You can set the queue length through the ifqLen in node-config:

$ns_ node-config -llType LL

-ifqType "Queue/DropTail/PriQueue"

-ifqLen 50

-macType Mac/802_11

-phyType "Phy/WirelessPhy"

-addressingType flat

-adhocRouting DSR or DSDV

-propType "Propagation/TwoRayGround"

-antType "Antenna/OmniAntenna"

-channelType "Channel/WirelessChannel"

-topoInstance $topo

-agentTrace ON

-routerTrace ON

-macTrace OFF

-movementTrace OFF

What do you mean by delay in routing algorithm?

I recommend you to go through this tutorial, I hope this will help you. 

http://myns2work.blogspot.com/2012/12/tutorial-to-implement-protoname-in-ns235.html

All of you want is in this document:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CB0QFjAAahUKEwik-J_X9_DHAhXD1RQKHW6ZBHk&url=http%3A%2F%2Fwww.isi.edu%2Fnsnam%2Fns%2Fdoc%2Fns_doc.pdf&usg=AFQjCNE1LnDO8YQtjuH6UmGLbPYDgmf5fw&sig2=zfp9a8aU0vCvnxdNCbtHuQ&bvm=bv.102537793,d.d24&cad=rja

This is a good doc for ns.

Dear,

Please follow the steps:

First of all you have to learn the structure of NS2 very well i.e you have to know how it work.

Then you have to learn  very well how to configure node of a network using TCL code. What parameter should you change to deploy your thinking in the networrk( like queue length, tcp agent CBR, VBR, congestion control, req queue management etc.) These steps may be enough for a simple analysis type work.

But if you  want to show some changes in the protocol then you must have to be master in C++  and also have to know which code module is used for which functionality. If you understand very well then proceed further to implement the changes you are thinking that should be for improvement. Then please change the corresponding configuration TCL file supporting to run the protocol.

Finally recompile the code. 

>> ns your_dersired_protocol.tcl

If you get some data from the network you design then compare the data with previous by using Ploting tool( I prefer GNU plot or excel). But run the procol atleast three times and make an average to get the desired result because result may be different from one another. so we consider average is the closest approximation.

May be this tips are helpful for you  :)

Thanks.

thanks sir for your reply, i know c++ but can you suggest a book for learning how to change parameter in  tcl  ar any reference for that?

please suggest

thanks a lot ..

I attached a pdf book for your reference. Hope it will help you to learn NS-2 and TCL, etc. 

Thanks sir .well can you suggest devising new routing protocol can be related to PhD topic.I have to start up with PhD problem definition.

It is depend on you and your study background, that which layer protocol you will select for your PhD topic. If you need any further assistant so pm me. 

thanks sir for your concern.

Sir i had done  performance evaluation of routing protocols and now i am working on congestion control .but i am facing problem in implementation on ns2. i want to learn it .Can you give me description of how i can master it?

Dear Aarti Bansal,

You dont have to go far to be expert with NS2 or NS3. When you successfully install the simulators then in the DOC directory you will get a NS@2 & 3 official manual which is the best documentation for these simulators.

Aslo you can watch youtube to find some useful information.

Best of luck with your research.

This is a good reference on ns-2: http://www.springer.com/us/book/9780387717593.

Thanks sir , it seems that this book is worth referring but its nt available at low price edition.is there any other way out to read it.

In which layer you want effect a congestion control ? Routing or MAC?

In Routing layer

hello all i want to modify aodv by varying its queue length.any one can help me out?

What do you want to modify? Do you want to ckeck effect of queue length on aodv?

If you just want set the queue length you can add this code in your program in the definitions:

set opt(ifq) Queue/DropTail/PriQueue ;# interface queue type

set opt(ifqlen) 50 ;# max packet in ifq

In this example we create a queue with the length of 50 and the queue is droptail means if the packets in queue is greater than 50,will dropped...

OK?

i want to apply or divert route scheme if queue length  limit is reached. how those changes can be made in the code?

If you want to handle an event such as reaching the queue length and do an action after that you should create an event handeler.This link will be usefull for knowing event handeler:

http://www.slideshare.net/TBear76/ns2-events-and-handlers

and this link,too:

http://www.isi.edu/nsnam/ns/doc/node32.html

you may increase the efficiency by running the non-dependent processes parallel.

Pls suggest non dependent processes that can be taken? And how