A mixed integer formulation for multicast flow assignment in multilayer networks

Multicast has been being developed as a very promising technique to data delivery to a group of destinations simultaneously. Except of first implementation for multicasting in the Internet aka IP Multicast, for past few years some systems defined for end-hosts overlay network have been successfully designed and implemented. Additionally, overlay multicast defined for end-host based networks has been gaining an advantage over IP Multicast during recent years. It derives from the fact that the overlay architecture for multicast streaming provides potential scalability and easy deployment of new protocols independent of the network layer solutions at relatively low costs. Thus overlay multicast and network-aware multicast have been developed concurrently. On the one hand, IP Multicast provide pure network aware multicasting and the lowest packet redundancy on physical links, on the other hand, overlay multicasting creates logical multicast topology which is realized using unicast flows on network level. In this paper we combine advantages of both end-host systems and network awareness and formulate a mixed integer program for optimization of multicast tree topology and its network level unicast realization. The proposed formulation can be applied for deriving either lower bound of flows costs in existing systems or for designing new cooperative multilayer protocols for effective multicast transmission.