv6 Mobility Management, H. Soliman, [11] Hierarchical MIPv6 mobility management, H. Soliman,
C. Castelluccia, K. El-Malki, and L. Bellier, C. Castelluccia, K. El-Malki, and L. Bellier,
draft-ietf-mobileip-hmipv6-02.txt, draft-ietf-mobileip-hmipv6-02.txt,
work in progress, February 2001. work in progress, February 2001.
[12] Context Transfer Framework for Seamless Mobility, R. Koodli and [12] Problem description: Reasons for performing context transfers
C. Perkins, draft-koodli-seamoby-ctv6-00.txt, between nodes in an IP Access Network, edited by J. Kempf,
work in progress, February 2001. draft-ietf-seamoby-context-transfer-problem-stat-04.txt,
work in progress, May 2002.
7 Addresses 7 Addresses
The working group can be contacted via the current chairs: The working group can be contacted via the current chairs:
Basavaraj Patil Phil Roberts Basavaraj Patil Phil Roberts
Nokia Corporation Megisto Nokia Corporation Megisto
6000 Connection Drive 20251 Century Blvd, Suite 120 6000 Connection Drive 20251 Century Blvd, Suite 120
Irving, Texas 75039, USA Germantown, MD 20874 Irving, Texas 75039, USA Germantown, MD 20874
Phone: +1 972-894-6709 Phone: +1 847-202-9314 Phone: +1 972-894-6709 Phone: +1 847-202-9314
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1. A clarification is added at the beginning of Section 3, which 1. A clarification is added at the beginning of Section 3, which
states that QoS-capability negotiations that may affect states that QoS-capability negotiations that may affect
handover decision are outside the scope of this document. handover decision are outside the scope of this document.
2. Section 3.1.2 was reworded for better clarity. 2. Section 3.1.2 was reworded for better clarity.
3. Section 3.2.2 was reworded for better clarity. 3. Section 3.2.2 was reworded for better clarity.
4. Section 3.4 is now called "Standard Requirements" rather than 4. Section 3.4 is now called "Standard Requirements" rather than
"Obvious Requirements". "Obvious Requirements".
5. Section 4 is now called "Recommendation" rather than 5. Section 4 is now called "Recommendation" rather than
"Concluding Remarks". "Concluding Remarks".
Changes Made from 01 Version
The following changes were made from 01 version in response to
IESG comments.
1. Requirement 3.2(2) is changed from MUST to SHOULD.
2. IESG was concerned about the references to too many individual
submissions in the 01 version. Now, individual submission
references 4 and 12 in 01 version are replaced by a reference
to IEEE conference paper and Seamoby WG document, respectively.
However, no alternatives could be found for 6, 10 and 11.
Nevertheless the content in these individual submissions is
important to understand certain requirements. Hence, these
references are not removed.
 End of changes. 

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