Nt1310 Unit 3 Assignment 1

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Network coding can play its role in layered multicast by maximizing the aggregate throughput of all the receiving nodes in the network. This can be explained with the help of an example as shown in Fig. 5. Consider a network of six nodes where a source node s tries to send a data stream to two sink nodes t1 and t2. The data stream consists of five layers L1, L2, L3, L4, and L5, each with a transmission rate equal to one. The capacity of each link in the network is also shown in Fig. 5(a). From the capacity of each link, we can see that the achievable aggregate throughput from s-t1 and s-t2 is 5 and 2, respectively. Fig. 5(b) shows a layered multicast without using network coding, where the links are divided into different layers using simple routing. …show more content…
However, the achievable throughput can be increased by performing network coding either within each layer, referred to as intra-layer network coding, or across different layers, referred to as inter-layer network coding. Figs. 5(c)-(e) show intra-layer network coding being applied to our example, where the network given in Fig. 5(a) is split into subgraphs and each subgraph transmits a layer of the data stream with capacity equal to one. In this way, network coding allows both the sink nodes t1 and t2 to achieve the total aggregate throughput of seven. Fig. 5(f) shows inter-layer network coding being applied to our example. In this method, the intermediate node 3 linearly encodes layers L1, L2, L4, and L5 into L1+L4, and L2+L5 to achieve a maximum throughput of