draft-ietf-diffserv-pdb-ar-00.txt   draft-ietf-diffserv-pdb-ar-01.txt 
INTERNET DRAFT N. Seddigh INTERNET DRAFT N. Seddigh
Internet Engineering Task Force B. Nandy Internet Engineering Task Force B. Nandy
Differentiated Services Working Group Nortel Networks Differentiated Services Working Group Tropic Networks
Expires August, 2001 J. Heinanen Expires January, 2002 J. Heinanen
Telia Finland Song Networks
February, 2001 July, 2001
An Assured Rate Per-Domain Behaviour for Differentiated Services An Assured Rate Per-Domain Behaviour for Differentiated Services
<draft-ietf-diffserv-pdb-ar-00.txt> <draft-ietf-diffserv-pdb-ar-01.txt>
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. 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.
skipping to change at page 6, line 23 skipping to change at page 6, line 23
the egress nodes. the egress nodes.
It is easier for a provider to demonstrate conformance with the SLS It is easier for a provider to demonstrate conformance with the SLS
in the one-to-one service since all measurements can be performed at in the one-to-one service since all measurements can be performed at
a single egress point. In the case of a one-to-any service, a single egress point. In the case of a one-to-any service,
measurements need to be performed at all egress nodes where packets measurements need to be performed at all egress nodes where packets
are sent from an ingress node during the measurement interval. These are sent from an ingress node during the measurement interval. These
measurements then have to be correlated to determine the cumulative measurements then have to be correlated to determine the cumulative
bandwidth of the aggregate as it exits the domain. bandwidth of the aggregate as it exits the domain.
The AR definition allows coupling of the PDB parameters with Most of the previous portion of this document discussed deployment of
probabilities for statistical assurance. For example, the SLS MAY the AR PDB in the context of an IP routed network. It is also
specify a Y% assurance for the CIR (with CBS/T1) when sampled every X possible to deploy the AR PDB in other networks - for example, in an
minutes. MPLS network which supports the Diffserv architecture and mechanisms
[DIFFMPLS]. In a Diffserv-enabled MPLS network with dedicated,
constraint based LSPs, the AR PDB could be deployed using either E-
LSPs or L-LSPs. In such a network, traffic engineering can be used in
conjunction with per-LSP admission control mechanisms to provide AR
PDB-based services that are quantitative in nature.
9.0 Acknowledgements In such a network, the AR PDB could be used as the basis for an SLS
that includes additional parameters such as statistical assurance
probabilities or packet drop assurance. As an example of the former,
the SLS MAY specify a Y% assurance for the CIR (with CBS/T1) when
sampled every X minutes. As an example of the latter, the SLS MAY
specify a CIR (with CBS/T1) and a Y% drop ratio for AR PDB traffic
for a particular customer.
9.0 Simulation Summary
There have been a number of simulation and emulation studies of
involving PDBs that essentially provide similar behaviour to the AR
PDB. In this section, we briefly summarize some of those studies.
The primary aim is to show that with the deployment of the required
mechanisms, in general, it is possible to provide rate assurance over
a time period. Some of the studies also point to suitable
provisioning or subscription levels for network links in order to
support such a PDB.
In [TON98], the authors perform simulations that show how AR PDB-like
behaviour can be realized in a simple topology utilizing RIO in
conjunction with a sliding window policer. This set of simulations
showed that the rate for individual TCP or UDP flows can be assured.
In [YEOM], the authors perform simulation tests involving aggregates
of TCP flows with different RTTs. The topology in this case was a
dumbell topology. The results indicated that for the utilized
topology, the aggregate rate could be assured with a link
subscription level of as high as 80%.
In [REZENDE], the authors perform simulations with more complicated
topologies involving flow merge and split points, congestion in both
directions of a link. In this set of experiments, individual flows
had their assured rates. The simulations showed that for link
provisioning levels of 40%, the network could assure the rates for
the individual flows.
In [HPN2000], the authors perform simulations involving aggregates of
TCP and UDP flows. It is observed that if UDP and TCP in-profile
packets are marked green, the aggregates achieve their CIR. In
another simulation, different flow aggregates with different CIRs,
share the same bottleneck link with total allocated bandwidth
constituting 40% and 80% of link capacity. It is observed that for
the 40% case, the CIR for the different aggregates are always
achieved. However, in the 80% case, the CIR for a few of the
aggregates are not achieved.
