Design And Implementation Of OSPFv3 Protocol In The High-Performance IPv6 Router

This dissertation is devoted to the researches of the design and implementation of OSPFv3 protocol in the high-performance IPv6 router according to the requirements of the tenth five-year plan 863 IPv6 router project. Based on the thorough analysis of OSPFv3 protocol, we propose a modularization and a multi-thread mechanism implementation method. We lay some emphasis on the receiving and sending packet and the design of the link state database. Through the analysis of the routing table computation, we adopt a modified WARR algorithm to reduce the routing table computation cost. The main work of this paper is as follows:Firstly, aiming at the complex interface model and the outstanding parallelism, we adopt the modularization measure, give the dividing measure and design the interfaces. We make use of the implementation method of multi-thread mechanism in GNU Zebra, all threads are executed through event scheduling. The event can be a kind of current interface form, thus the interior and the outer interfaces can be unified and simplified;Secondly, we design a layered method to deal with the 5 types of protocol packet. This layered method simplifies the operation during protocol packet implementation; we bring forward a method to receive and send the protocol packets in buffer with high efficiency. With the iovec structure, we fill in the packet or receive packet to make the receiving and sending function current. At last, we design the mechanism to receive and send packet.Thirdly, based on the characteristic of LSAs, we not only design a series of layered data structure to deal with LSAs, but also design a managing structure to do with these LSAs. Through this managing structure, the protocol can handle all LSAs without regard to the type of LSAs; the storage manner of LSDB is vital to implement protocol, because it joins the protocol implementation and routing table calculation. In this paper, we adopt the Radix tree structure to store LSAs into LSDB, because the time complexity of Radix tree is O(logn).Fourthly, we adopt an intra-area routing table calculation algorithm-WARR and modify its detecting and maintenance algorithm. Thus, we can divide an OSPFv3 area into multiple disjoint regions, then every routing node (RN) calculates routing table independently. After calculating, the RN broadcasts its updating routing table to other RNs. By receiving the updating information, the other RNs will update theirs own routing table. In theory, this modified algorithm is able to speed up the intra-area routing table calculation observably.