By default, the SMS management port interface is set to auto-negotiate. You can connect the SMS management port to a hub or a switch that can manage 10 mbps, 100 mbps, or a 1 Gbps connection.
In accordance with the IEEE P802.3ab 1000BASE-T standard, auto-negotiation is a requirement for using 1000BASE-T. In a departure from both 10BASE-T and 100BASE-TX, 1000BASE-T uses all four cable pairs (CAT-5e/6) for simultaneous transmission in both directions through the use of adaptive equalization.
On the SMS, when auto-negotiation is disabled, some port options are limited. For example, 1000 Mbps line speed is only available for copper ports when auto-negotiation is enabled. When auto-negotiation is disabled, the line speed can only be set to 100 Mbps or 10 Mbps.
