Chapter 11 Configuring Interface Characteristics

Configuring Ethernet Interfaces

 

Command

Purpose

Step 5

 

 

show interfaces interface-id

Verify the interface flow control settings.

Step 6

 

 

copy running-config startup-config

(Optional) Save your entries in the configuration file.

 

 

 

To disable flow control, use the flowcontrol receive off interface configuration command.

This example shows how to turn on flow control on a port:

Switch# configure terminal

Switch(config)# interface gigabitethernet1/0/1

Switch(config-if)#flowcontrol receive on

Switch(config-if)# end

Configuring Auto-MDIX on an Interface

When automatic medium-dependent interface crossover (auto-MDIX) is enabled on an interface, the interface automatically detects the required cable connection type (straight through or crossover) and configures the connection appropriately. When connecting switches without the auto-MDIX feature, you must use straight-through cables to connect to devices such as servers, workstations, or routers and crossover cables to connect to other switches or repeaters. With auto-MDIX enabled, you can use either type of cable to connect to other devices, and the interface automatically corrects for any incorrect cabling. For more information about cabling requirements, see the hardware installation guide.

Auto-MDIX is enabled by default. When you enable auto-MDIX, you must also set the interface speed and duplex to auto so that the feature operates correctly. Auto-MDIX is supported on all 10/100/1000-Mb/s and on 10/100/1000BASE-TX small form-factor pluggable (SFP)-module interfaces. It is not supported on 1000BASE-SX or -LX SFP module interfaces.

Table 11-4shows the link states that result from auto-MDIX settings and correct and incorrect cabling.

Table 11-4

Link Conditions and Auto-MDIX Settings

 

 

 

 

 

Local Side Auto-MDIX

Remote Side Auto-MDIX

With Correct Cabling

With Incorrect Cabling

 

 

 

 

 

On

 

On

Link up

Link up

 

 

 

 

 

On

 

Off

Link up

Link up

 

 

 

 

 

Off

 

On

Link up

Link up

 

 

 

 

 

Off

 

Off

Link up

Link down

 

 

 

 

 

Beginning in privileged EXEC mode, follow these steps to configure auto-MDIX on an interface:

 

 

Command

Purpose

 

Step 1

 

 

 

configure terminal

Enter global configuration mode

 

Step 2

 

 

 

interface interface-id

Specify the physical interface to be configured, and enter interface

 

 

 

configuration mode.

 

Step 3

 

 

 

speed auto

Configure the interface to autonegotiate speed with the connected device.

 

Step 4

 

 

 

duplex auto

Configure the interface to autonegotiate duplex mode with the connected

 

 

 

device.

 

Step 5

 

 

 

mdix auto

Enable auto-MDIX on the interface.

 

 

 

 

 

 

 

 

 

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

 

 

 

 

 

 

 

 

 

 

 

 

 

OL-9775-02

 

 

11-25

 

 

 

 

 

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Cisco Systems 3750E manual Configuring Auto-MDIX on an Interface, Local Side Auto-MDIX, With Correct Cabling, 11-25