At 12:16 PM 5/18/2009, you wrote: >I was definitely thinking of multicast. But saying "it's not possible" >is incorrect. It *is* possible, with admin interaction and a multicast >group per-arranged. Saying it's not as EASY, is correct.
True, in the strictest sense, but in the sense that the majority of amateur communications is either not pre-arranged, or in the case of scheduled nets, the systems participating are not set in stone in advance, then it's "impossible" for common amateur scenarios. In amateur VoIP, I usually deal with the following scenarios: 1. Point to point. This is where callsign routing in D-STAR is at its best, and on D-STAR, this is the mode I generally use for point to point QSOs. Callsign routing is particularly useful, when you're not sure where the other station is located. Another advantage of callsign routing is that it is stateless, so you don't need to remember to tear the connection down at the end, because there wasn't one. Just remove the UR callsign (in my setup, as easy as a flick of the VFO knob), when you're done. I setup my radio that the memory has no UR callsign, so I can't inadvertently route to a distant system. 2. Scheduled net, no fixed participation list, may be banned/muted systems. This covers nets such as the VoIP WX Net. The only net I have participated on D-STAR that is anything like this is the SE WX Net. IRLP and Echolink also allow for stations to be banned or muted. This is less of an issue on D-STAR, because most of those blocks are for technical issues that D-STAR doesn't have (repeater bounce, intermods, etc). DPlus is the only D-STAR game in town here. 3. Free form, multi-reflector networks. Some of the D-STAR reflectors probably come close to this, albeit on a single reflector. The archetype of this sort of operation is the VK/Ireland IRLP/Echolink network, which has at least two IRLP reflectors and 3 Echolink conferences participating. Occasionally, one or more of the connected systems is dropped off the network to segregate scheduled net traffic, usually by automated means (cron jobs, etc). Again, this is definitely NOT something that could be covered by multicast. The closest in the D-STAR world are those reflectors where general ragchewing is commonplace, and again, DPlus is the tool for the job. You can see why multicast doesn't do a lot for me. ;) So for 90% or more of possible scenarios, it's "not possible". For the other < 10%, you can use multicast. ;) And I ruled out multicast as a viable option, because I can't think of a net I participate in (on any mode, not just D-STAR), where all systems involved would be known in advance. 73 de VK3JED / VK3IRL http://vkradio.com
