Manju,

As far as I can remember, there is a module available for supporting DTNs in NS-2. However, I have never used that.

Personally, I would recommend using the ONE simulator when you are concerned with  opportunistic communication as in this case. The ONE simulator has a modular structure, which makes development real easy. Moreover, real-life traces can be easily used with it. Also, the user community is very helpful.

 Thank you Mr.Barun Saha. 

Mr.Nabil, Thanks lot..! Can you please provide me some study material for ONE simulator since am completely new to that tool.

There are various materials available in the Web on the ONE simulator. In fact, I do maintain the following blog, which you may find helpful.

http://delay-tolerant-networks.blogspot.com/

Much Thanks Mr.Nabil.

Thank you Mr.Barun. Will keep following.

I personally choose Omnetpp framework where I can keep a very strict control on what my code is doing. It is rather low level, but in my opinion it worth the effort.

Thanks Mr.Juan. Will try doing that.

ONE simulator is best for simulating the Delay/Disruption Tolerant Networks. It is open source. 

http://one-simuator-for-beginners.blogspot.in/2013/08/one-simulator-introduction.html

http://www.margalho.pro.br/subsites/theone.html

https://akeranen.github.io/the-one/

https://imraan-prrec.blogspot.in/ one sim