NS2 Question

[Rajesh Krishna Balan <rajeshkr@comp.nus.edu.sg>]

I have the following question about NS2 and i am unable to figure it out.
I hope you can help me with this query. Any help provided would be much
appreciated. :)

The question is as follows.

My group wants to look at the effect of TCP tunnels. i.e. we encapsulate
tcp packets within another tcp packet. It's similar to IP tunnels but we
are doing it 1 layer higher.

Is there an easy way in NS2 to support this encapsulation? i ask because
the basic TCP code has no concept of real data and uses numbers to
represent data lengths. This is fine for most uses but in our case, we
will need to preserve the actual encapsulated header which is the "data"
of the big tcp packet. i.e. the packet which is encapsulating another tcp
packet.

I was thinking of modifying the tcp code itself but that has proved to be
difficult as i wasn't sure that what i ended up with at the end was still
tcp. 

Is there an easy way to support this header encapsulation. The only "data"
we are interested in is the encapsulated header. 

A pointer to an example would be very much appreciated. :)

Thank you very much.

Rajesh