Research And Implementation Of Neighbor Discovery Protocol In Distributed Router

With the popular use and the rapid development of the Internet, the application ofIPv4has exhibited many drawbacks, including address resources shortage, low qualityof service, lack of mobility, weaknesses of auto-configuration capability and poorsecurity. The transition from IPv4to the next generation of Internet Protocol(IPv6) isan inevitable trend of the Internet’s further development. The neighbor discoveryprotocol is the fundamental protocol in the IPv6protocol cluster. It provides routerdiscovery, stateless address auto-configuration, duplicate address detection, link-layeraddress resolution, neighbor unreachability detection, and other functions for networkdevices. Distributed router using distributed processing architecture, has a good loadbalancing effect. Therefore, implementing the neighbor discovery protocol ondistributed router could improve the efficiency of data forwarding, and this work hasimportant research significance and practical value.This thesis analyzes the principle and mechanism of the neighbor discoveryprotocol according to the neighbor discovery protocol standards. And then I design andimplement neighbor discovery protocol in distributed router. My main contributionsare as follows:①According to the principle and mechanism of the neighbor discovery protocol,I analyze and research the relationship of neighbor discovery module with peripheralmodules, including interface management module, address management module,forwarding information base module, packet forwarding module and command-linemodule, etc. And then we determine the role of the neighbor discovery module in thepacket forwarding system.②Based on the role of the neighbor discovery module in the packet forwardingsystem, we design data structure of neighbor table entry and linked list, determine thekey in querying neighbor table entry, depth of table entry hash bucket and rule of tableentry learning, and divide functional sub-modules.③I design and research the table entry synchronization mechanism between themain control board and interface board in distributed forwarding, establishment ofreal-time unicast channels and bulk multicast channel between the main control boardand interface board.④Distributed routers require real-time synchronization on the entries of neighbor table, however, the synchronization and study on the entries have timing relationshipand it could lead to taking much time for caching when router forwards the first packet.In order to solve this problem, I propose the method of adding temporary entries.In a word, this thesis analyzes several problems involved when I implement theneighbor discovery protocol on distributed router. These problems includecommunication between boards, main-backup switch, long caching time of first packet.And then I propose the corresponding solutions. Finally, the high performance ofneighbor discovery protocol is evaluated through network testing, capturing packets,and debug information analysis.