Method and apparatus for planning an ATM network for an area of concentrated demand for transport bandwidth

#This invention relates generally to ATM network planning and, in particular, to a method and apparatus for planning ATM networks for areas of concentrated demand for transport bandwidth.

#ATM network planning involves designing a network equipped to satisfy all customers' traffic requirements, which may include the voice, data, image and video payloads. There are many issues to be considered in network planning. One well-known aspect of the planning process is the determination of the quantity, location and configuration of network access equipment required for the ingress and egress of customer traffic to the network. This process is usually referred to as Network Access Planning. Another well-known aspect is the design of an efficient backbone network for carrying network traffic. This is usually referred to as Network Backbone Planning. The network backbone may serve a metropolitan area or a larger geographical area.

#There are also many performance issues related to ATM network planning, such as network survivability, qualities of service (QoS) and grades of service (GoS). Since all of these factors are interrelated in quite a complex manner, network planning is a complicated process. In order to facilitate the process, computerized tools have been invented to find optimal network design solutions given traffic demand and access switch locations. One such tool is taught in U.S. Pat. No. 5,508,999 which issued on Apr. 16, 1996 to Cox, Jr. et al. This patent teaches a method and system for generating an optimized transition plan for the placement and interconnection of carrier hubs in a local access network. Cox Jr. et al. use a mixed-integer programming for finding an optimal access network design.

#The invention will now be further explained by way of example only, and with reference to the following drawings, wherein:

#FIG. 1 is a schematic diagram of an ATM network configured in a star topology in accordance with the prior art;

#FIG. 2 is a schematic diagram of an ATM network configured in a design in accordance with the invention; and

#Before describing the invention in detail, some important concepts are briefly discussed.

#A node is a central switching office which can terminate different types of customer services. Each node's location is typically represented by its geographical coordinates, such as longitude and latitude, or V & H coordinates (in North America). In order to accommodate the ingress and egress of network traffic, access switches are required at some nodes where the volume of customer traffic is adequate to warrant such switches. Nodes with access switches are referred to as "homes". Hub switches are also used to carry custom traffic through the network and serve as gateways to move customer traffic to other networks, such as a SONET ring. A node with at least one hub switch is referred to as a "hub". Usually a hub switch has a higher capacity than an access switch.

#For areas of concentrated demand for bandwidth, such as metropolitan regions, it is accepted and may be established by proof that the optimal network solution where transport cost is a constant, is a star topology. A prior art star topology is shown in FIG. 1. Nine homes 10 are connected by links 30 to a hub 20 in a prior art star topology network design.