Managing Serviceguard Fifteenth Edition, reprinted May 2008

Understanding Serviceguard Software Components
How the Network Manager Works
Chapter 3 99
How the Network Manager Works
The purpose of the network manager is to detect and recover from
network card failures so that network services remain highly available to
clients. In practice, this means assigning IP addresses for each package
to the primary LAN interface card on the node where the package is
running and monitoring the health of all interfaces, switching them
when necessary.
NOTE Serviceguard monitors the health of the network interfaces (NICs) but
does not perform network connectivity checking.
Stationary and Relocatable IP Addresses
Each node (host system) should have at least one IP address for each
active network interface. This address, known as a stationary IP
address, is configured in the node's /etc/rc.config.d/netconf file or
in the node’s /etc/rc.config.d/netconf-ipv6 file. A stationary IP
address is not transferable to another node, but may be transferable to a
standby LAN interface card. The stationary IP address is not associated
with packages. Stationary IP addresses are used to transmit heartbeat
messages (described earlier in the section “How the Cluster Manager
Works”) and other data.
IMPORTANT Every subnet configured as a monitored_subnet in a package
configuration file must be configured as a STATIONARY_IP in the cluster
configuration file. See “Cluster Configuration Parameters” on page 156
and “Package Parameter Explanations” on page 287 for more
information.
In addition to the stationary IP address, you normally assign one or more
unique IP addresses to each failover package. The package IP address is
assigned to the primary LAN interface card by the cmmodnet command
in the package control script when the package starts up.