Research On Some Key Issues Of ISIS MTR

As a kind of link-state interior gateway routing protocol,Intermediate System toIntermediate System(ISIS) is widely used in the major telecom operators in Europe withthe advantage of fast convergence rate and being easy to extend. The technology ofMultiple-topology Routing(MTR) is an intelligent routing scheme put forward in recentyears.It makes different business having different requirements for link quality hasspecial network topology by dividing a physical topology into multiple logical topologywithout changing the original physical topology,thus preventing large netwok trafficaffecting some business.ISIS MTR provides a new perspective for load balancing,trafficengineering and network security.But storage of all kinds of network resources results inthe larger memory consumption and the slower convergence speed of routing with thegeneration of a large number of logical topology.The dissertation has a study on the key technology in the implementation of ISISMTR in RFC5120,and optimizes it based on a thorough knowledge of ISIS routingprotocols.ISIS MTR consists of three modules including neighbors buildingmodule,link-state information maintenance module and routing calculation module. Thelink-state information maintenance module and routing calculation module areoptimized in the dissertation.To solve the problem of large memory occupied in theoriginal storage solution with child topology and standard topology storing link-stateinformation alone while existing a large number of logical topology, the dissertationproposes a new solution of child topology link-state information storage.In the solutionchild topology and standard topology information are stored in a doubled linked list,thetopology ID stored in sequence in the first layer and information about each topologystored in the second layer.And the link state information is only stored onetime,effectively improving the efficiency of memory storage.To solve the problem oflow path computing efficiency in the original algorithm of ISPF under the condition oflarger computing scale and more complex network environment, the dissertationproposes an improved algorithm of ISPF by optimizing the incremental calculationprocess, effectively accelerating the routing convergence speed.To solve the problem oflarge memory occupied in the original storage solution with every topology storingrouting information alone while existing a large number of logical topology, thedissertation proposes an improved solution of routing information storage combinedwith the characteristics of the network topology.Based on the new routing informationmaintenance solution, the dissertation optimizes routing calculation scheme, effectively reducing the memory load of router and raising the efficiency of resource utilization andnetwork operation.In the following research,the application of MTR in load balancing and networksecurity should be focused on.By designing topology and the security policyreasonablely,the physical link achieves the optimal network load and the safety of theservice is guaranteed.