The stable multicast flow aggregation (MFA) problem in internet protocol (IP) over optical network under the dynamical scenario is studied.Given an optical network topology,there is a set of head ends and access routers attached to the optical network,in which each head end can provide a set of programs (IP multicasting flows) and each access router requests a set of programs,we find a set of stable light-trees to accommodate the optimally aggregated multicast IP flows if the requests of access routers changed dynamically.We introduce a program correlation matrix to describe the preference of end users' requests. As the original MFA problem is NP-complete,a heuristic approach,named most correlated program first (MCPF),is presented and compared with the extended least tree first (ELTF) algorithm which is topology- aware.Simulation results show that MCPF can achieve better performance than ELTF in terms of stability with negligible increment of network resource usage.
In this paper,the sharing schemes of multicast in survivable Wavelength-Division Multi-plexed(WDM) networks are studied and the concept of Shared Risk Link Group(SRLG) is considered.While the network resources are shared by the backup paths,the sharing way is possible to make the backup paths selfish.This selfishness leads the redundant hops of the backup route and a large number of primary lightpaths to share one backup link.The sharing schemes,especially,the self-sharing and cross-sharing,are investigated to avoid the selfishness when computing the backup light-tree.In order to decrease the selfishness of the backup paths,it is important to make the sharing links fair to be used.There is a trade-off between the self-sharing and cross-sharing,which is adjusted through simulation to adapt the sharing degree of each sharing scheme and save the network resources.
