Evaluation of a DTN Convergence Layer for the AX.25 Network Protocol

The AX.25 Link Access Protocol for Amateur Packet Radio is a data link layer protocol derived from the ITU-T X.25 data link protocol with modifications for use by amateur radio operators. One of the authors has produced a prototype AX.25 connected mode DTN Convergence Layer (CL) based on the existing DTN2 reference implementation. Initial testing of this implementation was undertaken on Linux in order to compare the performance of the implementation with the performance of native AX.25 links. Initial results appear to indicate that the current prototype can be up to 25 percent more efficient than using the Linux TCP/IP over AX.25 implementation in certain circumstances. The experimental results also reveal situations where obvious improvements can still be made to the implementation.