Differentiated Services

• Introduction
• IETF RFCs
• IETF Drafts
• Other Drafts
• Papers
• Related Papers
• ns Implementation

Introduction

New multimedia applications need real-time performance guarantees such as bounded delay and minimum throughput. The current Internet does not support these QoS parameters and it is a real challenge to integrate them in the existing architecture. The DiffServ WG is working on providing a simple schema to support various types of applications by differentiating classes of service for Internet traffic.

The differentiated services architecture proposes the use of a well-defined set of building blocks from which a variety of services may be built. In this architecture, each packet carries an information (DS byte) used by each hop to give it a particular forwarding treatment.

The major goals of the DiffServ WG are to standardize the layout of the DS byte and to assign specific forwarding treatment, called per-hop behavior, to a certain number of patterns of the DS byte, e.g. the forwarding treatment received by best-effort traffic.

Differentiated service mechanisms allow network providers to allocate different levels of service to different users of the Internet and investigations are being done on mechanisms such as traffic meters, shapers/droppers, packet markers to be used at the boundaries of the network.

Many discussions happens on the group's mailing list. Subscription requests for the DiffServ mailing list should be sent to majordomo@baynetworks.com with the line "subscribe diff-serv" in the message body. The group's mailing list itself is at diff-serv@baynetworks.com.

The DiffServ official web page is at www.ietf.org/html.charters/diffserv-charter.html.

IETF RFCs

• "Definition of Differentiated Services Per Domain Behaviors and Rules for their Specification"
  (RFC3086), April 2001.
• "A Framework for Integrated Services Operation over Diffserv Networks"
  (RFC2998), November 2000.
• "A Two Rate Three Color Marker"
  (RFC2698), September, 1999.
• "A Single Rate Three Color Marker"
  (RFC2697), September, 1999.
• "A Two-bit Differentiated Services Architecture for the Internet"
  (RFC2638), July, 1999.
• "Assured Forwarding PHB Group"
  (RFC2597), June, 1999.
• "An Expedited Forwarding PHB"
  (RFC2598), June, 1999.
• "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers"
  (RFC2474), December, 1998.
• "An Architecture for Differentiated Services"
  (RFC2475), December, 1998.

IETF Drafts

• "Supplemental Information for the New Definition of the EF PHB"
  (draft-ietf-diffserv-ef-supplemental-01), February, 2001.
• "An Assured Rate Per-Domain Behaviour for Differentiated Services"
  (draft-ietf-diffserv-pdb-ar-00), June, 2001.
• "A Bulk Handling Per-Domain Behavior for Differentiated Services"
  (draft-ietf-diffserv-pdb-bh-02), January, 2001.
• "A revised expression of the Expedited Forwarding PHB"
  (draft-ietf-diffserv-efresolve-00), November, 2000.
• "Service Level Specification Semantics, Parameters and negotiation requirements"
  (draft-tequila-diffserv-sls-00), July, 2000.
• "Definition of Differentiated Services Behavior Aggregates and Rules for their Specification"
  (draft-ietf-diffserv-ba-def-01), February, 2000.
• "A Framework for Differentiated Services"
  (draft-ietf-diffserv-framework-01), October, 1998.

