Dell PowerSwitch S4820T 9.50.1 Configuration Guide for the S4820T System - Page 444

The local interface and the directly connected remote interface must have the same setting, and autonegotiation is the easiest way to accomplish that, as long as the remote interface is capable of autonegotiation. NOTE: As a best practice, Dell Networking recommends keeping auto-negotiation enabled. Only disable auto-negotiation on switch ports that attach to devices not capable of supporting negotiation or where connectivity issues arise from interoperability issues. For 10/100/1000 Ethernet interfaces, the negotiation auto command is tied to the speed command. Auto-negotiation is always enabled when the speed command is set to 1000 or auto. Setting the Speed and Duplex Mode of Ethernet Interfaces To discover whether the remote and local interface requires manual speed synchronization, and to manually synchronize them if necessary, use the following command sequence. 1. Determine the local interface status. Refer to the following example. EXEC Privilege mode show interfaces [interface | linecard slot-number] status 2. Determine the remote interface status. EXEC mode or EXEC Privilege mode [Use the command on the remote system that is equivalent to the first command.] 3. Access CONFIGURATION mode. EXEC Privilege mode config 4. Access the port. CONFIGURATION mode interface interface slot/port 5. Set the local port speed. INTERFACE mode speed {10 | 100 | 1000 | auto} 6. Optionally, set full- or half-duplex. INTERFACE mode duplex {half | full} 7. Disable auto-negotiation on the port. INTERFACE mode no negotiation auto If the speed was set to 1000, do not disable auto-negotiation. 8. Verify configuration changes. INTERFACE mode show config 444 Interfaces