Bulletins from the Pacific Packet Radio Society - page 056


To: Hank
From: Den
Re: AMICON interim standard

Here are suggestions for the interim standard:

1) physical protocol

a) medium- Let's use our 15KHz unwisely for the time being, and keep an AFSK standard until better modems can be produced. We are committed to building the AMSAT 23cm linear amplifier, and should use the available 600KHz digital channel up there for low- and high- speed experiments. We are contacting other Universities who are experimenting with coding and modulation schemes, looking for the best, easiest system.

b) connection- RS-232-C is standard; also, let personal computer owners use their TNC's through whatever (parallel) scheme their TNC allows-- it matters not to the AMICON net.

2) Link Level-

a) Present and future VADCG and TAPR boards will be using HDLC; let's stick with it.

b) addressing- The present TAPR board and future VADCG boards will be using dynamic addressing, which presents no fundamental problems. The "net control" or "station node" is a very simple function which may be handled by the linking TNC. The amateur call sign is wasteful of byte-space in systems with fast turnaround times, while a single byte is all that is required for unique addressing at the local area net level. Checking into the net controller is identical to checking into the link, since they can be the same device (not required, but easy to implement). The loss of the network controller is then the loss of the link, and vice-versa, so that there is only one central point of failure, identical to the case of having no net control. The place for the amateur call sign is at the network level, so there will be no need for the transmitting station to know the binary address of the receiving station-- no bulky, global routing tables are required.

It is unfortunate that the original VADCG boards used the temporary expediency of assigning unique addresses to each board while the group was waiting for the station to station protocol to be completed. This has led to a de facto standard which will require changing all PROMS out in the field when VADCG completes their protocol. The concept of multiple ID's, common in most commercially available LAN'S, has momentarily been lost to amateur radio, and with that loss goes several simple sub-net and server access schemes.

In the opinion of most of the network TNC hardware designers,

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