DMR Re-Engineering

The DMR community is in the process of re-engineering a number of talk groups on the DMR system.  Here’s some background on what happened.

I plan to write a more technical article on how DMR talk group routing works.  For our purposes, all you really need to know is that every talk group has a “host.”  That host is either a cBridge or BrandMeister.  Any cBridge that wishes to carry a particular talk group for the repeaters it services should feed that talk group from the “host.”  In the case of the Ohio Statewide talk group, 3139, the host is currently DMRX.

On last week’s Ohio statewide net (Wednesday evening on 3139), I observed a significant delay on our Warrensville Heights and Thompson repeaters.  I would hear the traffic on my hotspot and other repeaters, and then our repeaters 30 or more seconds later.  It essentially made it impossible for users of our repeaters to participate in the net.

Unfortunately, at the time, I was unable to fully troubleshoot the issue.  After troubleshooting the network connections at the repeaters and our cBridge, I then thought that there could be some issue on the DMRX side of things, but I had no evidence to support that theory.  I was stumped.  I sent a request for technical support to a mailing list set up for administrators of cBridges that feed talk groups from DMRX.  I received good suggestions on what to look at the next time this happens.

After a lengthy discussion on the mailing list, someone mentioned that DMRX may be overloaded.  It was decided that the talk groups that DMRX currently hosts would be redistributed to other cBridges.  This would lighten the load on any one cBridge and allow for more decentralization on the DMR system.

We (the community of cBridge and BrandMeister administrators) are now in the process of determining where each of DMRX’s talk groups will be hosted going forward, and reconfiguring our bridge connections to reflect that.  It’s a tedious process, but I think in the end we will have a more distributed and robust network.

I am trying my best to help organize this effort, especially within the state of Ohio.  I’ve been in contact with a number cBridge and repeater owners all over the state, trying to ensure that the transition – at least for Ohio Statewide 3139 – goes smoothly.  I am also maintaining the master list of soon-to-be former DMRX-hosted talk groups and where they’re going to end up. This affects a total of 29 talkgroups, including several state-wide talk groups and TAC312-319.

If you are an end user or repeater owner, you won’t have to do anything.  The only impact this might have on you is short periods of time where certain talk groups are unavailable or don’t work correctly.

Check my website regularly for updates.

If I missed anything, or if you have any questions about this, please comment below.

Edit, April 23, 10:35PM: I incorrectly used the term “shutting down operations” in reference to DMRX – removed that.

Edit, April 24, 7:45PM: Removed unnecessary details and added information for end users.