When using IP-enabled physical security devices, the only way they can be useful is when they are connected to a local area network (LAN), which is the only method by which such devices can communicate. There are a number of issues involved when IP security devices are placed on a network, and astute security technicians must know how to manage network issues and troubleshoot common network problems as they relate to the security system components.
The first issue to consider is whether the network in question can be actively managed or not. Most home and small business networks utilize unmanaged switches, which typically have no monitoring or diagnostic capabilities. This limits the troubleshooting capabilities of the network, as the central switch(es) cannot report whether it has a problem or what the problem might be. So the only troubleshooting indications from the unmanaged switch are the “happy” LEDs that indicate whether a device is connected and communicating on a particular switch port.