Application Layer Multicasting

Application Layer Multicasting

Introduction

Multicasting can be defined as the transmission of information and data to more than one user. Over the internet the function of the network layer is to implement the functionality of data forwarding among users of different networks such as the local area network. A more innovative approach was given to the IP multicast to add the multicast to the internet protocol layer. The IP multicast architecture provides the network of routers as a data tree. As the data flows through the tree it is also being replicated at different branch points through the routers. The multicasting technique is a very effective and efficient way to perform distributions of group data. This is because it allows decreasing the replication of packets of information in (WAN) to as low as possible. However, after the initial start of IP multicasting it was being limited due to many technical and non technical complications. One of the reason was the IP multicast needs routers in order to maintain each group state. The table of forwarding and routing needs to be maintained for entry of every unique multicast group address. This is different from the unicast techniques as the multicast is not easily totaled. This increases the complexity in the table and the routers. Furthermore, there is also a load of mechanisms such as reliability and traffic control of the IP multicast. Thus, we see varying multicasts in the network layer of internet service providers.

Discussion

There is a great increase in the P2P applications which rely heavily on the data transmission. The P2P applications greatly rely on multicast communications in which peers are able to join a multicast group. Due to this the reliability, efficiency and the scalability of such applications are being firmly coupled with the multicast techniques. Over the network layer, the IP multicast provides great efficiency reliability and scalability. Furthermore, in the implementation of IP multicast the routers are to be properly configured. This is hard to be implemented in a large scale basis or open network. Due to this research had been made in order to provide environments where multicast communication could be implemented on a wider range. This is where the Application Layer multicasting is being implemented.

The application layer multicasting is different from the network layer multicast. This is because in the network layer multicast the data packets are being copied at the routers within a network. In the application layer multicasts theses packets are being copied at the end hosts. The replication of packets at end hosts provide a creation of overlay networks which give a more efficient overlay for the transmission of data. Some important aspects of the application layer multicast are as follows

Data quality

The data path and its quality are observed through the stress and stretch. The stress metric is the router of the topology and has the job to count the amount of known packets that are being sent by the protocol layer over that particular link. In case of a network layer ...