QoS aware multicast routing and meta- heuristics over multi-layered satellite-hap networks

Abstract

In the last few years, multimedia broadband services and applications are growth. More resources have been requested to the networks and more Quality have to be supplied for the services. Moreover, new kind of networks were born such as wireless network and cellular networks such as 3G/4G and UMTS, also wired connections are evolved and more resources are available to allow new services and applications. In these years, social networks and multimedia applications are increase exponentially making possible new field of applications. With new technologies, in fact, it is possible to supply utility services such as tele-health, wireless health monitoring, public safety services and much more services over the internet, WAN and so on. Moreover, dedicated services and networks can be rapidly installed in case of emergency scenarios such as war or natural disaster cases. For these reasons, new network architectures can be implemented to offer a wide range of services. In particular, it is thinkable to interoperate between different network such as Satellite network, Cellular network and Wired Network to take advantages from all networks reducing weakness. Moreover, it is necessary to increase resources availability making efficient choices and optimizing reservation along links on which network data flows. To make these scenarios possible services and network have to offer a reasonable Quality in terms of Quality of Service (QoS). To do this new protocols and algorithms capable to take advantages from modern network infrastructures have to be designed. A wide range of services can be distributed on the network in a multicast manner, for example multimedia data such as video and audio can take advantages from multicast transmission reducing in a drastic manner the number of control packets and data packets sent into the network. In case of unicast transmission, in fact, a higher number of packets than the multicast are sent into the network to allow each destinations to receive data flows. In order to make more robust, reliable and scalable multicasting on the hybrid network, a multicast algorithm has been associated to the the mul ticast protocol, when a multi-constraints QoS aware multicast have to be addressed. A multicast algorithm that has the main goal to find a multicast tree in an multi-constraints environment belongs to the NP-Complete class of problem. In literature this is known as a Steiner Tree Problem (STP). In order to solve this issue a new class of algorithms has to be addressed. In particular, taking into account limited resources of the routers and time limits a heuristic method has to be designed. In these last years a series of algorithms that derive by the observation of natural evolution and biological process that are also called biologic algorithms, pay out much attention. In this works, the Genetic Algorithm (GA) adapted to Multicast issues has been designed and proposed to provide a better resource management that allow a higher number of multicast sessions and higher number of users to join into the network. This allows a network cost reduction and offers better services with a higher quality to the community. To spread services around wide areas with same quality, a broadband network, which are not sensible to terrestrial overloaded network, have to be addressed to distribute with reliability and scalability multicast services. Satellite network equipped with newest architecture such as DVB-RCS or DVB-S2 that implements two way services represents an optimal solution to distribute broadband services, because it also support a certain realtime interaction between sources and destinations without changing of network. This architecture has the main problem to have a higher round trip delay owing to the distance between satellite and Earth surface, in fact, some applications such as realtime applications do not support satellite communications. For these reasons, and in general to reduce, where possible, round trip delay an intermediate network has been introduced into infrastructure. HAPs meshes are composed of several on air platform that provide wireless broadband communications. They can interact with cellular platforms or with most common wireless networks changing their payload if necessary. An interaction of Satellite and HAP can reduce delays and increase network performances. In order to make this possible an efficient multicast protocol capable to address in an efficient manner data flow and protocols interaction between several entities has been designed and proposed. Moreover, using aforementioned algorithm, efficient routing has been addressed. In this hybrid network, which is based on a DVB-RCS like architecture, local communication can be made exploiting HAPs or wired network. instead, in case of far connections satellite link can be used as bridge among HAPs network, otherwise satellite can be used directly to connect a terrestrial router with another one when HAPs links are overloaded or in case of some areas where HAP coverage is not present.