Re: Need comments.. T.T

[Kannan Varadhan <kannan@ISI.EDU>]

> From: yongsin kim <dragon@dcn.soongsil.ac.kr>
> Date: Tue, 16 Jun 1998 12:57:29 +0900

> Hello All.
> 
> Topology : 
> 
> (tcp)  S  --------- R -------- K (tcp sink)
> 
> 
> If i want  addtional 'method' in [Node R], what is solution?
> Very importantly, 'method' has bidirectional property.
> (i.e 'R' save packets from 'S', and  delete saved packets when receve 'ack'
> from 'K')
> 
> It's so difficult to solve.

yongsin kim,

YOu might take a look at the snoop work in ns to see if it
has a solution to your problem.  Hari was looking at similar
problems.

Alternately, you have to do some minimal amount of coding.
You'd have to code two objects, derived from the Connector
class---one object, call it FWD, is placed on the R->K link,
the other, call it REV, to process packets in the reverse 
direction.  You have to code the pieces in OTcl to tie these
two objects together; you have to code the recv method in FWD
to do the kind of things you require, i.e. save packets in
your example; the recv method in REV will likewise process
packets in the reverse direction---quite likely, in your caes
it will simply pass the received packets to FWD, so FWD
can delete the appropriate packets, and then send the packet
to its target.

The various details that you'd need in order to do this
coding are in the ns Notes and Documentation, available
at http://www-mash.cs.berkeley.edu/ns/nsDoc.ps.gz.


Kannan

--
kannan@isi.edu
http://www.isi.edu/~kannan