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[aprssig] Centralised message server

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Fri Nov 20 19:58:50 UTC 2009


Since you asked, I've been thinking about an APRS-IS-based message 
server that would detect messaging activity, track acks, and offer the 
sender to buffer and retry the message if too many retransmissions occur 
without an ack.  I've also considered the ability for message recipients 
to be able to set up alternate delivery addresses (like e-mail) for 
non-ack'd messages.

However, there's some (justified) resistance to "spoofed" source 
addresses on APRS packets, so the delayed delivery mechanism is a bit 
difficult to add the originator's address when the original message may 
have already been a full length.

If we can work out the behavior of such a program, and don't meet with 
much resistance, I believe it could be done similar to CQSRVR, WHO-IS, 
and EMAIL servers.

Here's a possible starting point:

1) Monitor message traffic for retries w/o acks
2) When a "longer than anticipated" delay occurs, send a message to the 
sender of the failed message.
3) Offer to a) Retry, b) Ignore, or c) Never Again the message from 
sender to receiver
4) Option would be sent via reply from sender to server (only one per 
sender/receiver at a time)
5) If c) Never Gain - add sender to "ignore" list.
6) If b) Ignore - quit processing that message
7) if a) Retry - Monitor APRS-IS for beacons from recipient and
(here's where it gets iffy)
8) Send a message to recipient from server informing of buffer message 
from sender
9) Option to a) Receive, b) Ignore, c) Never Again
10) if c) Never Again - add recipient to "ignore" list
11) if b) Ignore - quit processing that message
12) if a) Retry - Send message as if it came from original sender 
(spoofed, but with permission on both ends)

Lynn (D) - KJ4ERJ

Andrew Rich wrote:
> What do you think of the idea that you sumbit a messages to a server 
> running mysql.
>  
> Next time the station is heard, the message gets delivered ?
>  
> Like what they call a Short Message Server in mobile phones.
>  
> Would take to the necessaity off the home user to be running a client 
> holding the messages.
>  
> You would submit via the web as well through a web page.
>  
> Andrew VK4TEC
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>
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