The switch is managed at the management console, which is either a 10/100/1000 Ethernet connection at the NET MGT port or a serial device attached to the SER MGT port.
The NET MGT connection is the default means of communicating with the SP. The SP has a DHCP client in operation and requires the Ethernet network to have a DHCP server. The DHCP server must be configured with the MAC address of the SP, so the server can provide an IP address to the SP upon booting. If a DHCP server is not available, then the SER MGT connection is used.
The advantage of the NET MGT connection over the SER MGT connection is that administration of the gateway can happen from anywhere on the network. There is no cable length constraint for the network management route because of the re-amplification, filtering, and processing that happens at each hub or switch within the Ethernet network. No network management cable should be any longer than 100 meters.
The SER MGT connection requires a serial connection to a serial device management console. The serial device management console can be a serial terminal, a terminal server, or a serial connection running on a system or laptop.
If no DHCP server is available on the management network, the SER MGT port must be used to configure the NET MGT port. Because of the nature of the serial signal, a serial management cable cannot be used reliably if it is more than 10 meters long.