38 IBM Certification Study Guide AIX HACMP
SLIP are considered public networks. Note that a SLIP line, however,
does not provide client access.
Private A private network provides communication between nodes only; it
typically does not allow client access. An SOCC line or an ATM
network are also private networks; however, an ATM network does
allow client connections and may contain standby adapters. If an
SP node is used as a client, the SP Switch network, although
private, can allow client access.
Serial This network attribute is used for non TCP/IP networks (see 2.2.2,
“Non-TCPIP Networks” on page 14.)
2.4.3.3 Network Adapters
A network adapter (interface) connects a node to a network. A node typically
is configured with at least two network interfaces for each network to which it
connects: a service interface that handles cluster traffic, and one or more
standby interfaces. A service adapter must also have a boot address defined
for it if IP address takeover is enabled.
Adapters in an HACMP cluster have a label and a function (service, standby,
or boot). The maximum number of network interfaces per node is 24.
Adapter Label
A network adapter is identified by an adapter label. For TCP/IP networks, the
adapter label
is the name in the /etc/hosts file associated with a specific IP
address. Thus, a single node can have several adapter labels and IP
addresses assigned to it. The adapter labels, however, should not be
confused with the “hostname”, of which there is only one per node.
Adapter Function
In the HACMP for AIX environment, each adapter has a specific function that
indicates the role it performs in the cluster. An adapter’s function can be
service, standby, or boot.
Service Adapter The service adapter is the primary connection between
the node and the network. A node has one service adapter
for each physical network to which it connects. The
service adapter is used for general TCP/IP traffic and is
the address the Cluster Information Program (Clinfo)
makes known to application programs that want to monitor
or use cluster services.
In configurations using rotating resources, the service
adapter on the standby node remains on its boot address