Cisco ASA Series Cli Configuration Manual page 409

Chapter 1 Starting Interface Configuration (ASA 5510 and Higher)
Redundant Interfaces
A logical redundant interface consists of a pair of physical interfaces: an active and a standby interface.
When the active interface fails, the standby interface becomes active and starts passing traffic. You can
configure a redundant interface to increase the ASA reliability. This feature is separate from device-level
failover, but you can configure redundant interfaces as well as device-level failover if desired.
Redundant Interface MAC Address
The redundant interface uses the MAC address of the first physical interface that you add. If you change
the order of the member interfaces in the configuration, then the MAC address changes to match the
MAC address of the interface that is now listed first. Alternatively, you can assign a MAC address to the
redundant interface, which is used regardless of the member interface MAC addresses (see the
"Configuring the MAC Address and MTU" section on page 1-10
section on page
maintained so that traffic is not disrupted.
EtherChannels
An 802.3ad EtherChannel is a logical interface (called a port-channel interface) consisting of a bundle
of individual Ethernet links (a channel group) so that you increase the bandwidth for a single network.
A port channel interface is used in the same way as a physical interface when you configure
interface-related features.
You can configure up to 48 EtherChannels.
This section includes the following topics:
•
•
•
•
•
Channel Group Interfaces
Each channel group can have eight active interfaces. Note that you can assign up to 16 interfaces to a
channel group. While only eight interfaces can be active, the remaining interfaces can act as standby
links in case of interface failure.
All interfaces in the channel group must be the same type and speed. The first interface added to the
channel group determines the correct type and speed.
The EtherChannel aggregates the traffic across all the available active interfaces in the channel. The port
is selected using a proprietary hash algorithm, based on source or destination MAC addresses, IP
addresses, TCP and UDP port numbers and vlan numbers.
Connecting to an EtherChannel on Another Device
The device to which you connect the ASA EtherChannel must also support 802.3ad EtherChannels; for
example, you can connect to the Catalyst 6500 switch.
1-15). When the active interface fails over to the standby, the same MAC address is
Channel Group Interfaces, page 1-5
Connecting to an EtherChannel on Another Device, page 1-5
Link Aggregation Control Protocol, page 1-6
Load Balancing, page 1-7
EtherChannel MAC Address, page 1-8
Information About Starting ASA 5510 and Higher Interface Configuration
Cisco ASA Series CLI Configuration Guide
or the "Configuring Multiple Contexts"
1-5