Managing Serviceguard Fifteenth Edition, reprinted May 2008

Understanding Serviceguard Software Components
How the Network Manager Works
Chapter 3100
The IP addresses associated with a package are called relocatable IP
addresses (also known as package IP addresses or floating IP
addresses) because the addresses can actually move from one cluster
node to another on the same subnet. You can use up to 200 relocatable IP
addresses in a cluster, spread over as many as 150 packages. This can be
a combination of IPv4 and IPv6 addresses.
Because system multi-node and multi-node packages do not fail over,
they do not have relocatable IP address.
A relocatable IP address is like a virtual host IP address that is assigned
to a package. HP recommends that you configure names for each package
through DNS (Domain Name Service). A program can then use the
package’s name like a host name as the input to gethostbyname(),
which will return the package's relocatable IP address.
Both stationary and relocatable IP addresses will switch to a standby
LAN interface in the event of a LAN card failure.
In addition, relocatable addresses (but not stationary addresses) can be
taken over by an adoptive node on the same subnet if control of the
package is transferred. This means that applications can access the
package via its relocatable address without knowing which node the
package currently resides on.
NOTE It is possible to configure a cluster that spans subnets joined by a router,
with some nodes using one subnet and some another. This is called a
cross-subnet configuration. In this context, you can configure packages
to fail over from a node on one subnet to a node on another, and you will
need to configure a relocatable address for each subnet the package is
configured to start on; see “About Cross-Subnet Failover” on page 191,
and in particular the subsection “Implications for Application
Deployment” on page 192.
Types of IP Addresses
Both IPv4 and IPv6 address types are supported in Serviceguard. IPv4
addresses are the traditional addresses of the form n.n.n.n where n is a
decimal digit between 0 and 255. IPv6 addresses have the form
x:x:x:x:x:x:x:x where x is the hexadecimal value of each of eight
16-bit pieces of the 128-bit address. Only IPv4 addresses are supported
as heartbeat addresses, but both IPv4 and IPv6 addresses (including