Others Drafts

• "IP Multicast in Differentiated Services Networks"
  (draft-bless-diffserv-multicast-00.txt), September, 1999.
• "A Lower Than Best-Effort Per-Hop Behavior"
  (draft-bless-diffserv-lbe-phb-00.txt), September, 1999.
• "Usefullness of three drop precedences in Assured Forwarding service"
  (draft-elloumi-diffserv-threevstwo-00), July, 1999.
• "A rate adaptive shaper for differentiated services"
  (draft-bonaventure-diffserv-rashaper-00), June, 1999.
• "A Fair Marker"
  (draft-kim-fairmarker-diffserv-00), April, 1999.
• "A Two Rate Three Color Marker"
  (draft-heinanen-diffserv-trtcm-01), May, 1999.
• "A Single Rate Three Color Marker"
  (draft-heinanen-diffserv-srtcm-01), May, 1999.
• "A Three Color Marker"
  (draft-heinanen-diffserv-tcm-01), February, 1999.
• "TCP-Friendly Traffic Conditioners for Differentiated Services"
  (draft-azeem-tcpfriendly-diffserv-00), February, 1999.
• "Voice over Differentiated Services"
  (draft-naser-voice-diffserv-eval-00), December, 1998.
• "Requirements of Diff-serv Boundary Routers"
  (draft-bernet-diffedge-01), November, 1998.
• "Preliminary Simulation Evaluation of an Assured Service"
  (draft-ibanez-assured-eval-00), August, 1998.
• "A One-bit Feedback Enhanced Differentiated Services Architecture"
  (draft-shivkuma-ecn-diffserv-00), March 1998.
• "User-Share Differentiation (USD) Scalable bandwidth allocation for differentiated services"
  (draft-wang-diff-serv-usd-00), November 1997.
• "An Approach to Service Allocation in the Internet"
  (draft-clark-diff-svc-alloc-00), July 1997.

