The document discusses a wireless access research project involving automated file transfer between nodes. Shell scripts using SSH and SCP commands transfer files and execute commands securely between nodes. A GUI allows limited interactivity by invoking scripts to fetch results from remote nodes. The software represents physical nodes and their attributes as Node objects within an array. It also graphically displays the network topology based on routing tables, updating periodically.

1. Wireless Access Research
Adil Raja July 2005
ULMAN-GUI

2. Wireless Access Research
Adil Raja July 2005
Node Status Files
• Status files of a node relevant to a particular module are
kept in a sub-directory pertaining to the that module.
• This sub-directory is placed under the ULMAN-GUI’s
Home directory.
• The files received by each node are prefixed with their
node names.
• For example, the tethereal log file obtained by node1 is
stored as follows.
~/ulman_gui/tethereal/node1_ethdump.log

3. Wireless Access Research
Adil Raja July 2005
Automated File Transfer
• Shell scripts containing OpenSSH suite’s SSH and SCP
commands are used for automated command execution
and file transfers.
• Advantages: -
 Security: - Encrypted exchange of data (including password)
between communicating nodes.
 OpenSSH is a free software.
• Disadvantages: -
 We cannot have a long term session established with the nodes:
The scripts establish a connection, run the appropriate
command, display the result and close the connection.
 Lack of Interactivity.

4. Wireless Access Research
Adil Raja July 2005
Automated File Transfer
• The limited interactivity with the nodes shall be achieved
by invoking shell scripts from the GUI (with the help of
buttons).
• The shell scripts will execute appropriate commands on
the remote nodes and fetch the results back to controller
node.
• The GUI software can then perform I/O redirection on
the fetched results to display them on the GUI’s shell, or
do further processing with it.

5. Wireless Access Research
Adil Raja July 2005
Software Design Issues
• The software has a Node object.
• The attributes of a physical node are
represented by the variables of the Node
object.
• As a result, the physical nodes and their
attributes are represented by an array of
Node objects in the GUI software.

6. Wireless Access Research
Adil Raja July 2005
Elements of the Node Object
• Control IP Address of the Node.
• Wireless IP Address of the Node.
• List of Next hops (destinations?).
• Some variables relevant to the software.

7. Wireless Access Research
Adil Raja July 2005
User Requirements…..
• Given a total number of N wireless nodes
in the network, the user should be able to
include any K (where 0<K<=N) of them in
a test.
• For these K Nodes the user should be
able to invoke a variable number of output
consoles.

8. Wireless Access Research
Adil Raja July 2005
Network Topology – Graphical View
• The routing tables of all the nodes are
used to draw a graphical view of the
current network topology.
• The wireless nodes are represented by
vertices in the graph.
• The link between a node and its next hop
is represented by an edge between these
nodes.

9. Wireless Access Research
Adil Raja July 2005
Network Topology – Graphical View
(Continued …..)
• The network topology is updated after
short intervals of time to depict the true
picture of the network.
• The time interval (for updating) the
network topology may depend on the
frequency of routing table updates OR as
to how often the user requires to view an
updated image of the network.