Broadband Packet Switching Technologies: A Practical Guide to ATM Switches and IP Routers

CHAPTER 1

INTRODUCTION

The scalable and distributed nature of the Internet continuously contributes to a wild and rapid growth of its population, including the number of users, hosts, links, and emerging applications. The great success of the Internet thus leads to exponential increases in traffic volumes, stimulating an unprecedented demand for the capacity of the core network.

Network providers therefore face the need of providing a new network infrastructure that can support the growth of traffic in the core network. Advances in fiber throughput and optical transmission technologies have enabled operators to deploy capacity in a dramatic fashion. However, the advancement in packet switch/router technologies is rather slow, so that it is still not able to keep pace with the increase in link transmission speed.

Dense-wavelength-division-multiplexing (DWDM) equipment is installed on each end of the optical fiber to multiplex wavelengths (i.e., channels) over a single fiber. For example, a 128-channel OC-192 (10 Gbit/s) DWDM system can multiplex the signals to achieve a total capacity of 1.2 Tbit/s. Several vendors are expected to enter trials for wide area DWDM networks that support OC-768 (40 Gbit/s) for each channel in the near future.

Another advanced optical technology that is ...