Research On Topology Discovery Method And Implementation Of Network Management System In IPv6

With the rapid evolution of network technique, network management is gradually becoming as one of the important factors for network design and maintenance. Especially, the next generation network with the core of IPv6 protocol is deployed gradually, which makes the network management in IPv4/IPv6-mixed environment particularly significant.Correct network topology is the basis for network management. It can support network performance analysis, fault alarm and network data configuration. The measurement and analysis of the metrics of the network performance, network fault and network configuration requires a known network topology. IPv6 has been recognized as the next generation Internet protocol. And ISPs are gradually provided the services of IPv6. Thus, the importance of topology discovery in IPv6 is more and more apparent.This paper proposes a centralized topology discovery method with smallest-redundancy in IPv6 environment. Nowadays, the topology discovery method based on ICMP can be divided into distributed method and centralized method, both of which produce the probing redundancy inevitably for probing actively. The distributed topology discovery is difficult to deploy, and its cost is very high. It also has a lot of limitations in redundancy reduction, due to inter-redundancy. Thus, it can't discover topology in a network-friendly manner. The centralized topology discovery is easier, and it only produces the intra-redundancy due to the single monitor. This paper analyses the trace data of Scamper monitors offered by CAIDA, and measures the intra-redundancy generated by one monitor probing. The results show that the majority of intra-redundancy is generated nearby the probing monitor. To this point, this paper introduces the idea of Backward algorithm to reduce intra-redundancy in IPv6, and presents Midway algorithm in practical network environment. The experiment results show that this algorithm can reduce redundancy of nodes near monitor by two orders of magnitude, and only about 2% of interfaces are missed. Since routers in IPv6 have to support the source routing function, centralized topology discovery method can detect the cross link. This paper shows the centralized method in IPv6 is feasible, and introduces cross-link discovery algorithm to guarantee the coverage. Combining smallest-redundancy algorithm, this paper presents a centralized topology discovery method with smallest-redundancy. It makes use of the new feature of IPv6, and discovers topology in a network- friend manner.This paper designs an IPv4/IPv6 compatible SNMP communication mechanism, proposes a topology discovery algorithm based on SNMP in IPv4, and analyses the limitation factors for topology discovery based on SNMP in IPv6. On this basis, we design and implement a network management system in IPv4/IPv6. The system mainly consists of three function modules: topology management module, network performance management module and fault management module, respectively. This system has been applied in practical network environment successfully.