10.0 Acknowledgements
The authors would like to thank the following individuals for their The authors would like to thank the following individuals for their
helpful comments and suggestions: Brian Carpenter, Shahram Davari and helpful comments and suggestions: Marcus Brunner, Brian Carpenter,
Alper Demir. Shahram Davari and Alper Demir.
10.0 References 10.0 References
[TON98] D.D. Clark, W. Fang, "Explicit Allocation of Best Effort [TON98] D.D. Clark, W. Fang, "Explicit Allocation of Best Effort
Packet Delivery Service", IEEE/ACM Transactions on Networking, Packet Delivery Service", IEEE/ACM Transactions on Networking,
August 1998, Vol 6. No. 4, pp. 362-373. August 1998, Vol 6. No. 4, pp. 362-373.
[RFC2474] K. Nichols, S. Blake, F. Baker, and D. Black, "Definition of [RFC2474] K. Nichols, S. Blake, F. Baker, and D. Black, "Definition of
the Differentiated Services Field (DS Field) in the IPv4 and IPv6 the Differentiated Services Field (DS Field) in the IPv4 and IPv6
Headers", Internet RFC 2474, December 1998. Headers", Internet RFC 2474, December 1998.
[RFC2475] D. Black, S. Blake, M. Carlson, E. Davies, Z. Wang, and [RFC2475] D. Black, S. Blake, M. Carlson, E. Davies, Z. Wang, and
W. Weiss, "An Architecture for Differentiated Services", W. Weiss, "An Architecture for Differentiated Services",
Internet RFC 2475, December 1998. Internet RFC 2475, December 1998.
[AFPHB] J. Heinanen, F. Baker, W. Weiss, J. Wroclawski, [AFPHB] J. Heinanen, F. Baker, W. Weiss, J. Wroclawski,
[PDBDEF] Nichols K and Carpenter B, "Definition of Differentiated [YEOM] Yeom I and Reddy N, "Impact of Marking Strategy for Aggregated
Services Per Domain Behaviours and Rules for their Flows in a Differentiated Services Network", Proceedings of
Specification", Internet Draft, October 2000
[SRTCM] J. Heinanen and R. Guerin, "A Single Rate Three Colour Marker", [SRTCM] J. Heinanen and R. Guerin, "A Single Rate Three Colour Marker",
Internet RFC 2697, September 1999 Internet RFC 2697, September 1999
[TRTCM] J. Heinanen and R. Guerin, "A Two Rate Three Colour Marker", [TRTCM] J. Heinanen and R. Guerin, "A Two Rate Three Colour Marker",
Internet RFC 2698, September 1999 Internet RFC 2698, September 1999
[REZENDE] J Rezende, "Assured Service Evaluation", Proceedings of
GLOBECOM 99, Rio De Janiero, December 1999
[TSWTCM] W. Fang, N. Seddigh and B. Nandy, "A Time Sliding Window [TSWTCM] W. Fang, N. Seddigh and B. Nandy, "A Time Sliding Window
[HPN2000] Nandy B, Seddigh N, Pieda P and Ethridge J, "Intelligent Traffic
Conditioners for Assured Forwarding Based Differentiated Services
Networks", Proceedings of HPN 2000, Paris, June 2000.
[PDBDEF] Nichols K and Carpenter B, "Definition of Differentiated
Services Per Domain Behaviours and Rules for their
Specification", Internet Draft, October 2000
[DIFFMPLS] Le Faucher et al, "MPLS Support of Differentiated Services",
9.0 Author Addresses 9.0 Author Addresses
Nabil Seddigh Nabil Seddigh
Nortel Networks, Tropic Networks,
3500 Carling Ave 135 Michael Cowpland Drive
Ottawa, ON, K2H 8E9 Kanata, ON, K2M 2E9
Canada Canada
Email: nseddigh@nortelnetworks.com Email: nseddigh@tropicnetworks.com
Biswajit Nandy Biswajit Nandy
Nortel Networks, Tropic Networks,
3500 Carling Ave 135 Michael Cowpland Drive
Ottawa, ON, K2H 8E9 Kanata, ON, K2M 2E9
Canada Canada
Email: bnandy@nortelnetworks.com Email: bnandy@tropicnetworks.com
Juha Heinanen Juha Heinanen
Telia Finland, Song Networks, Inc.
Email: jh@telia.fi Hallituskatu 16
33200 Tampere
Finland
Email: juha.heinanen@mail.com
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