ALOHA

What Does ALOHA Mean?

ALOHA was a pioneering networking system developed at the University of Hawaii in 1971 as a first demonstration of wireless networks. It used a medium access method along with experimental UHF frequencies.

Advertisements

ALOHA served as the basis for the development of Ethernet and Wi-Fi networking.

This term is also known as ALOHAnet.

Techopedia Explains ALOHA

The concept of ALOHA emerged when frequency assignments for communications between computers were not available for commercial applications.

The initial version of ALOHA used two different frequencies in a hub configuration. The hub machines were used to broadcast packets to all outbound channels and to different client machines. Upon receiving error-free data at the hubs, an acknowledgment packet was sent to the clients. If no acknowledgments were received, data packets were retransmitted after a selected time interval. This mechanism detected and corrected collisions when two clients attempted to send packets at the same time.

All client nodes in ALOHA communicate with the hub using the same frequency. The shared use of a single medium for client transmissions was critical. A mechanism was used for controlling packet sending, resending and collisions. This was called pure ALOHA, or random access channel, and served as the basis for the development of Ethernet and Wi-Fi networks. It also was used for the outgoing hub channel, allowing broadcast packets to be sent to all clients on a second shared frequency where each client recipient has its own address.

Advertisements

Related Terms

Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.