Papers

• Evaluating Fairness in the Aggregated Traffic Marking
  I.B.H. Alves, J.F. Rezende, L.F.M. Moraes, Universidade Federal do Rio de Janeiro
  to appear in Proc. of the IEEE Global Telecommunications Conference - GLOBECOM'00, November 2000.
• On Achievable Service Differentiation with Token Bucket Marking for TCP
  S. Sahu, P. Nain, D. Towsley, C. Diot, V. Firoiu, Univertsity of Massachusetts at Amberst, INRIA Sophia Antipolis, Sprint ATL, and Nortel Networks
  ACM SIGMETRICS 2000, August 2000.
• Proportional Differentiated Services, Part II: Loss Rate Differentiation and Packet Dropping
  C. Dovrolis and P. Ramanathan, Univertsity of Wisconsin-Madison
  Proc. of the IEEE/IFIP Eighth International Workshop on Quality of Service - IWQoS'2000, June 2000.
• A TCP-Friendly Traffic Marker for IP Differentiated Services
  A. Feroz, A. Rao, and S. Kalyanaraman, Rensselaer Polytechnic Institute
  Proc. of the IEEE/IFIP Eighth International Workshop on Quality of Service - IWQoS'2000, June 2000.
• Dynamic Edge Provisioning for Core IP Networks
  R. R.-F. Liao and A. T. Campbell, Columbia University
  Proc. of the IEEE/IFIP Eighth International Workshop on Quality of Service - IWQoS'2000, June 2000.
• Toward a Theory of Differentiated Services
  H. Ren and K. Park, Purdue University
  Proc. of the IEEE/IFIP Eighth International Workshop on Quality of Service - IWQoS'2000, June 2000.
• A Fair Traffic Conditioner for the Assured Service in a Differentiated Services Internet
  I. Andrikopoulos, L. Wood, and G. Pavlou, Centre for Communication Systems Research, University of Surrey
  Proc. of the IEEE International Conference on Communications - ICC'99, June 2000.
• Content-Based Packet Video Forwarding Mechanism in Differentiated Services Networks
  Jitae Shin, Jong-Won Kim, and C.-C. Jay Kuo, University of Southern California
  Proc. of the Packet Video Workshop'2000, May 2000.
• Peering and Provisioning of Differentiated Internet Services
  N. Semret, R. R.-F. Liao, A. T. Campbell, A. A. Lazar, University of California at Los Angeles, Columbia University
  Proc. of the IEEE INFOCOM'2000, March 2000.
• Competitive Queue Policies for Differentiated Services
  W. Aiello, Y. Mansour, S. Rajagopolan, and A. Rosen, AT&T Research, Tel-Aviv University, Telcordia Technologies, and University of Toronto
  Proc. of the IEEE INFOCOM'2000, March 2000.
• Delay Differentiation and Adaptation in Core Stateless Networks
  T. Nandagopal, N. Venkitaraman, R. Sivakumar, and V. Bharghavan, University of Illinois at Urbana-Champaign
  Proc. of the IEEE INFOCOM'2000, March 2000.
• Assured Service Evaluation
  J. F. Rezende, Universidade Federal do Rio de Janeiro
  Proc. of the IEEE Global Telecommunications Conference - GLOBECOM'99, p. 100-104, December 1999.
• Towards a Differentiated Services Support for Voice Traffic
  A. Ziviani, J. F. Rezende, and O. C. M. B. Duarte, Universidade Federal do Rio de Janeiro
  Proc. of the IEEE Global Telecommunications Conference - GLOBECOM'99, p. 59-63, December 1999.
• RED+ Gateways for Identification and Discrimination of Unfriendly Best-Effort Flows in the Internet
  T. Ziegler, S. Fdida, and U. Hofmann, Université Pierre et Marie Curie (Paris, France), School for Telecommunications (Salzburz, Austria)
  IFIP Fifth International Conference on Broadband Communications - BC'99, November 1999.
• A Case for Relative Differentiated Services and the Proportional Differentiation Model
  C. Dovrolis and P. Ramanathan, Univertsity of Wisconsin-Madison
  IEEE Network, vol. 13, no. 5, September/October 1999.
• Internet2 QBone - Building a Testbed for Differentiated Services
  B. Teitelbaum, S. Hares, L. Dunn, V. Narayan, R. Neilson, and F. Reichmeyer, Internet2, Merit Network, Cisco Systems, NASA, British Columbia Institute of Technology, and IPHighway
  IEEE Network, vol. 13, no. 5, September/October 1999.
• Providing Internet Access: What we learn from the INDEX Trial
  R. J. Edell and P. P. Varaiya, Univertsity of California, Berkeley
  IEEE Network, vol. 13, no. 5, September/October 1999.
• Providing Guaranteed Services Without Per Flow Management
  I. Stoica, H. Zhang, Carnegie Mellon University
  Proc. of the ACM SIGCOMM'99, September 1999.
• A Flexible Model for Resource Management in Virtual Private Networks
  N. G. Duffield, P. Goyal, A. Greenberg, P. Miahra, K. K. Ramakriahnan, J. F. van der Merwe, AT&T Labs-Research
  Proc. of the ACM SIGCOMM'99, September 1999.
• Proportional Differentiated Services: Delay Differentiation and Packet Scheduling
  C. Dovrolis, D. Stiliadis, and P. Ramanathan, University of Wisconsin, Bell Laboratories
  Proc. of the ACM SIGCOMM'99, September 1999.
• Performance Comparison of Different Class-and-Drop Treatment of Data and Acknowledgements in DiffServ IP Networs
  S. Köhler and U. Schäfer, University of Wurzburg (Germany)
  Technical report no. 237, August 1999.
• Reasons not to deploy RED
  M. May, J. Bolot, C. Diot, and B. Lyles, INRIA and Sprint Labs
  Proc. of the IEEE/IFIP International Workshop on Quality of Service - IWQoS'99, June 1999.
• Paris Metro Pricing: The Minimalist Differentiated Services Solution
  Andrew Odlyzko, AT&T Labs - Research
  Proc. of the IEEE/IFIP International Workshop on Quality of Service - IWQoS'99, June 1999.
• Fairness of Assured Service
  F. Baumgartner, T. Braun, C. Siebel, University of Berne and Deutsche Telekom AG
  Proc. of the European Simulation Multiconference - ESM'99, June 1999.
• Relative Differentiated Services in the Internet: Issues and Mechanisms
  C. Dovrolis and D. Stiliadis, Univertsity of Wisconsin-Madison
  ACM SIGMETRICS 1999, May 1999.
• Internet QoS: the Big Picture
  X. Xiao, L. M. Li, Michigan State University
  IEEE Network, vol. 13, no. 2, pp. 1-13, March/April 1999.
• Peering and Provisioning of Differentiated Internet Services
  N. Semret, R. R.-F. Liao, A. T. Campbell, and A. A. Lazar, Columbia University
  Technical Report, March 1999.
• The Cost of QoS Support in Edge Devices: An Experimental Study
  R. Guérin, L. Li, S. Nadas, P. Pan, V. Peris, IBM
  Proc. of the IEEE INFOCOM'99, March 1999.
• A Quantitative Study of Differentiated Services for the Internet
  S. Sahu, D. Towsley, J. Kurose, University of Massachusetts
  UMass CMPSCI Technical Report 99-09
• Market Pricing of Differentiated Internet Services
  N. Semret, R. R.-F. Liao, A. T. Campbell, A. A. Lazar, Columbia University
  Technical Report CU/CTR/TR 503-98-37, December 1998.
• Differentiated Services: A New Approach for Quality in the Internet
  F. Baumgartner, T. Braun, P. Habegger, University of Berne
  Proc. of the 8th IFIP Conference on High Performance Networking - HPN'98, September 1998.
• Explicit Allocation of Best Effort Packet Delivery Service
  David D. Clark and Wenjia Fang, MIT Lab for Computer Science
  IEEE/ACM Transactions on Networking, vol. 6, no. 4, pp. 362-373, August 1998.
• Adaptive Packet Marking for Providing Differentiated Services in the Internet
  W. Feng, D. Kandlur, D. Saha, and K. Shin, University of Michigan and IBM
  Technical Report U. Michigan CSE-TR-347-97 or IBM Research Report RC 21013, October 1997.
• Understanding TCP Dynamics in an Integrated Services Internet
  W. Feng, D. Kandlur, D. Saha, and K. Shin, University of Michigan and IBM
  Proc. of the NOSDAV'97, May 1997.
• A Comparative Study of Schemes for Differentiated Services
  A. Basu, Z. Wang, Bell Laboratories, Lucent Technologies
  
