Method for adapting link weights in ralation to optimized traffic distribution

Abstract

The invention relates to a method which is used to adapt link weights or, link costs, for optimized traffic distribution within a communication network. According to said method, a loop is circulated until an interruption criterion is met. The individual iterations comprise the following steps: Routing of traffic within the communication network is calculated based on link cost paths. Parameter values used for optimization e.g. the link-related volume of traffic, are determined for the individual links by means of the calculated path, and an expected volume of traffic and the link are determined for the parameter having the highest value. When the highest determined value is equal to or less than the valve of the previous step (interruption criterion), the link costs are increased for the determined link. Said method enables link costs and paths for optimized traffic distribution to be determined in an economical manner.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is the US National Stage of International Application No. PCT / EP2005 / 050149, filed Jan. 14, 2005 and claims the benefits thereof. The International Application claims the benefits of German application No. 10 2004 004 793.6 filed Jan. 30, 2004, both applications are incorporated by reference herein in their entirety.FIELD OF THE INVENTION [0002] The invention relates to a method for adapting link weights in a communication network formed from links for an optimized distribution of traffic within the communication network as regards the volume of traffic expected for the communication network and in relation to a parameter relating to link usage. SUMMARY OF THE INVENTION [0003] The invention lies within the area of communication technology and in particular deals with the transmission of data over packet-oriented networks. [0004] The optimization of data transmission over packet-oriented networks, especially over IP (Int...

AI Technical Summary

Benefits of technology

[0005] The best possible distribution of the traffic routed over a communication network is important, on the one hand in relation to avoiding overload situations, on the other hand good traffic distribution is the requirement for a good utilization of the existing resources and especially the bandwidth available. The traffic distribution within a communication network depends on the routing within the network or the paths on which the traffic is routed through the network. By far the most widespread routing method for packet-oriented networks based on an IP protocol is what is known as the OSPF (Open Shortest Path First) method or protocol. In this method, for traffic to be routed between two nodes, the shortest path in the sense of a metric between the two nodes is defined. The path is normally determined with the aid of what are known as link costs. The terms link weight or link weights which are normally employed by specialists as synonymous with link costs are also referred to below. The link costs or link weights are values administratively assigned to the links, said values representing a measure of how well the relevant link is being used. In the simplest case the link costs are equal to 1 for each link, i.e. all links are treated in the same way. For routing which minimizes the link costs this method automatically determines the shortest path between two nodes as regards the number of links or the number of hops. Changing the link costs allows the determination of the routes and thus the distribution of the traffic within a communication network to be influenced. Controlling the traffic distribution by adapting the link costs is generally possible with routing methods which operate using a metric and the allocation of link costs, e.g. in the IS-IS (Intermediate System-Intermediate System) protocol or for example the ECMP (Equal Cost Multiple) method, which was defined within the framework of the OSPF protocol and makes provision for the use of a number of paths determined by means of OSPF for routing between two nodes.

[0011] An improved or optimized traffic distribution is obtained through the invention by increasing the link costs of heavily loaded links. In comparison to conventional methods the inventive method is simpler and can be implemented without any problems. For determining paths within the framework of the ECMP (Equal Cost Multiple) method it is useful to operate in the method with whole-number link costs or whole-number increases in the link costs, since in this way it is more likely that alternative paths with the same accumulated costs for the connection of two nodes are produced, so that, as provided for in the ECMP method, traffic can be distributed to the various equivalent paths. As a start point it is useful to initialize all link costs with the same value, for example with 1.

Problems solved by technology

Conventional methods for optimizing traffic distribution by adapting the link costs are comparatively complicated.

Because of the complexity of this method the link costs are currently frequently not optimized.

Unavoidable adaptations of the link costs are frequently performed manually, which entails a high risk of errors.

Thus the traffic optimization in real networks is likely to be less than optimal.

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