On 1/21/2010 10:34 AM, Woodrick, Ed wrote:
Actually the way that routi ng is done in D-STAR is much better than the routing done in the basic AX.25 protocol. In AX.25, you had to specify each node along a path. The additional protocol stacks like KA-Node and others act a little more like D-STAR routing in that once connected to the network, you then specify the destination and the network automatically figures out how to get there.
Not to go TOO far afield from D-STAR here, but AX.25 networks could have EASILY added what D-STAR has... a master DB that did a lookup on a destination and just "went there" with the datagrams.
The real killer of AX.25 for anything except APRS was bandwidth. 1200 bps just isn't even CLOSE to useful these days, and my fear is that after the "newness" wears off, it won't be enough for D-STAR either.
It's really a shame that the D-STAR specification didn't include a flag to flip that says, "I'm using the ENTIRE available bandwidth of this stream for data, instead of making the same mistake early cell phone tech did, channelizing/timeslotting everything so there's "voice bandwidth" and "data bandwidth" and never the two shall mix.
9600 bps is far more useful, but still woefully inadequate for today's mobile data needs. The ID-1 at 128 kbs is BARELY adequate. Neither can come close to backing up the need for more bandwidth during a large-scale public network outage. They'll get the bare minimum number of emergency messages through in times of DIRE need, but I have a feeling they're "too little, too late" to make Amateur Radio seem "useful" in the modern world.
Mix that with other bigger picture items like our inability to encrypt easily (a modern network REQUIREMENT, not a "nice to have" feature anymore) under the laws in most countries where Amateur Radio is popular, and other things (the recent hullaballoo over Amateurs who work in Public Safety not doing Amateur Radio things while on the job, for example) makes us very unpalatable to many groups/agencies who otherwise would appreciate our services.
I've been saying this for years... we're the guys that show up and get Comm going for the first 72 hours. After that, the larger and better funded organizations will be 95%+ back online or the areas affected will be evacuated. We're far more useful to emergency folks if we show up with a $500 satellite uplink, knowledge of how to provision a NAT router and 802.11 -- than we are as Amateur operators. We LEARN the RF basics and electronics basics to handle "let's slap something together that works", but showing up saying "this D-STAR radio will fix your problems", just ain't gonna cut it, these days. It'll fix their problem in a poor way until the cellular company COW trucks roll in. That's about it.
I'm not saying this is "good" or "bad" in any way, just pointing out the realistic facts about our Amateur Radio technology. An emergency communications vehicle should have a D-STAR rig, but it's about 10th down the priority list behind a generator, a satellite uplink, a sat phone, and a bunch of other things.
ARRL's marketing campaign that seems to indicate our TECHNOLOGY is the answer for Emergency Services, is misguided. Our KNOW-HOW is far more important. Problem is, our testing and licensing is based on RF principals and Safety, and leaves out the most important things we have to offer the world... our knowledge of how to get the networks, computers, and other things up and running...
Sorry if this is too far off-topic. I'd bring it up at a dinner party with D-STAR fans, so I bring it up here. We must be realistic about where we add value or don't add value.
Nate WY0X
