Communication networks are facing new challenges, and as a response, the Next Generation Networks (NGNs) are being developed under pressure from new services and enabled by technology innovation. The switching fabrics play a very important role in the evolution of communication networks and services. A new and efficient switching fabric can control and manage the resources in the NGNs. The purpose of this paper is to review a popular category of switching fabrics NGNs—Banyan architecture-based switching fabrics suitable for NGNs, in terms of their architecture and performance evaluation under various traffic conditions.

Increasing demand for diverse network services and rapid change in technologies for microelectronics, software, photonics and wireless are transforming the conventional nature of communication networks. Besides technical factors, change in regulations, traffic growth and market forces like cost reduction and subscriber growth are also driving this transformation. The net effect of these driving forces has led to a set of new requirements that are placed on the communication networks. These requirements result in the emergence of a new generation of network architectures. The emerging future network, also known as Next Generation Network (NGN), will become a cornerstone of the information society of tomorrow. It is expected that NGNs will be larger than the world's telephone network and more revolutionary than the Internet.

NGNs will be more efficient to build and less costly to operate. They will be ubiquitous and will have performance that far exceeds that of today's many networks. To fulfill the requirements of emerging high-speed services, the NGN architecture is heading towards an integrated and converged packet network. The core network of the NGNs provide the interconnect mechanism for various access networks, as shown in Figure 1 (Matthew, 2002). Different multicast/broadcast services, such as multimedia services, video-on-demand, video-conferencing, music-on-demand, Teleconferencing and distributed data processing, and other similar services should be supported on NGNs. The NGNs should also have a provision for many new and unforeseen applications (Matthew, 2002). The NGNs have to transport all kinds of information, ranging from voice to high quality video. These services have different requirements in terms of bit rate, behavior in time, semantic transparency (packet loss rate and bit error rate) and time transparency (delay and delay jitter) (Batcher, 1968). Further, there exists a need to handle constant bit rate and variable bit rate at the same time. In order to provide good quality of service with this complex requirement set, the performance, reliability and integrity of the networks need to be improved.

Telecommunications Journal, Banyan Network, Deflection-Routed, Fault-Tolerant, Markov Chain, Multistage Interconnection Networks, Multicast, Next Generation Network, Performance Evaluation, Switching Fabric, Self-Routing Switch, Next Generation Network, NGN, Technology Innovation, Multiprotocol Label Switches, MPLS, Banyan Architecture, First in First Out, FIFO.