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Showing posts from February, 2014

Effects of Buffer Size on Delay Tolerant Routing

In this post, we look at how buffer size affects, if at all, the performance of the routing protocols in DTNs. For this purpose, we will consider the following five routing protocols:
EpidemicPROPHETSpray-and-Wait (SnW) First Contact (FC) Direct Delivery (DD)  Detailed discussion of these protocols is scoped out here. We just note that in case of Epidemic, there is unlimited replication of the messages. In PROPHET, however, the replication is usually less than that of Epidemic. On the other hand, SnW has a fixed limit (L) on possible number of replications of a message. Finally, FC and DD involve message forwarding -- not replication. So, in the latter cases, there is always a single copy of any message in the DTN.

We will consider the buffer sizes from 20 MB to 180 MB, both inclusive, in steps of 20 MB so that we have total 9 different buffer sizes. We will use the real-life connection traces from Infocom'06. Therefore, we will need to simulate 5 * 9 = 45 scenarios to get the rel…

Discover Plotting Utility Within Ns2web

In my previous articles, I have discussed about the Virtual Labs and IEEE WCM Feature Article on ns2web. Today, I would briefly discuss about ns2web with specific focus on one of its more general features -- data plotting utility.

Ns2web is the core component of the Advanced Network Technology Virtual Labs. At a high level it has two basic jobs to perform:
Execute the NS-2 simulations in a remote server based on the user input code. Help users perform different types of post-simulation analysis using the trace file generated. As such, ns2web itself becomes a sort of mini-project :) Currently, ns2web and the version of it used with the ANT VLab differ on a few minor aspects. The former offers a ``guided scenario generator'' to the users, and an option to export the graphs as external images.

However, ns2web is not only for performing network simulations! The software provides a useful feature that might interest you if you want to quickly plot some nice line plots.

As shown …