Cisco Systems OL-4580-01 manual Configuring Interface Duplex and Speed

Chapter 1 Configuring Interfaces and Circuits

Configuring Interfaces

To remove an interface description, enter:

(config-if[2/1])# no description

Configuring Interface Duplex and Speed

By default, the CSS Fast Ethernet interface and Gigabit Ethernet interface are configured to auto-negotiate. The CSS automatically detects the network line speed (Fast Ethernet only) and duplex of incoming signals, and synchronizes those parameters during data transfer. Auto-negotiation enables the CSS and the other devices on the link to achieve the maximum common level of operation.

When using Fast Ethernet ports with older equipment that cannot transmit the duplex and speed with the signals, you can manually configure the speed

(10 Mbps, 100 Mbps) and duplex (half or full duplex) of the CSS port to match the transmitting equipment.

When you use Gigabit Ethernet ports, if the link does not come up (perhaps due to traffic congestion), you may need to force the CSS and its link partner in to a specific mode. The CSS allows you to manually select a full duplex and flow control (pause frame) mode. Flow control allows the CSS to control traffic during congestion by notifying the other port to stop transmitting until the congestion clears. When the other device receives the pause frame, it temporarily stops transmitting data packets. When the CSS detects local congestion and becomes overwhelmed with data, the Gigabit Ethernet ports transmits a pause frame. Both the CSS Gigabit Ethernet and its link partner must be configured with the same pause method (asymmetric, symmetric, or both). By default, all Gigabit Ethernet ports are configured to full duplex mode with symmetric pause (pause frames transmitted and received by the CSS).

Note If you configure the redundancy-phycommand on an interface of the master CSS in a box-to-box redundancy configuration and then make a change to the port settings of that interface using the phy command (for example, changing auto-negotiateto 100Mbits-FD), the master CSS fails over to the backup CSS. To prevent the failover from occurring, first enter the no redundancy-phycommand on the interface, change the port settings, and then reenter the redundancy-phycommand. For information about the redundancy-phycommand, refer to the Cisco Content Services Switch Redundancy Guide.

	Cisco Content Services Switch Routing and Bridging Configuration Guide
1-8	OL-4580-01