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TCP WESTWOOD - Modules for NS-2

In this page you can find the TCP Westwood Modules for the NS-2 network simulator.

TCP Westwood modules for NS-2 come in two flavors:

• TCP WestwoodNR (TCP Westwood based on TCP NewReno) with installation instructions
  (we suggest to use TCP WestwoodNR and compare it to the NewReno protocol)

• TCP Westwood (TCP Westwood based on TCP Reno) with installation instructions

Other material:

• Instructions to make TCPW modules compatible with future versions of NS-2

• Older source code

Support:

For any question about the NS-2 code, please contact: tcpw-support@cabernet.cs.ucla.edu?

TCP WestwoodNR (TCP Westwood with NewReno features)

NS-2 Modules

• tcp-westwood-nr.cc (for NS-2 version 2.1b8a only; see the COMPATIBILITY NOTES if you use other versions of NS-2)

• tcp-westwood-nr.h

Installation Instructions

1. Get NS-2 version 2.1b8a

2. Add the modules tcp-westwood-nr.cc and tcp-westwood-nr.h to the main NS-2 directory (which is something like: ../ns-allinone-2.1b8a/ns-2.1b8a)

3. Modify the Makefile so that it compiles and links the new module (i.e. add tcp-westwood-nr.o anywhere in the OBJ_CC? variable, for example near the other TCP related modules like tcp-newreno.o or tcp-vegas.o).?You can find the Makefile under the main NS-2 directory

4. Add the following lines to ns-default.tcl (it can be found in the tcl/lib directory of the main NS-2 directory):

   # Added for TCP WestwoodNR Agent/TCP/WestwoodNR set current_bwe_ 0 Agent/TCP/WestwoodNR set last_bwe_sample_ 0 Agent/TCP/WestwoodNR set unaccounted_ 0 Agent/TCP/WestwoodNR set fr_a_ 1 Agent/TCP/WestwoodNR set min_rtt_estimate 10000 Agent/TCP/WestwoodNR set myseqno_ 1 Agent/TCP/WestwoodNR set lastackno_ 0 Agent/TCP/WestwoodNR set lastackrx_ 0 Agent/TCP/WestwoodNR set fr_alpha_ 0.9 Agent/TCP/WestwoodNR set filter_type_ 3 Agent/TCP/WestwoodNR set tau_ 1.0 # setting this to 1 implements some changes to reno? # proposed by Janey Hoe (other than fixing reno's # unnecessary retransmit timeouts) Agent/TCP/WestwoodNR set newreno_changes_ 0 # setting this to 1 allows the retransmit timer to expire for # a window with many packet drops Agent/TCP/WestwoodNR set newreno_changes1_ 0 Agent/TCP/WestwoodNR set partial_window_deflation_ 0 Agent/TCP/WestwoodNR set exit_recovery_fix_ 0

   ?
   
5. Recompile NS-2

COMPATIBILITY NOTES for TCP WestwoodNR modules

1. The tcp-westwood-nr.cc and tcp-westwood-nr.h files provided here have been tested with NS-2 version 2.1b8a only. We have not tested the implementation with other versions. Please report any incompatibility to tcpw-support@cabernet.cs.ucla.edu
2. If you are using NS-2 version 2.1b6 then you MUST use this file: tcp-westwood-nr.cc.V21b6 instead (put it the main NS-2 directory and rename it to tcp-westwood-nr.cc, then recompile NS-2)

TCP Westwood

NS-2 Modules

• tcp-westwood.cc (for NS-2 version 2.1b8a only; see the COMPATIBILITY NOTES if you use other versions of NS-2)

• tcp-westwood.h

Installation Instructions

1. Get NS-2 version 2.1b8a ?
2. Add the modules tcp-westwood.cc and tcp-westwood.h to the main NS-2 directory (which is something like: ../ns-allinone-2.1b8a/ns-2.1b8a)
3. Modify the Makefile so that it compiles and links the new module (i.e. add tcp-westwood.o anywhere in the OBJ_CC? variable, for example near the other TCP related modules like tcp-newreno.o or? tcp-vegas.o).?You can find the Makefile under the main NS-2 directory
4. Add the following lines at the end of ns-default.tcl (it can be found in the tcl/lib directory under the main NS-2 directory):

5. # Added for TCP Westwood Agent/TCP/Westwood set current_bwe_ 0 Agent/TCP/Westwood set last_bwe_sample_ 0 Agent/TCP/Westwood set unaccounted_ 0 Agent/TCP/Westwood set fr_a_ 1 Agent/TCP/Westwood set min_rtt_estimate 10000 Agent/TCP/Westwood set myseqno_ 1 Agent/TCP/Westwood set lastackno_ 0 Agent/TCP/Westwood set lastackrx_ 0 Agent/TCP/Westwood set fr_alpha_ 0.9 Agent/TCP/Westwood set filter_type_ 3 Agent/TCP/Westwood set tau_ 1.0

6. Recompile NS-2

COMPATIBILITY NOTES for TCP Westwood modules

• The tcp-westwood.cc and tcp-westwood.h files provided here have been tested with NS-2 version 2.1b8a only. We have not tested the implementation with other versions. Please report any incompatibility to tcpw-support@cabernet.cs.ucla.edu

Instructions to make TCPW modules compatible with future versions of NS-2

To make the TCPW modules compatible with future versions of NS-2 just do the following:

• Get the new version of NS-2
• Delete the old WestwoodTcpAgent::slowdown method that is inside tcp-westwood.cc
• Copy the TcpAgent::slowdown(int how) method from the new tcp.cc into the file tcp-westwood.cc renaming the method WestwoodTcpAgent::slowdown(int how)
• Put the following code between the conditions:
  
  else if (how & CWND_HALF_WITH_MIN) {...}
  and
  else if (how & CLOSE_CWND_RESTART)
  
  This is the code you have to insert:

///
	else if (how & CLOSE_FASTER) {
    	// TCP Westwood
	// this might be critical what with the coarseness of the timer;
    	// keep in mind that TCP computes the timeout as
    	//              (#of ticks) * (tick_duration)
    	// We need to do away with the coarseness...

• Now you have a new tcp-westwood.cc module that should be compatible with the new version of NS-2
• Follow the installation instruction earlier in the page using this new module

Older source code

• previous version of modified TCPW (with the "idle_interval bug"): tcp-westwood.cc, tcp-westwood.h

• original TCP Westwood files from Casetti (to be used with NS-2 version 2.1b6):

  • tcp.cc

  • tcp.h

  • tcp-westwood.cc

  • and original Casetti's TCPW page

• tcp.cc and tcp.h source files from 2.1b6 NS-2distribution