[aprssig] RK3KKPK? (CONNECTED Igates?)

Andrew P. andrewemt at hotmail.com
Sun Jan 29 00:01:28 CST 2012

But connect requests aren''t sufficient to have a connection. You also have to be able to send connect accepts and rejects, connected I frames, and the DISC U frame to end a connection.

If this proposed network only supports connect requests, all it can do is half-open attacks on the receiving stations, because the receiving stations wouldn't be able to send acknowledgements or I or S frames.

Looks like the existing Igates should be renamed UIgates, because they only send UI frames (and those altered and restricted to ASCII lines).

To do what you suggest, you would need full-function AX.25 digipeaters that could route through an Internet backbone. The backbone would have to know which digipeater was the shortest route to every RF station in the world, or at least those in contact with Irouters (my name for such Internet-linked full-function digipeaters)..

That's a pretty big routing table to keep track of, especially since it changes in real-time as mobile stations move and any RF station goes on and off-line. There's no subnetting like the Internet has, because callsigns are not geographically assigned (for example, I have a KA2 prefix callsign but now live in 3-land). It's like the pre-DNS days of the Internet, with the addition of a Single Point Of Failure (SPOF): the backbone.

Maybe it's time to bring back the TCP/IP over AX.25 network that existed in the 1990's. That did have subnets that kept the routing tables at a sane size and relatively slow-changing state. Such TCP/IP networks could transparently tunnel through the Internet to avoid having to make dozens of hops through RF links; it could route through the wormholing links in the tunnels instead.

Just my $.02.

Andrew Pavlin, KA2DDO
former node in the upstate New York subnet of the ampr.org TCP/IP net
------Original Message------
From: Bob Bruninga
To: aprssig at tapr.org
Sent: Jan 28, 2012 10:11 PM
Subject: Re: [aprssig] RK3KKPK? (CONNECTED Igates?)

> Seriously, isn't that what APRS-IS is already?

No, The global APRS Internet system is for UI packets only.  There is no means of carrying a CONNECTED link from TNC A to TNC B with Igates and the internet in between.

So, why couldnt we?  Of course one objection is the one we see here about security and control of packets sent back to RF via an IGate.  But, if we only allowed CONNECTIONS, and no UI packets on this other APRS-CONNECTED channel, then nothing could be forced out of a remote IGate back to RF except connect-requests.  No one could force inappropriate packets in the blind.

If a valid connection is established, then the CONNECTED-TO station would bear the responsibility for the traffic.

Just thinking outside the box.

Bob, Wb4aPR

>On 1/28/2012 8:45 PM, Bob Bruninga wrote:
>> Come to think about it, have I been asleep?  Why couldn't we have an IGate system on 145.01 all over the USA linked into an IGATE system so that everyone's TNC was only a one-hop CONNECT away from any other TNC in the world?
>> We could call it APRS-CONNECT on 145.01 (if it has not been taken over by a DX cluster)...
>> Bob, WB4APR

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