At 07:50 AM 9/5/2009, you wrote:
>Hi John, > >While I appreciate you taking the time and trouble to answer my >question, It's WAY too much info for me to digest. What the question >probably should have been it this: > >If I connect to a local D-Star repeater and have WD7STRCL in UR and >another station via another D-Star has already linked to WD7STR, >will I be able to link? If so, how many repeaters can link? You're still thinking in terms of linking. With D-STAR, you really have to go back to first base and start all over again. D-STAR also has multiple modes of passing traffic between stations, which can be broadly divided into 2 categories, namely "Traditional/G2 based" and "DPlus additions". The traditional and G2 modes are what John described in his reply to you. These do not use links of such, they are one way routes that you configure into your radio. The party at the other end has to configure a reciprocal route back to you, for you to be able to communicate. Fortunately, the Icom radios have a "1 touch reply" function which makes this easy to achieve. I'll ignore the non networked cases for now, and look at traditional routing options. 1. Callsign routing. This is used to route to a user who could be anywhere on the D-STAR network. You don't need to know where they are, and the D-STAR network will route to them. For example, to call you, I could do this... MY = VK3JED UR = WB4WTN R1 = VK3RWN C R2 = VK3RWN G R1 is my local RF port, R2 is my local gateway. UR is where I am routing to, in this case, your callsign Bill. If D-STAR knows about you and has heard you on, the call will be routed to where you were last heard on air. This is a _very_ useful feature of callsign routing. 2. Port routing. Similar to callsign routing, except you're specifying the RF port that you will be coming out on, rather than the destination callsign. For example, if I wanted to route to W1ABC port B, I would use... MY = VK3JED UR = /W1ABC B R1 = VK3RWN C R2 = VK3RWN G Note the slash at the start of the UR entry. The port designator always occupies the 8th character position. Due to the nature of the above callsign routing, it's not easy to have more than routing to one place at the same time, so bandwidth so far is minimal. 3. Multicast. This broadcasts your call to the list of gateways setup by your local gateway admin for that multicast group. To use a multicast group, first, the gateway admins involved must configure it beforehand. Once that is done, simple MY = VK3JED UR = /OURNET R1 = VK3RWN C R2 = VK3RWN G Of these, multicast is the one that takes the bandwidth at the gateway, since it has to send a copy of each local user's transmission to all other group member gateways. There is a hard limit of 10 gateways in a multicast group, so the Internet connection needs to be able to handle 9x DV streams (plus DV from any other ports and any DD traffic) at the same time. Next, we move onto the DPlus enhancements. These are NOT part of a standard G2 D-STAR setup, but are provided by the DPlus addon by Robin, AA4RC, which most gateways on the K5TIT network run today. DPlus has its own way of working, and here we can talk about links in a manner similar to IRLP and Echolink. When a DPlus link is established, all traffic (all that has the gateway in the G2 field anyway) is sent to the copy of DPlus running on the remote end. No need to have callsign routing configured (actually, you shouldn't, that can screw up the system when a DPlus link is active). I won't go into the details of how to setup and tear down DPlus links, but the limits on how many can connect would depend on bandwidth at the gateway, just as is the case for Echolink. Like Echolink and IRLP, large nets can be held using DPlus, thanks to the presence of reflectors, which are simply conference servers on high bandwidth pipes. As you can see, the question has many answers. :) 73 de VK3JED / VK3IRL http://vkradio.com
