Cisco Systems OL-16647-01 Redundant Interface Overview

7-2

Cisco ASDM User Guide

OL-16647-01

Chapter 7 Configuring Interfaces in Single Mode

Interface Overview

• Default Physical Interface Settings, page 7-2

• Connector Types, page 7-2

• Auto-MDI/MDIX Feature, page 7-2

By default, the speed and duplex for copper (RJ-45) interfaces are set to auto-negotiate.

The ASA 5550 adaptive security appliance and the 4GE SSM for the ASA 5510 and higher adaptive

security appliance include two connector types: copper RJ-45 and fiber SFP. RJ-45 is the default.

To use the fiber SFP connectors, you must set the media type to SFP. The fiber interface has a fixed speed

and does not support duplex, but you can set the interface to negotiate link parameters (the default) or

not to negotiate.

For RJ-45 interfaces on the ASA 5500 series adaptive security appliance, the default auto-negotiation

setting also includes the Auto-MDI/MDIX feature. Auto-MDI/MDIX eliminates the need for crossover

cabling by performing an internal crossover when a straight cable is detected during the auto-negotiation

phase. Either the speed or duplex must be set to auto-negotiate to enable Auto-MDI/MDIX for the

interface. If you explicitly set both the speed and duplex to a fixed value, thus disabling auto-negotiation

for both settings, then Auto-MDI/MDIX is also disabled.

Redundant Interface Overview

A logical redundant interface pairs an active and a standby physical interface. When the active interface

fails, the standby interface becomes active and starts passing traffic. You can configure a redundant

interface to increase the security appliance reliability. This feature is separate from device-level failover,

but you can configure redundant interfaces as well as failover if desired. You can configure up to 8

redundant interface pairs.

All subsequent security appliance configuration refers to the logical redundant interface instead of the

member physical interfaces.

This section includes overview information about redundant interfaces, and includes the following

topics:

• Redundant Interfaces and Failover Guidelines, page 7-2

• Redundant Interface MAC Address, page 7-3

• Physical Interface Guidelines for Use in a Redundant Interface, page 7-3

Follow these guidelines when adding member interfaces:

• If you want to use a redundant interface for the failover or state link, then you must configure the

redundant interface as part of the basic configuration on the secondary unit in addition to the primary

unit.