Managing HP Serviceguard for Linux, Sixth Edition, August 2006

Understanding Serviceguard Software Components
How the Network Manager Works
Chapter 370
Bonding of LAN Interfaces
On the local node, several LAN interfaces can be grouped together in a
process known in Linux as channel bonding. In the bonded group, one
interface is used to transmit and receive data, while the others are
available as backups. If one interface fails, another interface in the
bonded group takes over. It is strongly recommended to use channel
bonding in each critical IP subnet to achieve highly available network
services.
Although Host Bus Adapters (HBAs) do not have to be identical, bonding
is supported only between Ethernet LANs of the same type.
Serviceguard for Linux supports the use of bonding of LAN interfaces at
the driver level. The Ethernet driver is configured to employ a group of
interfaces.
Once bonding is enabled, each interface can be viewed as a single logical
link of multiple physical ports with only one IP and MAC address. There
is no limit to the number of slaves (ports) per bond, and the number of
bonds per system is limited to the number of Linux modules you can
load.
You can bond the ports within a multi-ported networking card (cards
with up to four ports are currently available). Alternatively, you can bond
ports from different cards. Figure 3-17 shows an example of four
separate interfaces bonded into one aggregate.
Figure 3-17 Bonded Network Interfaces
Both the Single and Dual ported LANs in the non-bonded configuration
have four LAN cards, each associated with a separate non-aggregated IP
address and MAC address, and each with its own LAN name (eth1, eth2,
eth3, eth4). When these ports are aggregated, all four ports are