If I understood it correctly, Zigbee Light Link (ZLL) networks function without a coordinator node (as opposed to Zigbee Home Automation networks where it is mandatory). Before I learned that I supposed that the 5-button remote control sold by IKEA plays the role of the coordinator for their Trådfri products because it is possible to control the bulbs directly with it without any other hardware. But since Trådfri is (or at least was) using ZLL, their should not be a coordinator at all. Given that assumption, I was wondering why it is still neccessary to bind a new bulb to a remote first before it can be controlled by the Trådfri gateway. Why is it not possible to just use a bulb and the gateway together without a remote control? Is that something vendor-specific that IKEA programmed into the bulbs' firmware? If so, is that a violation of the Zigbee standard or an allowed extension?