Managing Serviceguard Eighteenth Edition, September 2010

Local Primary/Standby LAN Patterns
The use of IPv6 allows a number of different patterns of failover among LAN cards
configured in the cluster. This is true because each LAN card can support several IP
addresses when a dual IPv4/IPv6 configuration is used. This section describes several
ways in that local failover to a standby LAN can be configured.
By definition, a standby network interface is an interface that has no IP address(es) of
either address family (IPv4 or IPv6) and is bridged to the primary network interface
on a node.
Here are two guidelines to keep in mind when using IPv4 and IPv6 addresses in local
failover situations:
• Since a network interface card can have both an IPv4 and an IPv6 address as the
primary IPs, the standby network interface card could potentially act as a standby
for both types of primary interfaces.
However, if the IPv4 and IPv6 address(es) are configured on two separate network
interfaces, then the standby interface can take over the IP address from only one
network interface during a local failover.
That is, IPv4 and IPv6 addresses from two separate network interfaces are mutually
exclusive in a failover condition.
• Serviceguard will switch over link-local address configured on the primary network
interface along with all other IP addresses which are configured as part of the
cluster configuration to the standby network interface. This includes all heartbeat
and stationary IPs (IPv4 and IPv6) and package IPs (both IPv4 and IPv6) added
by Serviceguard.
The examples that follow illustrate this.
Example Configurations
An example of a LAN configuration on a cluster node using both IPv4 and IPv6
addresses is shown in below.
Local Primary/Standby LAN Patterns 481