Instant messaging and HF communications networks

There is increasing interest in expanding the use of maritime HF data communications systems to encompass IP networking and the use of IP-based networked applications such as Instant Messaging. This paper explores the ability of HF networks based upon STANAG 5066 to support such applications, and proposes performance enhancements, implemented via a proxy server, to improve the responsiveness of commercial applications when used over low bandwidth, high latency HF communications links. This paper also identifies the impact that limitations of typical system implementations have on performance, and highlights the need to minimise HF system delays to reduce the probability of collisions on the HF channel.