System Administration Guide: IP Services

How to Configure an IPMP Group With Multiple Interfaces

The following steps for configuring an IPMP group also apply when configuring VLANs into an IPMP group.

Before You Begin

You need to have already configured the IPv4 addresses, and, if appropriate, the IPv6 addresses of all interfaces in the prospective IPMP group.

Caution –

You must configure only one IPMP group for each subnet or L2 broadcast domain. For more information, see Basic Requirements of IPMP

On the system with the interfaces to be configured, assume the Primary Administrator role, or become superuser.

The Primary Administrator role includes the Primary Administrator profile. To create the role and assign the role to a user, see Chapter 2, Working With the Solaris Management Console (Tasks), in System Administration Guide: Basic Administration.

Place each physical interface into an IPMP group.
# ifconfig interface group group-name
For example, to place hme0 and hme1 under group testgroup1, you would type the following commands:
# ifconfig hme0 group testgroup1 # ifconfig hme1 group testgroup1
Avoid using spaces in group names. The ifconfig status display does not show spaces. Consequently, do not create two similar group names where the only difference is that one name also contains a space. If one of the group names contains a space, these group names look the same in the status display.

In a dual-stack environment, placing the IPv4 instance of an interface under a particular group automatically places the IPv6 instance under the same group.

(Optional) Configure an IPv4 test address on one or more physical interfaces.

You need to configure a test address only if you want to use probe-based failure detection on a particular interface. Test addresses are configured as logical interfaces of the physical interface that you specify to the ifconfig command.

If one interface in the group is to become the standby interface, do not configure a test address for that interface at this time. You configure a test address for the standby interface as part of the task How to Configure a Standby Interface for an IPMP Group.

Use the following syntax of the ifconfig command for configuring a test address:
# ifconfig interface addif ip-address parameters -failover deprecated up
For example, you would create the following test address for the primary network interface hme0:
# ifconfig hme0 addif 192.168.85.21 netmask + broadcast + -failover deprecated up
This command sets the following parameters for the primary network interface hme0:
- Address set to 192.168.85.21
- Netmask and broadcast address set to the default value
- -failover and deprecated options set
  
  Note –
  You must mark an IPv4 test address as deprecated to prevent applications from using the test address.

Check the IPv4 configuration for a specific interface.

You can always view the current status of an interface by typing ifconfig interface. For more information on viewing an interface's status, refer to How to Get Information About a Specific Interface.

You can get information about test address configuration for a physical interface by specifying the logical interface that is assigned to the test address.
# ifconfig hme0:1 hme0:1: flags=9000843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER> mtu 1500 index 2 inet 192.168.85.21 netmask ffffff00 broadcast 192.168.85.255

(Optional) If applicable, configure an IPv6 test address.
# ifconfig interface inet6 -failover
Physical interfaces with IPv6 addresses are placed into the same IPMP group as the interfaces' IPv4 addresses. This happens when you configure the physical interface with IPv4 addresses into an IPMP group. If you first place physical interfaces with IPv6 addresses into an IPMP group, physical interfaces with IPv4 addresses are also implicitly placed in the same IPMP group.

For example, to configure hme0 with an IPv6 test address, you would type the following:
# ifconfig hme0 inet6 -failover
You do not need to mark an IPv6 test address as deprecated to prevent applications from using the test address.

Check the IPv6 configuration.

# ifconfig hme0 inet6
	hme0: flags=a000841<UP,RUNNING,MULTICAST,IPv6,NOFAILOVER> mtu 1500 index 2
        	inet6 fe80::a00:20ff:feb9:17fa/10 
        	groupname test

The IPv6 test address is the link-local address of the interface.

(Optional) Preserve the IPMP group configuration across reboots.
- For IPv4, add the following line to the /etc/hostname.interface file:
  interface-address <parameters> group group-name up \ addif logical-interface -failover deprecated <parameters> up
  In this instance, the test IPv4 address is configured only on the next reboot. If you want the configuration to be invoked in the current session, do steps 1, 2, and, optionally 3.
- For IPv6, add the following line to the /etc/hostname6.interface file:
  -failover group group-name up
  This test IPv6 address is configured only on the next reboot. If you want the configuration to be invoked in the current session, do steps 1, 2, and, optionally, 5.

(Optional) Add more interfaces to the IPMP group by repeating steps 1 through 6.

You can add new interfaces to an existing group on a live system. However, changes are lost across reboots.

Example 31–1 Configuring an IPMP Group With Two Interfaces

Suppose you want to do the following:

Have the netmask and broadcast address set to the default value.
Configure the interface with a test address 192.168.85.21.

You would type the following command:

# ifconfig hme0 addif 192.168.85.21 netmask + broadcast + -failover deprecated up

You must mark an IPv4 test address as deprecated to prevent applications from using the test address. See How to Configure an IPMP Group With Multiple Interfaces.

To turn on the failover attribute of the address, you would use the failover option without the dash

All test IP addresses in an IPMP group must use the same network prefix. The test IP addresses must belong to a single IP subnet.

Example 31–2 Preserving an IPv4 IPMP Group Configuration Across Reboots

Suppose you want to create an IPMP group called testgroup1 with the following configuration:

Physical interface hme0 with the data address 192.168.85.19
A logical interface with the test address 192.168.85.21

Note –
In this example, physical interface and data address are paired together. Likewise for logical interface and test address. However, no inherent relationships exist between an interface “type” and the address type.
deprecated and -failover options set
Netmask and broadcast address set to the default value

You would add the following line to the /etc/hostname.hme0 file:

192.168.85.19 netmask + broadcast + group testgroup1 up \
	addif 192.168.85.21 deprecated -failover netmask + broadcast + up

Similarly, to place the second interface hme1 under the same group testgroup1 and to configure a test address, you would add the following line:

192.168.85.20 netmask + broadcast + group testgroup1 up \
	addif 192.168.85.22 deprecated -failover netmask + broadcast + up

Example 31–3 Preserving an IPv6 IPMP Group Configuration Across Reboots

To create a test group for interface hme0 with an IPv6 address, you would add the following line to the /etc/hostname6.hme0 file:

-failover group testgroup1 up

Similarly, to place the second interface hme1 in group testgroup1 and to configure a test address, you would add the following line to the /etc/hostname6.hme1 file:

-failover group testgroup1 up

Troubleshooting

During IPMP group configuration, in.mpathd outputs a number of messages to the system console or to the syslog file. These messages are informational in nature and indicate that the IPMP configuration functions correctly.

This message indicates that interface hme0 was added to IPMP group testgroup1. However, hme0 does not have a test address configured. To enable probe-based failure detection, you need to assign a test address to the interface.
May 24 14:09:57 host1 in.mpathd[101180]: No test address configured on interface hme0; disabling probe-based failure detection on it. testgroup1

This message appears for all interfaces with only IPv4 addresses that are added to an IPMP group.

May 24 14:10:42 host4 in.mpathd[101180]: 
NIC qfe0 of group testgroup1 is not 
plumbed for IPv6 and may affect failover capability

This message should appear when you have configured a test address for an interface.

Created new logical interface hme0:1
May 24 14:16:53 host1 in.mpathd[101180]: 
Test address now configured on interface hme0;
 enabling probe-based failure detection on it