This read-only value reports which radio branch on this network element connects to the remote element's IP address, or zero if the remote address is not directly connected via radio. Admins use it to trace which physical radio link on the local network element provides connectivity to a given remote element, which matters when diagnosing a fault on a specific radio branch. For example, remoteElementRadioBranchId returning 2 tells the admin the remote element at that row's IP address is reached over radio branch 2 of this network element, while a value of 0 would mean it is not directly connected.