With the rapid extension of broadband communication service, it is very difficult to estimate the increase and fluctuation of the traffic in network accurately and, research and development of the traffic engineering which utilizes the network resource effectively is advanced. Traffic engineering (TE: Traffic Engineering) It is of processing which selects the pass for data traffic in order to optimizes the usage condition and traffic performance of the network resource simultaneously, and o promote the reliable network operation. With the traffic engineering, there is the traffic oriented which designates minimization of packet loss and communication delay and the largest conversion of throughput as purpose and the resource oriented which designates the optimization of coefficient of use of the network resource as purpose. Common performance target to two is to suppress congestion in the network to the minimum. If congestion can be suppressed to minimum, the packet loss and the communication delay decrease, and the improvement of throughput can be achieved. As a result, communication quality at user level means to improve rapidly. In order to actualize the traffic engineering, it is necessary to allocate of the resource which considers the state of the network. The case where the traffic engineering is executed, supervision of the resource, analysis of traffic quality, model of traffic and control of traffic become necessary. The high-level traffic engineering it becomes actualization possible by the fact that 4 items above are done accurately.
Traffic Engineering with GMPLS
GMPLS (Generalized Multi-Protocol Label Switching) forwards traffic by using the label. It is called the rooter which it has adjoined with GMPLS domain and other domain the edge rooter, communicates between the edge rooter. As the feature of GMPLS, there are collection of resource information of network and the explicit route which is by the source routing. Method of resource data gathering is spread resource information of each rooter with OSPF-TE which expands OSPF.Using the resource information which collected, the source edge rooter does the route calculation to the destination edge rooter. When the communication by the IP packet is used, the actualization of TE was difficult because the following hop estimate difficulty. But, with GMPLS because it can decide route with the source edge rooter, it becomes explicit route. When being route decision, it becomes possible to correspond to the change of the resource of network. Depending, the traffic engineering which uses GMPLS is observed.
Fast Unreserved Resource Information Advertising Method
With GMPLS resource information is spread by OSPF-TE. Even in resource information it tries observing in unreserved resource information. Unreserved resource information changes frequently with the occurrence of call and it is the important element which is used for route decision in TE. When reservation possible resource information accurately and in high speed it is spread in the edge rooter, it becomes possible to do TE whose precision is high. With former OSPF-TE it becomes necessary to transmit many update packets because it corresponds to frequent change, and it becomes difficult to process in the rooter and it becomes impossible to spread accurate information. By the proposed method, edge router transmits lumping together the unreserved resource information of route at the time of the route establishment and release of RSVP-TE. It becomes possible to inform about modification of the unreserved resource the edge router in high speed, and it becomes possible also for load of the rooter to make decrease by the fact that it decreases the update packet.