• Combining Sender and Receiver Payments in the Internet
  David D. Clark, MIT Lab for Computer Science
  
• 1-Bit Schemes for Service Discrimination in the Internet: Analysis and Evaluation
  Martin May, Jean-Chrysotome Bolot, Christophe Diot, Alain Jean-Marie, Inria
  
• Scalable Resource Reservation for the Internet
  Werner Almesberger, Jean-Yves Le Boudec, Tiziana Ferrari, EPFL
  

Related Papers

• The Impact of Multicast Layering on Network Fairness
  Dan Rubenstein, Jim Kurose, and Don Towsley, Univertsity of Massachusetts at Amberst
  Proc. of ACM SIGCOMM'99, September 1999.
• Core-Stateless Fair Queueing: Achieving Approximately Fair Bandwidth Allocations in High Speed Networks
  I. Stoica, S. Shenker, and H. Zhang, Carnegie Mellon University and Xerox PARC
  Proc. of ACM SIGCOMM'98, September 1998.
• The Macroscopic Behavior of the TCP Congestion Avoidance Algorithm
  M. Mathis, J. Semke, J. Mahdavi, and T. Ott, Polytechnic University
  IEEE Journal on Selected Areas in Communications, volume 15, pp.bg 867-879, June 1997.
• Design of a Generalized Priority Queue Manager for ATM Switches
  H. J. Chao, H. Cheng, Y-R. Jeng, and D. Jeong, Pittsburgh Supercomputer Center and BellCore
  Computer Communication Review, volume 27, number 3, July 1997.
• Simulation-based Comparisons of Tahoe, Reno, and SACK TCP
  Kevin Fall and Sally Floyd, Lawrence Berkeley National Laboratory
  Computer Communication Review, volume 26, number 3, July 1996.
• Congestion Avoidance and Control
  Van Jacobson and Michael J. Karels, Lawrence Berkeley Laboratory and Univertsity of California at Berkeley
  Proc. of ACM SIGCOMM'88, August 1988.

ns Implementation

ns (network simulator) is a event-driven simulator developed at Berkeley. It has as front-end an OTcl interpreter and it is written in C++. Extensions to ns has been done to accomodate differentiated service architecture elements such as classifiers, markers, droppers/shapers and RIO buffer management. These extensions are currently implemented in ns version 2.1b5 using a Linux box. We are currently preparing a documentation to the use of this architecture. As soon it is finished the implementation will be publicly available at this page.