Video streaming over the internet using application layer multicast
Creators: name: Rong, Bin
Publisher: name: RMIT University
Year: 2024

description: Multicast is a very important communication paradigm. However, the deployment of multicast at IP layer is very slow, due to development and deployment issues such as ISPs' lack of incentives to update routers and inter-operability among multicast routing protocols.<br><br>Application Layer Multicast (ALM) is a good alternative, where participating peers organize themselves into a logical overlay network atop the physical links and data is \tunneled' to each other via unicast links. The distinctive feature between IP multicast and ALM is that in ALM, data replication and forwarding functionalities are performed by participating peers (a.k.a. end systems), rather than the routers in Internet Protocol (IP) multicast. This fundamental difference enables ALM to be able to circumvent the development and deployment issues of IP multicast, by exploiting the resources (e.g., CPU cycles, storage, and access bandwidth) at the edge of the network. Nevertheless, it also raises other challenges, as peers are not as stable as routers since they may join and depart the on-going session at will. In this thesis, we address some of the challenges and they are summarized as follows:<br><br>First, most current P2P or ALM streaming systems are equipped with a non-scalable membership management algorithm, greatly hindering their applicability to large-scale implementations over the Internet: they either rely on a central entity to handle group membership, or simply assume that all group members are visible to each other and flooding is the main mechanism used to disseminate membership-related updates to all participating group members. This implies that they are only applicable to small groups.<br><br>Second, one of ALM's prominent features, flexility, has not been fully exploited: moving the multicast functionalities from lower layer (IP layer) to higher layer (Application layer) can greatly facilitate the integration of Quality-of-Service (QoS) support. The end-to-end philosophy states that it is better to leave those functionalities to higher layers because the heterogeneity among users' requirements can be handled much better by end users, rather than the network. However, QoS, and in particular, reliability has not been thoroughly addressed in existing ALM schemes.<br><br>Third, admission control algorithms are essential to the success of any ALM<br>system, due to the fact that in ALM, each peer acts as both a client as well as a server. On the other hand, the heterogeneity among peers, in terms of their computational power, storage capacity, and access bandwidth, further complicates the design of a good admission control. Several contributions are made to address the aforementioned research challenges, and they are outlined as follows:<br><br>The first contribution is a devised gossip-based membership management algorithm that is able to collect and disseminate membership-related information under high rate of churn, using relatively low communication overheads.<br><br>The second contribution is a reliability-centric multicast tree construction algorithm that greatly enhance peers' perceived reliability.<br>The third contribution is a QoS-aware tree construction algorithm that accommodates the heterogeneity among peers, such as access bandwidth, network distance, and reliability.<br>The last contribution is the identification of the admission control problem in this overlay video streaming.