Loop Control

Cross-mode, multi mode or analogue etc

Should not –
* Go to more than one Talk Group on FreeDMR Network via OpenBridge.
* Go to more than one Server on FreeDMR Network
Be bridged to each other and back to same Talk Group ( Loop )

As Server owners you need to make sure any and all cross-mode, multi mode or analogue etc you permit to your server is set-up correct.
This can be done by asking for a architecture diagram of the set-up they offer.

Cross-mode, multi mode or analogue etc owners. Also need to make sure they do not introduce a loop into the FreeDMR Network. If you do, this will result in your link being terminated until it is fixed.

First rule :-   “KNOW WHAT YOU ARE DOING”
Second rule :-   Just because you can, does not mean you should.

Switch = Cross-mode, multi mode or analogue etc

From Simon

People are viewing XLX the wrong way.  It’s not an XLX network, it’s a DMR network.

There is only one sensible way to use XLX when connected to DMR – a single isolated XLX from a server bridged to a Talk Group.  If a whole network of peered XLX sits behind it, there is too high a risk that you will interdependently create a loop.
If you need several XLX servers, they should connect to the DMR network as individual servers at different points, not peer together and connect to DMR.

XLX <-> TG = fine
TG <-> XLX <-> XLX <-> TG – not fine!
Server <-> TG <-> XLX <-> TG <-> Server – not fine!

Part 2

Be very, very, careful.

In general, we are going to need (unfortunately but stick with me) a gentlemen’s (women’s) agreement on this based on common sense. I call it the “one hop” rule.

We are primarily a DMR network.  When connecting other systems, you can do so if there is only one “hop”. I.E, it is directly connected to your FreeDMRr Server.  What we don’t want is further hops.  So, one XLX connected to a TG on FreeDMR is fine.  One XLX connected to a TG on FreeDMR and then peered with other XLX systems is not fine.

The reason for this is as the external network gets bigger, the probability that at some stage this network is linked back in to freedmr, accidentally or on purpose gets higher.  XLX is a particular problem here.

Again, we are building a DMR network, not a YSF, D-Star or multi-mode one….

Use the World Wide Talk Group List to see if a bridge has already been set-up.
If you do set-up a Bridge to a Talk Group.  Please let us know, so the list can be updated.

For Bridging to United Kingdom Talk Groups. Please read this.

* IF you MUST have a Talk Group go to a Talk Group that is already in use with a Bridge.
Set your Talk Group as Local only and not have it go out on the OPB.
This will stop Looping.
BUT still better to just use the original Talk group. Rather than making your own.