Application BLF update notifications are broadcasted on to the same subnet as the IP Office. In the case of IP Office Control Units that have two local subnets , the messages are broadcasted to both subnets.

The only limitations of broadcast message BLF updates is the size of the subnet. A 24 bit Class C subnet allows up to 254 host IP addresses. One of those will be the IP Office, so there is the potential to have up to 253 other computerou s on that network.