IPMP Interface Configurations
An IPMP configuration typically consists of two or more physical interfaces on
the same system that are attached to the same IP link. These physical
interfaces might or might not be on the same NIC. The interfaces are
configured as members of the same IPMP group. If the
system has additional interfaces on a second IP link, you must configure
these interfaces as another IPMP group.
A single interface can be configured in its own IPMP group. The
single interface IPMP group has the same behavior as an IPMP group with
multiple interfaces. However, failover and failback cannot occur for an IPMP group with
only one interface.
Standby Interfaces in an IPMP Group
The standby interface in an IPMP group is not used for data traffic unless
some other interface in the group fails. When a failure occurs, the data
addresses on the failed interface migrate to the standby interface. Then, the standby
interface is treated the same as other active interfaces until the failed interface
is repaired. Some failovers might not choose a standby interface. Instead, these failovers
might choose an active interface with fewer data addresses that are configured as
UP than the standby interface.
You should configure only test addresses on a standby interface. IPMP does not
permit you to add a data address to an interface that is
configured through the ifconfig command as standby. Any attempt to create this type of
configuration will fail. Similarly, if you configure as standby an interface that already has
data addresses, these addresses automatically fail over to another interface in the IPMP
group. Due to these restrictions, you must use the ifconfig command
to mark any test addresses as deprecated and -failover prior to setting
the interface as standby. To configure standby interfaces, refer to How to Configure a Standby Interface for an IPMP Group.
Common IPMP Interface Configurations
As mentioned in IPMP Addressing, interfaces in an IPMP group handle regular data traffic
and probe traffic, depending on the interfaces' configuration. You use IPMP options of
the ifconfig command to create the configuration.
An active interface is a physical interface that transmits both data traffic and probe
traffic. You configure the interface as “active” by performing either the task How to Configure an IPMP Group With Multiple Interfaces
or the task How to Configure a Single Interface IPMP Group.
The following are two common types of IPMP configurations:
- Active-active configuration
A two interface IPMP group where both interfaces are “active,” that is they might be transmitting both probe and data traffic at all times.
- Active-standby configuration
A two interface IPMP group where one interface is configured as “standby.”
Checking the Status of an Interface
You can check the status of an interface by issuing the ifconfig
interface command. For general information on ifconfig status reporting, refer to How to Get Information About a Specific Interface.
For example, you can use the ifconfig command to obtain the status of
a standby interface. When the standby interface is not hosting any data address,
the interface has the INACTIVE flag for its status. You can observe this
flag in the status lines for the interface in the ifconfig output.