The Application Research Of PMTU Protocol In IPv6Network

In order to enhance the forwarding efficiency of the network equipment,forwarding equipments are not allowed to fragment the datagrams in the transmission ofIPv6. The size of the datagrams can only be decided by the source. It is to say that onlythe source has the ability of fragmenting datagrams. The source must carry out PMTUdiscovery that it can decide the size of the forwarding datagrams. So the protocol ofPMTU discovery is very important and must be achieved in IPv6. The fast developmentand wide application of IPv6make that PMTU discovery protocol must be supportedand achieved by many network equipment manufacturers.This paper analyzes the theoretical basis of the PMTU technology and gives thecorresponding solutions to the problems you might encounter in the actualimplementation process. This paper also introduces the mainstream PMTU detectionalgorithm, including the incremental detection algorithm, the decreasing detectionalgorithm, layered detection algorithm and detection algorithm based on the experienceof K-segment hierarchical. But PMTU detection is in the use of hop-by-hop manner. Insome cases, the detection rate is quite slow and modifying the value of the PMTU entryfrequently will bring additional costs to the system. So this paper proposes an improveddetection algorithm.This paper carries out a detailed needs analysis and describes the specific functionsthat the PMTU module should implement. The fucntions of the PMTU module aredivided into16specific needs points in tatal. And each specific needs point has adetailed instruction. Besides, this paper carries out a detailed design to the developmentprogram of PMTU module, including the distribution of data and control flow, entrystructure, entry management, aging mechanisms, smoothing entry and database design,user interfaces and so on. It also determines the specific functions and the functioninterfaces that should implement of each sub-module.This paper carries out a concrete realization to the PMTU design. It discibes themain data structures used in the process of PMTU module in detail. And detailedinstructions are discribed on the interface functions of each PMTU submodule,especially the interface functions provided to the external application modules byPMTU module. Finally, the paper tests the conrete functions of PMTU module andsystem test results are analyzed. So that the problems occuring in the development process of PMTU module have been resolved. The quality of the entire project can beguaranteed, too.