Bulletins from the Pacific Packet Radio Society - page 050

This represents AMRAD's thinking toward the AMICON interim standard that you are now drafting. It also gives you our thoughts on local area and backbone networking issues.

Communications Channel

We have no problems with the ideas expressed on the telecon. Virtually everyone who is active on packet radio today is using the VADCG TNC, Bell 202 modems to afsk a vhf-fm transceiver with 5-kHz deviation and about 15-kHz rf bandwidth. Unless we stick with these parameters for the communications channel, the packet people will be hard-pressed to reconfigure by the time that Oscar Phase III-B is launched. It is a bit wasteful of bandwidth (as opposed to fsk), but that is a trade-off to allow people to use their pre sen t equipment.

Physical Level

The re do no t appear to be any issues at this level. Everyone in North America is using RS-232-C, and others may use X.21.

Link Level

The link level protocol, in our view, is essentially non controversial, at least to the extent that there appears to be a consensus for using HDLC. The main issue here is addressing. There may be some issues concerning the control field, but these are secondary and can be deferred for now.

Dynamic vs. Static Link-Level Addressing

We are fundamentally opposed to dynamic addressing at the link level. One of the strongest reasons is that each individual amateur packet radio station should be able to come on the air at link level and use his TNC board to connect without having to check into a particular network controller to find out his address. He already has one (his call sign), and we see no reason to avoid using it for link-level addressing. This permits an anarchistic mode of communications, and permits operation whether or no t there is a network controller present. The ability to communicate after loss of a network controller is vital to emergency communications. It may be key to our being able to stay on the air after a nuclear attack. (Right now, that's against the law. The case is being made now to the DoD that Amateur Radio can survive and that the law should be changed to permit post-attack operation. If the packet net is designed to survive, we have some chance of getting some DoD funding. In our view, the prospects of DoD funding are not at all certain and should not be the driving force.)

The details of our argument for static call sign link-level addressing and against dynamic addressing are spelled out in Terry Fox's article, "Level 2 Protocol Proposal," which appeared

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