1. Motivation

The Internet is expanding rapidly, this can be observed in several points of view. Quantitatively, the new growing border is the mobile computing [1]. Qualitatively, one goal is to exceed the limits imposed by the best effort model of service used in the Internet, providing mechanisms to obtain Quality of Service (QoS) [2].

A lot of different definitions of QoS exist, within different technical discourse areas. In the computer networking area, QoS defines both a network performance relative to application requirements, and the technology set to enable networks to offer performance guarantees. In a networking shared environment, QoS necessarily refers to resource reservation [3].

The best effort model adopted to the Internet [4], does not guarantee QoS. However, users are requesting the definition of consistent levels of QoS they would like to use. On the other hand, ISPs (Internet Service Providers) are willing to take care of such users requirements, by introducing new mechanisms that implement service differentiation, along with the existent best effort service. Several approaches to bring QoS to the Internet have been proposed in the last years [5], including:

• The Integrated Services Model (IntServ) [6]
• The Differentiated Services Model (DiffServ) [7]
• MPLS (Multiprotocol Label Switching) [8]
• Traffic Engineering [9]
• QoS Routing [10]

These technologies represent partial solutions, within specific layers. We will show that none of them realizes a complete QoS framework, that meets the requirements of the Internet today, and at the same time is flexible enough to be open to new requirements in the future. However, the proposed QoS schemes can be combined, but it is yet not clear how they may coexist in a single architecture. In fact, this can result in a broad range of architectures [11].

2. Project goals

The main goals of the proposed project are:

• Identify advantages and disadvantages of existing approaches.
• Conceptually combine the approaches in order to get a positive synergetic effect [11].
• Identify and define a set of requirements for an architecture which supports the existence of new advanced network applications in the Internet, and satisfies different users and ISPs requirements.
• Develop a model for a new QoS architecture for the Internet. This architecture must be able to adapt to distinct conditions of several applications, users and networks types, within some QoS classification dimensions presented in [12]. To do this it must incorporate characteristics of some existent approaches, mainly the DiffServ and also the InterServ Architectures. It must consider the existence of mobile users as well. We call this architecture "Chameleon", which depicts the capacity to adapt to different environment conditions.
• Validate this architecture, using simulation (with Network Simulator, ns[13]), but also using analytical modeling and real measurements (there are some DiffServ implementations that can be adapted to represent the functionality of this architecture [14, 15, 16, 17]).
• Implement a prototype in companies that currently have interest in the Internet QoS subject. Currently, two companies demonstrated interest, one in Germany (work with multimedia applications in the Internet) and another in Brazil (a telephone carrier that in the future will be a Internet backbone provider).

3. References

[1]	Fasbender, A., Any Network, Any Terminal, Anywhere, IEEE Personal Communications, April 1999.
[2]	Ferguson, P. & Huston, G., Quality of Service: Delivering QoS on the Internet and in Corporate Networks, John Wiley & Sons, 1998.
[3]	Teltelman, B. & Hanss, T., QoS Requirements for Internet2, Internet2 QoS Work Group Draft, April 1998.
[4]	Leiner, B. M. et al., The Past and Future History of the Internet, Communications of the ACM, February 1997.
[5]	Xiao, X. & Ni, L. M., Internet QoS: A Big Picture, IEEE Network, March/April 1999.
[6]	Braden, R., Clark, D. & Shenker, S., Integrated Services in the Internet Architecture: an Overview, IETF RFC 1633, June 1994.
[7]	Black, D. et. al., An Architecture for Differentiated Services, Internet RFC 2475, December 1998.
[8]	Rosen, E. et al., Multiprotocol Label Switching Architecture, Internet Draft, <draft-ietf-mpls-arch-05.txt>, April 1999.
[9]	Awduche, D. et al., Requirements for Traffic Engineering over MPLS, Internet Draft, <draft-ietf-mpls-traffic-eng-01.txt>, June 1999.
[10]	Crawley, E. et al., A Framework for QoS-based Routing in the Internet, Internet RFC 2386, August 1998.
[11]	Stardust.com, Inc., QoS Protocols & Architectures, White Paper, July 1999.
[12]	Bradner, S. et al., Internet Protocol Quality of Service Problem Statement, IETF Internet Draft, <draft-bradner-qos-problem-00.txt>, Sept. 1997.
[13]	VINT Project, Network Simulator – Version 2, Lawrence Berkeley Laboratory, http://www-mash.cs.berkeley.edu/ns, 1999
[14]	Terzis, A., et. al., A Prototype Implementation of the Two-Tier Architecture for Differentiated Services, RTAS99, 1999, Vancouver, Canada, http://irl.cs.ucla.edu/twotier.
[15]	Cho, K., A Framework for Alternate Queueing: Towards Traffic Management by PC-UNIX Based Routers, USENIX98, June 1998, http://www.csl.sony.co.jp/person/kjc/programs.html
[16]	Almesberger, W., Salim, J. H. & Kuznetsov, A., Differentiated Services on Linux, IETF Internet Draft <draft-almesberger-wajhak-diffserv-linux-01.txt>, June 1999, http://lrcwww.epfl.ch/linux-diffserv
[17]	Bless, R. & Wehrle, K., Evaluation of Differentiated Services using an Implementation under Linux, IFIP & IEEE IWQOS’99, June 1999, http://www.telematik.informatik.uni-karlsruhe.de/forschung/diffserv/KIDS/index.htm

 

4. Author’s Adress

Departamento de Informática (Sala B07)

Universidade Federal de Pernambuco

Caixa Postal 7851, Cidade Universitária

Recife PE 50732-970 Brazil

Tel: +55-81 271-8430 (Ext: 3067), Fax: +55-81 271-8438

e-mail: cak@di.ufpe.br

Prof. Djamel Sadok Ph.D. (head of research group)

Departamento de Informática (Sala C20)

Universidade Federal de Pernambuco

Caixa Postal 7851, Cidade Universitária

Recife PE 50732-970 Brazil

Tel: +55-81 271-8430 (Ext: 3301), Fax: +55-81 271-8438

e-mail: jamel@di.ufpe.br