Warren Toomey VK1XWT
Lawrie Brown VK1KLB
DEPARTMENT OF COMPUTER SCIENCE
THE UNIVERSITY OF NEW SOUTH WALES
AUSTRALIAN DEFENCE FORCE ACADEMY
Fri Feb 10 12:58:13 EST 1995
Technical Report CS01/95
The standard amateur packet radio protocol, AX.25, provides the end-user with a virtual circuit interface to the link layer, while implementing this using packets, and using a CSMA medium access control mechanism. This paper suggests that the link layer in this application area should be separated into 3 layers (LLC, MAC and Physical Layer), and a set of modular protocols for each part be designed for amateur radio use. A new simplified Logical Link Control layer, DUAL, is described, which is not only more suitable than AX.25 for the transmission of higher-layer traffic, but also more bandwidth-efficient. This is achieved by using link layer addresses tailored to the network protocol used, minimizing the link layer overheads, and by incorporating a modified IP header compression scheme adapted for use in a multi-point environment.