1. Measuring the performance of a Wireless network

note throughout the following tutorial the courier font indicates the terminal output
- whereas the courier bold indicates keyboard input.
- and italic indicates some thought is necessary in order to enter text
login to a GNU/Linux client
- open up two terminal windows and arrange them side by side
in the left hand window login to j135-cluster.comp.glam.ac.uk using ssh
- then login into to 192.168.0.254 and then to 192.168.1.2
do this by typing:

$ ssh j135-cluster.comp.glam.ac.uk
Password: yourpassword
$ ssh 192.168.0.254
Password: yourpassword
$ ssh 192.168.1.2
Password: yourpassword

in the right hand window login to j135-cluster.comp.glam.ac.uk and then 192.168.0.254

$ ssh j135-cluster.comp.glam.ac.uk
Password: yourpassword
$ ssh 192.168.0.254
Password: yourpassword

from your brower download this: performance monitoring tools
and using the file manager move this downloaded archive into your home (or your top level) directory
unpack the archive by typing these commands into your right hand terminal window

$ tar zxf performance.tar.gz
$ cd performance

in the left hand window on 192.168.1.2 type:
```
$ cd performance
```
to run these performance tests you need to have changed to the performance directory

2. Testing the performance of Wireless Linux NFS

in the client window (right hand window) type:

$ ./sendnfs
gcc -O2 -g -o bin/‘arch‘/send send.c
gcc -O2 -g -o bin/‘arch‘/rec rec.c
gcc -O2 -g -o bin/‘arch‘/sendnfs sendnfs.c
You should be on an NFS mounted directory - check mcgreg ...
Filesystem           1K-blocks      Used Available Use% Mounted on
etc etc etc

the command ./sendnfs writes many blocks across the network file system to the server and reports the speed
- if the experiment runs too quickly or too slowly increase or decrease the value of the constant in the file: sendnfs.c
- alter the line 5
- #define NBYTES (64*1024*10)
- to a number 10 times larger or smaller depending on the speed
once you have made a change to the source code you need to type this command into the right hand window:
```
$ make clean
```
when you get some interesting results you should capture the output of this test for your coursework

3. Wireless Linux TCP Performance

in the left hand window on 192.168.1.2 type:

$ ./tcprec
The receiving host is: 192.168.1.2, \
   the port is 7000, the protocol is -tcp

this confirms the host which will receive the tcp packets and it also tells you the tcp socket port number, in this case 7000
now on the right hand window type:
```
$ ./tcpsend 192.168.1.2 7000
```
note the sender and receiver port number must match
- in this case it was 7000 but yours might vary
you should see output similar to this appear in your right hand window:

$ ./tcpsend 192.168.1.2 7000
time to send     10 blocks of 67108864 bytes is 1.738 seconds
time to send     20 blocks of 33554432 bytes is 1.736 seconds
etc etc etc

if you find the experiment taking too long then alter line 18 of the file send.c , which is:
```
#define NBYTES       65536*1024
```
and divide this number by 8, or 16, (ensure that the divisor is a factor of 2)
after modifying your test be sure to press <ctrl> C in both the right hand window and the left hand window
- <ctrl> C terminates any test program
also after any code modification type:
```
$ make clean
```
in the right hand window
when your test has finished be sure to press <ctrl> C in both the right hand window and the left hand window

4. Wireless Linux UDP Performance

these performance results can be obtained by following the TCP performance instructions and altering every occurance of tcp with udp
the only significant difference is that UDP ignores errors and therefore the receiving side displays actual data received and the transmitter displays actual data sent

Index

1. Measuring the performance of a Wireless network
2. Testing the performance of Wireless Linux NFS
3. Wireless Linux TCP Performance
4. Wireless Linux UDP Performance
Index

This document was produced using groff-1.19.