David,
I'm only Cisco IOS literate with a manual in hand :) but I see the
appeal of the reuse of IP protocols. I just think it confuses the
issue in D-STAR
I feel the callsign (including the 8th character designator) in the D-
STAR protocol is unique enough for endpoint determination.
The routing is pretty simple in my "simple" mind.
Gateway receives a D-STAR header.
If it knows the destination (URCALL) already (say its on a locally
attached repeater or at a cached gateway location), it sends it to the
destination.
If it doesn't know the destination it asks the "trust server" where
to deliver it (probably the IP of the gateway to last report seeing
the callsign)
If it can't find the destination, it sends a service message back to
the origin callsign that the destination callsign is unknown.
The gateway also looks at the source (MYCALL)
If it is already cached as being on an attached repeater, do
nothing
If it is from an attached repeater and either doesn't exist or is
marked being on another gateway, update the trust that the callsign is
now on this gateway
If it is from a remote gateway, update local cache to associate the
callsign with the remote gateway
Of course there is more code to it than that, to handle routing
loops, timeouts, etc., but I think it pretty much handles
"connectionless" D-STAR traffic.
For DD, this means you can run any Ethernet encapsulated protocol
between endpoints, not just TCP/IP. You can also use the address
space that makes sense, e.g. 10.x.x.x, 44.x.x.x, 192.168.x.x,
172.x.x.x, or x.x.x.x in the IP world.
John
On Jul 24, 2009, at 1:40 PM, dlake02 wrote:
John
The whole use of the 10.X.X.X addresses seems like a real mess, but
in fact, it could be put to very good use.
The advantage is that every callsign has a unique address in the
system, down to a device level.
A very similar concept exist in the cellular networks - each device
has it's own identity and that identity moves between cellular zones
and networks. Whilst callsigns are useful, there is no good routing
protocol for callsigns - that is what G2 attempts and fails to do
today.
Now, host addresses actually are very useful things, and there is no
reason why these couldn't be used to provide a much more scalable G2
architecture that retained it's compatibility with the existing G2
network. Advertising the movement of a /32 address across a small IP
network such as the G2 network using an IETF standard routing
protocol would be very quick.
I'm not going to go into great detail on my thoughts - there are
correct forums for doing that, and that isn't here. However, for
those that are Cisco IOS literate think about this:
- Three routers, connected via your favourite IGRP (mine is OSPF).
- DNS with a lookup to G4ULF 10.1.1.1
- OSPF on both routers with "redistribute connected" configured
- Create a loopback on R1 for 10.1.1.1/32. From R3 ping "g4ulf"
- Delete the loopback on R1 and create on R2 for 10.1.1.1/32. From
R3 ping "g4ulf"
Now, pretend the routers are G2 gateways and the loopback is created
from the "Last Heard" table....
David - G4ULF
John Hays
Amateur Radio: K7VE
[email protected]
