Troubleshooting guide

1-3
Cisco Wide Area Application Services Configuration Guide
OL-26579-01
Chapter 1 Configuring Network Settings
Configuring Network Interfaces
Configuring a Standby Interface
In this procedure, you configure a logical interface called a standby interface. After you configure this
standby interface, you must associate physical or port-channel interfaces with the standby interface to
create the standby group. In the WAAS Central Manager, you create the standby group by assigning two
interfaces to the standby group and assigning one as primary.
Standby interfaces remain unused unless a member interface that is in use fails. When an in-use network
interface fails (because of cable trouble, Layer 2 switch failure, or other failure), the other member
interface of the standby group changes its state to in use and starts to carry traffic and take the load off
the failed interface. With the standby interface configuration, only one interface is in use at a given time.
To configure standby interfaces, you must assign two physical or two port-channel interface members to
a standby group. The following operating considerations apply to standby groups:
• A standby group consists of two physical or two port-channel interfaces. (If you are configuring a
WAAS device running a version earlier than 5.0, both interfaces must be physical interfaces.)
• The maximum number of standby groups on a WAAS device is two. When using a Cisco AppNav
Controller Interface Module, you can have up to three standby groups.
• A standby group is assigned a unique standby IP address, shared by all members of the group.
• Configuring the duplex and speed settings of the standby group member interfaces provides better
reliability.
• IP ACLs can be configured on physical interfaces that are members of a standby group.
• One interface in a standby group is designated as the primary standby interface. Only the primary
interface uses the group IP address.
• If the in-use interface fails, another interface in its standby group takes over and carries the traffic.
• If all the members of a standby group fail, then one recovers, the WAAS software brings up the
standby group on the operational interface.
• The primary interface in a standby group can be changed at runtime. (The default action is to
preempt the currently in-use interface if a different interface is made primary.)
• If a physical interface is a member of a standby group, it cannot also be a member of a port channel.
• If a device has only two interfaces, you cannot assign an IP address to both a standby group and a
port channel. On such a device, only one logical interface can be configured with an IP address.
• The member interfaces of a standby group can be connected to different switches if you use a VLAN
tagging protocol and assign the same VLAN tag to each interface.
• You cannot include a built-in Ethernet port and a port on a Cisco Interface Module in the same
standby group.
Configuring a standby interface differs, depending on the version of the WAAS device that you are
configuring. See one of the following topics:
• Configuring a Standby Interface on a Device with Version 5.0 or Later, page 1-4
• Configuring a Standby Interface on a Device Earlier than Version 5.0, page 1-5