Managing HP Serviceguard A.11.20.10 for Linux, December 2012

Figure 23 Bonded NICs
Node1
Node2
bond0:
eth0
eth1
bond0:
eth0
eth1
active
active
Crossover cable
Hub
Hub
In the bonding model, individual Ethernet interfaces are slaves, and the bond is the master. In the
basic high availability configuration (mode 1), one slave in a bond assumes an active role, while
the others remain inactive until a failure is detected. (In Figure 3-18, both eth0 slave interfaces are
active.) It is important that during configuration, the active slave interfaces on all nodes are
connected to the same hub. If this were not the case, then normal operation of the LAN would
require the use of the crossover between the hubs and the crossover would become a single point
of failure.
After the failure of a card, messages are still carried on the bonded LAN and are received on the
other node, but now eth1 has become active in bond0 on node1. This situation is shown in
Figure 24.
Figure 24 Bonded NICs After Failure
Various combinations of Ethernet card types (single or dual-ported) and bond groups are possible,
but it is vitally important to remember that at least two physical cards (or physically separate
62 Understanding Serviceguard Software Components