Inter-Layer PCE Based Scalable Packet Forwarding with ID/Loc Separation

The explosively increasing number of Internet subnetworks and related network prefixes is creating a severe scalability problem in the FIB (forwarding information base) table size of Internet core transit routers. IRTF has been studying various solutions to mitigate this Internet scalability problem, and ID (identifier) Loc (locator) separation has been proposed as a reasonable solution. The packet forwarding with ID/Loc separation, however, is requiring i) an efficient mechanism of IDLoc mapping distribution, and ii) managements of inter-domain traffic engineering (TE) tunnels among ITRs (ingress tunnel routers) and ETRs (egress tunnel routers). In this paper, we propose an efficient ID-Loc mapping distribution system and the management of inter-domain TEtunnels among ITRs and ETRs based on the PCE (path computation element) architecture. The proposed inter-layer inter-domain PCE-based ID-Loc mapping distribution system provides partial push mechanism for ID-Loc registrations and updates from the ETR, and selective pull mechanism for ID-Loc mapping queries from the ITR. The PCE-based TE-tunnel management system provides inter-domain path computations for TE-tunnels, and inter-layer path computations for optimized packet forwarding with scalability. From the experimental implementation of the proposed PCEbased TE-tunnel management, we found that the FIB table size of the tier-1 core transit routers can be reduced to 35 ~ 40% by just 15 ~ 20% of TE-tunnel establishments in tier-2 domain networks. Also, the PCE-based ID-Loc mapping distribution system can support inter-domain path computation for scalable packet forwarding within 50ms of initial packet delay. The performances of the proposed PCE-based TE-tunnel management for interdomain path computations and TE-tunnel establishments are analyzed.