[aprssig] A few clarifications for a club APRS presentation, Please

Tapio Sokura oh2kku at iki.fi
Sat May 24 09:49:24 EDT 2008


Steve Noskowicz wrote:
> Regular Packet:
> 1 - Must address specific stations.
> 2 – Must also specify specific digis.
> 3 – Must specify the complete path (*all* station/digi names) to reach a
> distant station.
> 4 – Must "connect" (verify with a two way exchange) with a station to transfer
> traffic.

This is a minor detail, but there are automated routing systems that are 
(or have been) used for regular packet. Some of the most common ones are 
net/rom, rose, and flexnet. Basically you first connect to a node that 
participates in that routing system and tell it the end node you want to 
connect to. If the system knows how to reach the end node, it 
transparently relays your packets, with acks/retransmissions. I'm not 
talking standard digipeating here. These routing systems are built on 
top of basic AX.25.

You can also exchange unconnected/unnumbered information frames in 
regular packet, but typically they were only used for things like 
announcing you are on the frequency (beacons) and broadcasting who has 
new mail in a given BBS. Some routing systems also rely on regularly 
broadcasting their node lists for routing information propagation.

   Tapio




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