draft-briscoe-tsvwg-cl-phb-02.txt   draft-briscoe-tsvwg-cl-phb-03.txt 
TSVWG B. Briscoe TSVWG B. Briscoe
Internet Draft P. Eardley Internet Draft P. Eardley
draft-briscoe-tsvwg-cl-phb-02.txt D. Songhurst draft-briscoe-tsvwg-cl-phb-03.txt D. Songhurst
Expires: December 2006 BT Expires: April 2006 BT
F. Le Faucheur F. Le Faucheur
A. Charny A. Charny
V. Liatsos V. Liatsos
Cisco Systems, Inc Cisco Systems, Inc
J. Babiarz J. Babiarz
K. Chan K. Chan
S. Dudley S. Dudley
Nortel Nortel
G. Karagiannis G. Karagiannis
University of Twente / Ericsson University of Twente / Ericsson
A. Bader A. Bader
L. Westberg L. Westberg
Ericsson Ericsson
26 June, 2006 20 October, 2006
Pre-Congestion Notification marking Pre-Congestion Notification marking
draft-briscoe-tsvwg-cl-phb-02.txt draft-briscoe-tsvwg-cl-phb-03.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that By submitting this Internet-Draft, each author represents that
any applicable patent or other IPR claims of which he or she is 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 aware have been or will be disclosed, and any of which he or she
becomes aware will be disclosed, in accordance with Section 6 of becomes aware will be disclosed, in accordance with Section 6 of
BCP 79. BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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 December 2006. This Internet-Draft will expire on October 2006.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2006). All Rights Reserved. Copyright (C) The Internet Society (2006). All Rights Reserved.
Abstract Abstract
Pre-Congestion Notification (PCN) builds on the concepts of RFC 3168, Pre-Congestion Notification (PCN) builds on the concepts of RFC 3168,
"The addition of Explicit Congestion Notification to IP". However, "The addition of Explicit Congestion Notification to IP". However,
Pre-Congestion Notification aims at providing notification before any Pre-Congestion Notification aims at providing notification before any
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parameters is the next step. parameters is the next step.
Due to time constraints, we were able to simulate a single Due to time constraints, we were able to simulate a single
"congestion point" only, i.e. there was a single router where pre- "congestion point" only, i.e. there was a single router where pre-
congestion notification for admission control and/or pre-emption was congestion notification for admission control and/or pre-emption was
triggered. Furthermore, admission control and flow pre-emption triggered. Furthermore, admission control and flow pre-emption
simulations were performed independently. A study of the interaction simulations were performed independently. A study of the interaction
of admission control and flow pre-emption is also a subject of future of admission control and flow pre-emption is also a subject of future
work. work.
A further performance evaluation study is presented in [Zhang].
5. Encoding the Admission Marked and Pre-emption Marked states 5. Encoding the Admission Marked and Pre-emption Marked states
In this Section we describe one proposal for how to encode the In this Section we describe one proposal for how to encode the
Admission Marking and Pre-emption Marking states in a packet, i.e. Admission Marking and Pre-emption Marking states in a packet, i.e.
what change to make to which bits of a packet. what change to make to which bits of a packet.
The encoding scheme uses the two ECN (Explicit Congestion The encoding scheme uses the two ECN (Explicit Congestion
Notification) bits in the IP header. The four ECN codepoints are used Notification) bits in the IP header. The four ECN codepoints are used
as follows: as follows:
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The transport layer (e.g. TCP) must respond, in terms of congestion The transport layer (e.g. TCP) must respond, in terms of congestion
control, to a *single* CE packet as it would to a packet drop. control, to a *single* CE packet as it would to a packet drop.
The advantage of setting the CE codepoint as an indication of The advantage of setting the CE codepoint as an indication of
congestion, instead of relying on packet drops, is that it allows the congestion, instead of relying on packet drops, is that it allows the
receiver(s) to receive the packet, thus avoiding the potential for receiver(s) to receive the packet, thus avoiding the potential for
excessive delays due to retransmissions after packet losses. excessive delays due to retransmissions after packet losses.
10. Appendix B - Details of simulations 10. Appendix B - Details of simulations
This section provides some details on the simulation study reference The results of the simulation study referred to in Section 4 are presented
in Section 4. below. Further evaluation can be found in [Zhang].
Note that the pdf version of this document includes graphs of
simulation results that aren't in the text version.
10.1. Network and signalling model 10.1. Network and signalling model
In most simulations, the network is modelled as a single link between In most simulations, the network is modelled as a single link between
an ingress and an egress node, all flows sharing the same link. an ingress and an egress node, all flows sharing the same link.
Figure B.1 shows the modelled network. A is the ingress node and B is Figure B.1 shows the modelled network. A is the ingress node and B is
the egress node. the egress node.
A --- B A --- B
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12. References 12. References
A later version will distinguish normative and informative A later version will distinguish normative and informative
references. references.
