基于流量敏感度的IBGP拓扑设计问题建模与分析

Designing IBGP Networks Based on Traffic Sensitivity: Models and Analysis

研究IBGP路由反射网络的健壮性问题.分析了IGP路由恢复时间对IBGP会话的影响,提出一种新的基于IGP路由恢复时间概率分布的IBGP会话故障概率计算方法.分析了已有的各种IBGP网络设计测度,提出一种新的测度:流量敏感度.基于该测度定义了路由反射器可冗余及会话约束的IBGP拓扑设计问题,讨论了路由反射器冗余度和流量敏感度的关系,给出该问题的优化下界.对每一个簇内都有一个冗余路由反射器的拓扑设计问题给出可解条件,证明其是一个NP难问题.

This paper focuses on the design of robust IBGP route reflection networks, which are very important to the reliability and stability of Internet. A new approach is proposed to calculate the failure probability of IBGP sessions based on the probability distribution of IGP routing recovery time. To measure the robustness of IBGP, a new metric： TS （traffic sensitivity） is presented. Based on this metric, the optimization problem of finding the most robust IBGP route reflection topologies is investigated, in which a cluster is allowed to have one or more redundant route reflectors and the maximum number of IBGP sessions a router can have is limited. The relationship between the route reflectors redundancy and the robustness is discussed, and the lower bound of this problem optimization is given. And for a special case that there is a redundant route reflector within each cluster, the solvability conditions for the problem are given and it is shown that the problem in general is NP-hard.