readme.txt

ns-2 simulation code manet

Cross-layer Interaction in Multihop 802.11 Networks
(TCP FeW and DSR++)


Kitae Nahm  [e-mail]
Ahmed Helmy [e-mail]
C.-C. Jay Kuo   [e-mail]

Department of Electrical Engineering
Viterbi School of Engineering
University of Southern California


1. Introduction

This package includes two mobile ad hoc network (MANET) subpackages for NS-2.29. One is TCP FeW,
and the other is DAMPEN policy for DSR protocol. These schemes are propose to suppress the
inefficient cross-layer interaction among TCP, dynamic routing, and medium access control of
IEEE 802.11, which leads to improvement of TCP performance and routing stability. More information
about these schemes can be found in

http://biron.usc.edu/~nahm/research.htm


2. DSR++ (DSR with DAMPEN policy) package

- The maximum end-to-end hop distance supported by DSR agent is changed from 16 hops to 50 hops
- A new command "add-route" that provides a manual configuration of source route is added
- DAMPEN policy with beta-factor is implemented for DSR protocol

tcl/lib/ns-default.tcl - Initiating beta factor and other monitoring variables
tcl/mobility/dsr.tcl - Adding "add-route" command for manual path configuration in DSR protocol
common/packet.h - Adding a new 802.11 MAC message "XMIT_REASON_CONFIRM" for a callback function
mac/802.11.cc   - Adding callback function to routing agent when Tx is succeeded
dsr/dsragent.h  - Adding beta factor to control DSR's sensitivity to link failure
dsr/dsragent.cc - Adding beta factor to control DSR's sensitivity to link failure
dsr/hdr_sr.h    - Changing the maximum end-to-end hop distance allowed by DSR agent

3. TCP FeW (fraction window increment) package

- The alpha-factor of FeW scheme can be controlled via variable "increase_num_".
- FeW scheme is primarily for low bandwidth-delay product networking environment, so slow start is de-activated for alpha<1.
- Monitoring functions are added: event tracing in "tcp.cc"; throughput tracing in "tcp-sink.cc" and "tcp-sink.h" which is included in the separate simulation package.

tcp/tcp.cc - FeW support and event tracing


4. Usage

- Uncompress the package in the NS-2.27 directory and replace the source code. Then, 'make' in NS-2.27 directory.
- Alpha factor (TCP FeW) can be controlled via TCP variable "increase_num_" (existing in NS-2.27)
  1: TCP default    less than 1: TCP FeW
- Beta factor (DSR) can be controlled via DSR variable "beta_" (new in this package)
  0: Static routing 1: DSR original   2: default in this package   3 or greater: supported
- Manual static routing can be tested using DSR++ and a new command "add-route"
    1) Format: "$node_( [a node id] ) add-route [path: a list of node id's]"
    2) Example: $node_(0) add-route 0 1 2 3 4 5   (DSR agent at node id 0 has a pre-configured path from node id 0 to node id 5 via node 1, 2, 3, 4)

- For simple test, a simulation package is separately available at http://biron.usc.edu/~nahm/research.htm

5. History
- June 12, 2005: First uploaded for ns-2.27
- October 2005: Upgraded for ns-2.29
- July 4, 2006: 1) "Event UID not valid" bug fix based on Federico's report ( http://www.dei.unipd.it/wdyn/?IDsezione=2435 )
                2) "add-route" command for manual path configuration