Adaptive resource reservation protocol for high-speed resource information advertisement

This paper proposes an adaptive resource reservation protocol for high-speed resource information advertisement. The adaptive resource reservation protocol (ARRP) is a protocol that adaptively decides whether to uses a 1-way reservation scheme or 2-way reservation scheme on the basis of resource information in the route calculation. Examples of the resource information are unreserved bandwidth and unreserved wavelength. The 1-way reservation is used when all links along the calculated route has enough resources. Otherwise, the 2-way reservation is used. GMPLS (Generalized Multi-Protocol Label Switching) network, the source router decides a label switched path (LSP) route using collected resource information from the network. The resource information is advertised by an OSPF- TE (Open Shortest Path First-Traffic Engineering) protocol. If the unreserved resource information of calculated LSP route is too old and inconsistent with the current information, the resources on the LSP route cannot be reserved and thus data loss will be occurred. In order to support real-time unreserved information update, quite a lot of update packet transmissions are needed. It causes increasing of the processing load of all routers. Therefore OSPF-TE cannot advertise real-time unreserved resource information. In the proposed method, when a LSP route is established or released by ARRP, only one packet informs update information of each links along LSP route to all edge routers. The proposed method can support more frequent updates by decreasing the amount of the update packets and can advertise the real-time resource information. By use of the real-time resource information, the proposed method certainly guarantees the reservation of resources on LSP route in spite of the 1-way reservation. By the computation simulation, it is indicated that the number of the control packets in proposed method is one digit less than that in the conventional OSPF-TE. Compared to the OSPF-TE, the proposed me- - thod keeps low blocking probability even when traffic occurs more frequently. Thus, it is shown that the proposed method effectively use network resources.