Centralized Routing vs. Distributed Routing

Difference Between Centralized Routing and Distributed Routing

Routing is the process of choosing the paths to be used to send traffic network and sending packets along the selected sub-network. Centralized routing model is the one wherein routing is done at the center using a centralized database. In contrast, distributed routing model is a model of routing, which deals with the process of routing using a distributed database.

What is Centralized Routing?

Centralized routing model is a model of routing in which routing is done at the center using a centralized database. In other words, the routing table is kept to a single “central” node, which should be consulted when other nodes makes a routing decision. This central database has a global network view. Centralized routing is considered to be the most correct in the specific areas with systems providing DWDM (Dense Wavelength Division Multiplexing) transmission. This is because these DWDM systems contain OADM (the Optical Add-drop Multiplexer) that can be reconfigured in the beginning and the end point of the medium of communication. Proponents of centralized routing suggest that because most information such as details of SRLG (Shared Risk Link Group) and performance parameters do not change often (and these information can never be discovered or self reported), they are ideal to be accumulated in a central database. In a centralized model, status information can easily be accessed. Thus, the dependency information (regarding routing) between the circuits (to ensure diversity exists) can be manipulated relatively easily when the terminal is not shared between the circuit and is ideal for a model of centralized routing. The centralized model uses global information public. Calculations that are done (like the pre-computer to restore trails) can be highly benefited from the global information and thus is suitable for a centralized model.

What is Distributed Routing?

In the model of distributed routing, each node maintains a separate routing table. Distributed routing model is a model of routing, which is great for domains that can be identified as completely opaque. The main reason for this is that the constraints on impairments do not play a role in routing in the domains mentioned above. In case of failure (when there is a need to restore quickly), distributed routing system can be counted on to incur the responsibility of the on demand computation of recovery paths for each failed light-paths (even at the point of detecting an expected failure). Finally, the distributed routing model is highly consistent with existing Internet own distributed routing philosophy.

What is the difference between Centralized Routing and Distributed Routing?

Centralized routing model performs routing using a centralized database, while distributed routing business deals to achieve routing using a distributed database. In simple terms, a central node keeps the routing table in the centralized model, while each node keeps a routing table in the distributed model. Because much of the information does not change often, many believe that this information is very suitable to be accumulated in a centralized database. The pre-calculations necessary for the restoration can take advantage of global information available in a centralized database. But, unlike distributed routing system, we can not count the centralized system to incur the responsibility to request the on-demand computation of recovery paths for each of the light paths that have failed (at a time of finding out an expected failure). Unlike the centralized approach, the distributed routing model is highly consistent with existing Internet’s own distributed routing philosophy.

 

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