Summer 2006 Issue

HSMM

The Hinternet and VPN Projects

By John Champa,* K8OCL

 

 

 

Figure 1. The HSMM Virtual Private Network test system.

One of the stated objectives of the ARRL HSMM Working Group is the creation of the “Hinternet,” an amateur-radio-run network that has capabilities similar to those of the internet and can operate as an alternative to it. This aim harks back to the original ideas of the creators of ampr.net in the early to mid ’70s The general guiding principle in this effort is the pervasive use of radio as the “physical layer” of the network. This is, after all, an amateur radio pursuit.

The current work of the HSMM Working Group has some very distinct implications when considered against the goal of spanning the globe. As an example, the most common network technology under evaluation, 802.11b, is practically useful inside a quarter mile unless using high towers and directional antennas, which extend the range to less than 15 miles, or maybe up to 30 miles with very carefully applied antenna work and a bit of luck.
The HSMM OFDM modem currently under development by the Working Group has the potential to be used in several of the existing amateur bands. One of these is UHF, where the OFDM modem, if it is anything like regular FM voice, will likely be able to cover somewhere up to 100 miles. There may be flash improvements from tropo-ducting and other similar phenomena, but always-up network reliability can’t be based on transient effects like that. Another exciting possibility is the use of the OFDM modem on the 6-meter “Magic Band.” However, it should be remembered that 6 meters, while good at times, is quite decidedly dead at other times.

The bottom line is that these methods currently being pursued are locally reliable, but over long distances they are spotty at best. To practically extend a network around the world, some other type of link is required—at least until a good long-distance RF method arrives that provides fat bandwidth around the planet, for example an AMSAT Phase III or Phase IV satellite. That link is secure, easy-to-use tunnels through the internet. Such connectivity would tie our various experimental efforts into one big, planet-spanning network, which we could begin to use for things such as message passing, digital group chats, voice/video conferencing, emergency communications, and other possible uses as we come up with them.

Guidelines for the Hinternet
Simple—This is for use by radio amateurs. Only some are computer/network geniuses. Wide use will require usability by more than the comp/net people.

Affordable—Should use cheap (but good) hardware, or “already have it” hardware. Should, where possible, leverage free software.

Dynamic—Should be able to adapt to a constantly changing network, with parts of it going online and offline. Realistically we are not carrier-grade NOCs. We are hobbyists. We won’t have SLAs on our networks or HA setups that are always there.

Interoperable—Where possible, we should support most (if not all) of radio amateurs’ favorite platforms. Practically, this would be Windows®, MacOS®, and Linux. If done correctly (i.e., simple bootable CDs or USB keys), this requirement virtually disappears, and the connecting system becomes just another “rig.”

Secure—We should be able to leverage quality crypto to keep the tunnel part of our network scrambled and protected while traversing the public internet, and it should be done easily.

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