Hierarchically distributed PCS for GMPLS multilayered networks

Recently, requirements for integration of various networks, such as optical fiber networks and IP networks, are becoming stricter. To achieve this integration, generalized multiprotocol label switching (GMPLS) is now receiving more attention. The main feature of a GMPLS network is its multilayered complexity, which sometimes places a large burden on source GMPLS routers to determine the optimal routes to destinations and causes label switching path (LSP)-setup delays. To reduce this source-router burden, we propose a hierarchically distributed path computation server (HDPCS) that reduces the setup delay and conducts flexible routing depending on each GMPLS domain´s or each GMPLS layer´s routing policy. Because each HDPCS is allocated to each domain, including interdomains, which have several domains under them, each domain´s security is also assured depending on each domain´s security policy. Forwarding adjacency (FA) is introduced as one of the countermeasures against GMPLS multilayered routing problems and the OSPF routing protocol is applied to determine the end-to-end routes. Therefore, we compare the performance of the HDPCS with OSPF-based routing and demonstrate its applicability