[CL-DEPLOY] B. Briscoe, P. Eardley, D. Songhurst, F. Le Faucheur, [CL-DEPLOY] B. Briscoe, P. Eardley, D. Songhurst, F. Le Faucheur,
A. Charny, S. Dudley, J. Babiarz, K. Chan, G. A. Charny, S. Dudley, J. Babiarz, K. Chan, G.
Karagiannis, A. Bader. A Deployment Model for Karagiannis, A. Bader. A Deployment Model for
Admission Control over DiffServ using Pre-Congestion Admission Control over DiffServ using Pre-Congestion
Notification, draft-briscoe-tsvwg-cl-architecture- Notification, draft-briscoe-tsvwg-cl-architecture-
03.txt", (work in progress), October 2006
[DCAC] Richard J. Gibbens and Frank P. Kelly "Distributed [DCAC] Richard J. Gibbens and Frank P. Kelly "Distributed
connection acceptance control for a connectionless connection acceptance control for a connectionless
network", In: Proc. International Teletraffic Congress network", In: Proc. International Teletraffic Congress
(ITC16), Edinburgh, pp. 941952 (1999). (ITC16), Edinburgh, pp. 941?952 (1999).
[Floyd] S. Floyd, 'Specifying Alternate Semantics for the [Floyd] S. Floyd, 'Specifying Alternate Semantics for the
Explicit Congestion Notification (ECN) Field', draft- Explicit Congestion Notification (ECN) Field', draft-
floyd-ecn-alternates-00.txt (work in progress), April floyd-ecn-alternates-00.txt (work in progress), April
2005 2005
[GSPa] Karsten (Ed.), Martin "GSP/ECN Technology \& [GSPa] Karsten (Ed.), Martin "GSP/ECN Technology \&
Experiments", Deliverable: 15.3 PtIII, M3I Eu Vth Experiments", Deliverable: 15.3 PtIII, M3I Eu Vth
Framework Project IST-1999-11429, URL: Framework Project IST-1999-11429, URL:
http://www.m3i.org/ (February, 2002) (superseded by http://www.m3i.org/ (February, 2002) (superseded by
[GSP- TR]) [GSP- TR])
[GSP-TR] Martin Karsten and Jens Schmitt, "Admission Control [GSP-TR] Martin Karsten and Jens Schmitt, "Admission Control
Based on Packet Marking and Feedback Signalling -- Based on Packet Marking and Feedback Signalling ?--
Mechanisms, Implementation and Experiments", TU- Mechanisms, Implementation and Experiments", TU-
Darmstadt Technical Report TR-KOM-2002-03, URL: Darmstadt Technical Report TR-KOM-2002-03, URL:
http://www.kom.e-technik.tu- http://www.kom.e-technik.tu-
darmstadt.de/publications/abstracts/KS02-5.html (May, darmstadt.de/publications/abstracts/KS02-5.html (May,
2002) 2002)
[Hovell] P. Hovell, R. Briscoe, G. Corliano, "Guaranteed QoS [Hovell] P. Hovell, R. Briscoe, G. Corliano, "Guaranteed QoS
Synthesis - an example of a scalable core IP quality Synthesis - an example of a scalable core IP quality
of service solution", BT Technology Journal, Vol 23 No of service solution", BT Technology Journal, Vol 23 No
[Re-PCN] B. Briscoe, "Emulating Border Flow Policing using Re- [Re-PCN] B. Briscoe, "Emulating Border Flow Policing using Re-
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Notification Process for Real-Time Traffic', draft- Notification Process for Real-Time Traffic', draft-
babiarz-tsvwg-rtecn-05 Work in Progress, October 2005. babiarz-tsvwg-rtecn-05 Work in Progress, October 2005.
[tsvwg-ml] Discussion on the TSVWG mailing list, Nov/Dec 2005. [tsvwg-ml] Discussion on the TSVWG mailing list, Nov/Dec 2005.
[Westberg] L. Westberg, Z. R. Turanyi, D. Partain, A. Bader, G. [Westberg] L. Westberg, Z. R. Turanyi, D. Partain, A. Bader, G.
Karagiannis, "Load Control of Real-Time Traffic", Karagiannis, "Load Control of Real-Time Traffic",
draft-westberg-loadcntr-04.txt (Work in progress), Dec draft-westberg-loadcntr-04.txt (Work in progress), Dec
2005 2005
[Zhang] J. Zhang, A. Charny, V. Liatsos, F. Le Faucheur,
"Performance Evaluation of CL-PHB Admission and pre-emption
Algorithms", draft-zhang-pcn-performance-evaluation.txt
(Work in progress), October 2005
Authors' Addresses Authors' Addresses
Bob Briscoe Bob Briscoe
BT Research BT Research
B54/77, Sirius House B54/77, Sirius House
Adastral Park Adastral Park
Martlesham Heath Martlesham Heath
Ipswich, Suffolk Ipswich, Suffolk
IP5 3RE IP5 3RE
United Kingdom United Kingdom
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USA USA
Email: smdudley@nortel.com Email: smdudley@nortel.com
Georgios Karagiannis Georgios Karagiannis
University of Twente University of Twente
P.O. BOX 217 P.O. BOX 217
7500 AE Enschede, 7500 AE Enschede,
The Netherlands The Netherlands
EMail: g.karagiannis@ewi.utwente.nl EMail: g.karagiannis@ewi.utwente.nl
Attila Bder Attila Br
attila.bader@ericsson.com attila.bader@ericsson.com
Lars Westberg Lars Westberg
Ericsson AB Ericsson AB
SE-164 80 Stockholm SE-164 80 Stockholm
Sweden Sweden
EMail: Lars.Westberg@ericsson.com EMail: Lars.Westberg@ericsson.com
Intellectual Property Statement Intellectual Property Statement
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