-
8/6/2019 Aloha netwinz Guide
1/5
netwinz
ALOHA
Introduction:
ALOHAnet, also known as the ALOHA System, or simply ALOHA, was a
pioneeringcomputer networking system developed at the University of
Hawaii. ALOHAnet
became operational in June, 1971, providing the first
demonstration of a wireless
data network.
The ALOHAnet used a new method of medium access (ALOHA random
access)
and experimental UHF frequencies for its operation, since
frequency assignments
for communications to and from a computer were not available for
commercial
applications in the 1970s. But even before such frequencies were
assigned there
were two other media available for the application of an ALOHA
channel cablesand satellites. In the 1970s ALOHA random access was
employed in the widely
used Ethernet cable based network and then in the Marisat (now
Inmarsat)
satellite network.
"Slotted ALOHA", introduced discrete timeslots and increased the
maximum
throughput. A station can send only at the beginning of a
timeslot, and thus
collisions are reduced. In this case, we only need to worry
about the transmission-
attempts within 1 frame-time and not 2 consecutive frame-times,
since collisions
can only occur during each timeslot.
netwinz Guide
-
8/6/2019 Aloha netwinz Guide
2/5
HOW TO CONDUCT THE EXPERIMENT:
Click on Network Layer on the Main Window and Then Select ALOHA
Module
from the Modules displayed in the centre of the window.
AOHA Window will open up as shown in SNAPSHOT-1.
SNAPSHOT-1
STATION:
1. Enter Ip Addresses of all the computers that will run as
ALOHA nodes.
2. Click on START STATION button to start the Aloha Station.Note
that only one computer can run the station. Any duplicate station
will
not be allowed.
Wait for the station to successfully start.
3. Click on STOP STATION if you want to stop the Station.
-
8/6/2019 Aloha netwinz Guide
3/5
COMMUNICATION NODE:
1. Click on SEARH Button to search for stations. Wait for the
search to
complete.
The station IP Address will be displayed in the STATION textbox
as shown in
SNAPSHOT-2
SNAPSHOT-2
2. Enter message in the MESSAGE textbox.
3. Enter the Slot on which the message will be transmitted in
the SLOT
textbox. Valid Slot is from 0 to 9.
4. Click on SEND button to send the Message.
-
8/6/2019 Aloha netwinz Guide
4/5
After you click on SEND button, the node will listen to the beep
signal
from the station representing slots and will display the same in
the
CURRENT SLOT text box. When the Slot entered by you matches
the
CURRENT SLOT the data is sent. See SNAPSHOT-3
Start Multiple Communication nodes and try sending messages from
some
communication nodes on the same slot.
Collisions will occur where ever more than one node tries to
send on the
same slot and same is updated to the corresponding nodes as well
as the
station.
SNAPSHOT-3
Messages are Displayed in the Message Window on the extreme
right.
Reset Button:
-
8/6/2019 Aloha netwinz Guide
5/5
Click On RESET BUTTON to reset all the controls to initial
values.
Click on HELP BUTTON to Open this Manual.
Click on EXIT BUTTON To Close this Window.
Copyright 2011 Emblitz Technologies Pvt Ltd. All rights
reserved.www.netwinz.com
http://www.netwinz.com/http://www.netwinz.com/http://www.netwinz.com/http://www.netwinz.com/
