Speed Interface Configuration

Use the speed interface configuration command to specify the speed of a 10/100 Mb/s or 10/100/1000 Mb/s port. Use the no or default form of this command to return the port to its default value.

You cannot configure speed on the 10-Gigabit Ethernet ports. Except for the 1000BASE-T SFP modules, if an SFP module port is connected to a device that does not support autonegotiation, you can configure the speed to not negotiate (nonegotiate). If the speed is set to auto, the switch negotiates with the device at the other end of the link for the speed setting and then forces the speed setting to the negotiated value. The duplex setting remains as configured on each end of the link, which could result in a duplex setting mismatch. If both ends of the line support autonegotiation, we highly recommend the default autonegotiationsettings. If one interface supports autonegotiation and the other end does not, do use the auto setting on the supported side, but set the duplex and speed on the other side.

Caution: Changing the interface speed and duplex mode configuration might shut down and re-enable the interface during the reconfiguration.

Example

This example shows how to set the speed on a port to 100 Mb/s:

Switch(config)# interface gigabitethernet1/0/1

Switch(config-if)# speed 100

This example shows how to set a port to autonegotiate at only 10 Mb/s:

Switch(config)# interface gigabitethernet1/0/1

Switch(config-if)# speed auto 10

This example shows how to set a port to autonegotiate at only 10 or 100 Mb/s:

Switch(config)# interface gigabitethernet1/0/1

Switch(config-if)# speed auto 10 100

You can verify your settings by entering the show interfaces privileged EXEC command.

srr-queue bandwidth limit

Use the srr-queue bandwidth limit interface configuration command to limit the maximum output on a port. Use the no form of this command to return to the default setting.

srr-queue bandwidth limit weight1

no srr-queue bandwidth limit

Usage Guidelines

If you configure this command to 80 percent, the port is idle 20 percent of the time. The line rate drops to 80 percent of the connected speed. These values are not exact because the hardware adjusts the line rate in increments of six. This command is not available on a 10-Gigabit Ethernet interface.

Note: The egress queue default settings are suitable for most situations. You should change them only when you have a thorough understanding of the egress queues and if these settings do not meet your quality of service (QoS) solution.

Example

This example shows how to limit a port to 800 Mb/s:

Switch(config)# interface gigabitethernet2/0/1

Switch(config-if)# srr-queue bandwidth limit 80

You can verify your settings by entering the show mls qos interface [interface-id] queueing privileged EXEC command.