The group on “Performance of Communication Systems” started, as a Task Force, in 1993 at the Fifth International Conference on Data Communication Systems and their Performance (Raleigh, NC, USA, 26- 28 October, 1993), after an in-depth discussion in TC6 about the need of a working group on the performance of communication systems. Indeed the performance evaluation has a relevant role in communication systems design and configuration by providing effective tools for investigating the quality of service provided by a communication system. Therefore, the history of communication systems research is tightly coupled with the performance evaluation. Brilliant examples range from A.K. Erlang queuing-system studies applied to dimensioning the telephone network, to L. Kleinrock works applying queuing theory to investigate the packet switching technology, which is the foundation of the Internet.

WG 6.3 was formalized as a Working Group in 1994. Harry Perros (who led the Task Force) was the first chairmen, and Yutaka Takahashi was the co-chairman. The WG activities started with the first WG 6.3 workshop in St Thomas, Virgin Islands (January 1995). The WG 6.3 flagship conference “Performance of Communication Systems” was organized three times: Raleigh (NC, USA, October 1993), Istanbul, (Turkey, October 1995), and Lund (Sweden, May 25-28, 1998). In-between the flagship conferences, the working group organized the WG 6.3 workshops at St. Thomas (January 1995) and Crete (September 1999). In year 2000, for the initiative of Harry Perros and Guy Pujolle, the WG 6.3 flagship conference was combined with the flagship conferences of WGs 6.2 and 6.4 to form a stronger conference series: the bi-annual Networking conference series. Networking 2000 (Paris, May 2000) was the first event in this series followed by Networking 2002 (Pisa, May 2002), when WG 6.8 stared its co-sponsorship, and Networking 2004 (Athens, May 2004). Since 2005 the Networking conference is organized on an annual basis.

In 2003, Ioannis Stavrakakis became the second chairman of the working group, and Marco Conti replaced him in 2009. Since January 2015, the chairman is Andrea Passarella.
Today, the working group has more than 50 members worldwide, covering different aspects in the performance evaluation of communication systems. Networking is the flagship conference of the working group. In addition, WG 6.3 supports several other workshops and conferences related to the performance evaluation of communications systems. Details on the WG 6.3 members, current and past activities can be found in the working group website: http://cnd.iit.cnr.it/ifipwg63.

The WG is aimed at promoting the development and use of performance evaluation techniques and methods for studying and optimizing existing and emerging computer communication systems. Both measurement and modelling techniques are within the scope of the working group. The former are directly applied to a real communication system, or a system prototype. The advantage of measurement techniques is that real-system estimates are obtained. However, measurement techniques do have their disadvantages; the major one is the need of a functioning system, and this is generally very expensive. Using a model on the other hand allows us to study the system in each phase of its life cycle (design, development, and modifications) to verify the effectiveness of a solution before it is implemented thus reducing the deployment costs and/or the risks to have performance problems into an operational system. Depending on the problem complexity and the required accuracy of the study, analytical or simulation models can be applied. Analytical models, generally, provide exact and effective solutions for simple model, but only approximate solutions are possible for complex systems. When analytical models are mathematically untractable (or too approximate), simulation modelling constitutes a valid, but expensive alternative. Hybrid approaches, involving both analytical and simulation techniques are therefore a possible compromise. Since its creation, the WG has promoted the use of the above performance evaluation techniques to studying existing and emerging communication technologies (from broadband wired networks of early nineties to pervasive and mobile social networks of today), and to investigating how the technological evolution has changed the structure and organization of communication systems and services -- from circuit switched networks tailored on voice traffic, to highly decentralized, IP-based, multi-service networks.