AT&T Labs Research — Leading Invention, Driving Innovation

A method and apparatus for the estimation of traffic matrices in a network are disclosed. Mechanisms are disclosed for measuring traffic volume from a plurality of ingress points to a plurality of egress points in a large scanl network, such as an IP backbone network. The traffic matrix is advantageously inferred from widely available link load measurements such as SNMP data.

An apparatus and method for designing a network are disclosed. The network is designed wherein nodes originate and terminate traffic to keep delay related to node-to-node delay-sensitive communication below a specified threshold. The method obtains an initial network topology including links and traffic routing based on a volume of traffic, allocates a maximum delay to each link in the network topology in proportion to the square root of an imputed cost for each link, sizes a bandwidth required for each link based on a current traffic routing and at least one of a maximum delay allocated to the link, determines link lengths and reroutes traffic according to shortest paths with respect to the determined link lengths.

A method and apparatus for designing a network that supports an integrated environment for all types of applications while satisfying individual performance requirements. An initial network topology is retrieved or created, including links and traffic routing based on a volume of traffic. A maximum delay is then allocated to each link in the network topology so that the delay limits on node-to-node communication are satisfied. Further, a bandwidth required for each link is sized based on a current traffic routing as well as a maximum delay allocated to the link and total link utilization. Link lengths are then determined, based on marginal costs, and traffic is rerouted according to shortest paths with respect to the link lengths.

A method is provided for designing a hierarchical architecture for a synchronous optical network (SONET) given a plurality of demand nodes at which communications traffic originates and at least one destination node at which the communications traffic is collected for transmission to a switch. The method includes the steps of: (a) dividing the plurality of demand nodes into distinct groups of demand nodes; (b) selecting at least one node for each group to serve as a ring hub for connection to a backbone ring; (c) designing a backbone ring topology that includes at least the ring hubs and the destination node; (d) designing an access ring topology for each of the demand node groups so that the backbone ring and access ring topologies constitute a preliminary network topology; (e) evaluating a cost associated with the preliminary network topology; (f) selecting at least one alternative ring hub to provide a new set of ring hubs; (g) repeating steps (c)-(e) for the new set of ring hubs to determine if a resulting network cost estimate is reduced; (h) repeating steps (f)-(g) until a minimum cost network topology is produced. Other aspects of the invention are directed to hub and spoke topology design and SONET transport design.