Re: [ns] Problems using TcpApp wit FullTcp

[Tarik Alj <aljtarik@inrs-telecom.uquebec.ca>]

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argh, got caught!

here it is :

>I'm not sure this is going to fix your problem, but it will help. reset is
>partially broken in FullTcp. The main problem is that closed_ is defined in
>tcp.h and then redefined in tcp-full.h. This *is* wrong. I submitted a bug
>report three month ago, but it has not been committed yet. Read my (lengthy)
>posting for more details,
>
>http://www.isi.edu/nsnam/archive/ns-users/webarch/2000/msg03812.html
>
>(see also John Heidemann's reply:
>http://www.isi.edu/nsnam/archive/ns-users/webarch/2000/msg03859.html)
>
>You may want to contact Tarik Alj (aljtarik@inrs-telecom.uquebec.ca). He was
>doing real work with FullTcp at that time, while I was just trying to help. He
>may have a more mature version of FullTcp.

I wish I did! As a matter of fact I have been using the FullTcp version I got 
from Felix and it has been working alright for me.

You might want to try and run gdb to see if TCP is in the right "STATE" after 
reset. I think there might also be a problem when "connecting" the agents 
together, I would look into the behaviour there. 

Anyways this code is messy, there must be a few bugs just waiting to be stumbled 
across... If you find more keep us posted!


>
>By the way, someone with writing access should have a look to this and make 
some
>changes. Thanks.
>
>Mark Janssen wrote:
>
>> Hello all,
>>
>> I am trying to use TcpApp over FullTcp to simulate some application
>> behaviour. While doing that I run into a problem while connecting different
>> apps. What I would like to accomplish is the following:
>>
>> I have a linear topology of three nodes with an attached FullTcp agent:
>>
>> (1)-----------(2)-----------(3)
>>
>> After that I create three apps and put the TCP agent at the second node in
>> the listen state. And connect tcp1 with tcp2 with app1 and app2.
>> Now app1 sends a message to app2. This all works great. Now because of this
>> message app2 needs to contact app3. So I connect tcp2 with tcp3 and app2
>> with app3 and I put tcp3 in listen mode.
>> When I now send a message from app2 to app3 I only see ACK packets without
>> TCP packets. I suspect this occurs because tcp2 is still in a different
>> state then when you create it. I tried to do a "$tcp2 reset" but that
>> doesn't solve my problem. Below I have include the tcl script, the ns output
>> and the tracefile.
...

>> $ns connect $tcp1 $tcp2
>> $app1 connect $app2
>> #Call the finish procedure after 5 seconds of simulation time
>> $ns at 0.1 "$tcp2 listen ;  $app1 send 100 \"$app2 app-recv $app1 100\""
>> $ns at 4.0 "$ns connect $tcp2 $tcp3 ; $app2 connect $app3; $tcp3 listen;
>> $app2 send 100 \"$app3 app-recv $app2 100\""
>> $ns at 7.0 "finish"
>> #Run the simulation
>> $ns run
>> ###end tcpapp.tcl
>>
...
-Tarik