A large enterprise campus decided its conference rooms did not need an integrator.
The reasoning was fair. Facilities had put a UC bar in one room, it did not work at first, IT changed something on the network, and after that it worked most of the time.
Management saw a working room and approved more than 60 more like it. Facilities bought the bars and hung them. The physical install is easy. My team had built this customer's complex rooms years earlier, and nobody thought the simple ones needed us. Four little letters derailed the planned cost savings, mDNS.
Nothing would pair. No amount of reboots, replacing cables or updating firmware fixed it. The bars and the touch panels both powered up and pulled IP addresses. The panels still could not find the bars.
The floor pockets that fed the touch panels ran back to the enterprise switches, the ones provisioned for laptops. The bars on the walls ran to the AV switches. The two switch groups routed to each other fine, so on paper every device could reach every other device. But a touch panel finds its bar over mDNS, and mDNS is link-local by design. It rides multicast on UDP 5353 to a reserved link-local group and does not cross a routed boundary. Put the panel and the bar in different VLANs and the panel never sees the bar advertise itself.
The segmentation was correct. Laptops belong on the data network and AV endpoints belong on the AV network. That decision broke the one thing these particular devices needed, which was to share a broadcast domain long enough to find each other. That is a design question, and no one had been assigned to answer it.
So the simple rooms became a network project. The quick fix, moving the floor pocket ports onto the AV VLAN, was not available. The AV VLAN was not allowed on the enterprise switches, so every touch panel needed a new drop back to the AV switches. We spent real hours with the customer's IT team deciding where discovery was allowed to live. The fix is never exotic. Same VLAN, or an mDNS gateway like Cisco's Service Discovery Gateway or Aruba's AirGroup. Both are decisions someone makes on purpose.
A UC bar is a network appliance. The requirement that makes one discoverable does not ship in the box.
The customer still calls them the simple rooms.