KS-DMR Network Backend

KS-DMR uses a number of inter-operable building blocks. The diagrams here show the logical layouts for the repeaters and the software used to link them to each other; our “upstream” feeds, and the physical and logical back-end server and IP network infrastructure that facilitates it.

Other than a legacy c-Bridge which is used as a protocol translator for our DMR-MARC feeds, KS-DMR is built entirely on our own software. We use call-routing packages from DMRlink (Motorola IPSC networking) and HBlink (home-brew repeater protocol and OpenBridge networking) as the main building blocks of the network, with the IPSC<->HBP protocol translation modules in DMRlink and HBlink as our “bridge” between the two different protocols.

This is the “engine” of KS-DMR, a Dell PowerEdge R610 that hosts the software and processes that are depicted in the backend diagram below.

In the fall of 2018, we decided to bring our infrastructure in-house and stop using low-cost cloud servers (Digital Ocean, Atlantic, low-end AWS, etc.). Since that time we’ve had considerably increased reliability. The current physical server infrastructure is located in Kansas, and is fully virtualized to create a modular environment where different aspects of our system are contained in their own, isolated virtual machines. Our server equipment is co-located at the Kansas Research and Education Network (KanREN, Inc) free of charge. It is connected directly to the KanREN 100Gbps core backbone network.

Our entire network is built on publicly routable IP space, including L2TP over IPSEC VPN connections for our repeaters. This eliminates problems with NAT, port-forwarding, etc., and as such, requires no “router rebooting” to keep the network functional. Repeaters where VPN is prohibited or unnecessary may still connect in a traditional fashion.