TABLE OF CONTENTS GMPLS provides a common control plane for managing a variety of different network technologies and for leveraging those technologies to enable high-function services across the network. To give some context for the chapters that follow, this chapter introduces the concept of a transport network and gives an overview of the different transport network technologies such as Time Division Multiplexing (TDM) and Wavelength Division Multiplexing (WDM).
The chapter also summarizes some of the popular network topologies (ring, mesh, mixed, etc.) and goes on to describe how the software of a Transport Network Element (TNE) can be broken into three major planes the data plane, the control plane, and the management plane and provides a general overview of each of the planes.
The International Telecommunications Union (ITU) defines transport as "the functional process of transferring information between different locations" in its Recommendation G.805 entitled Generic functional architecture of transport networks. This definition may be a little too loose for our purposes, because it would make all networks of any variety into transport networks.
A refinement of the transport concept comes within the same Recommendation, where a transport network is defined as "the functional resources of the network which conveys user information between locations." The key addition in this definition is the reference to the fact that the information that is transferred is user information. This places a clear layering structure on the network, with islands of the user network connected by one or more transport...
