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Managing Oracle Solaris 11.1 Network Performance     Oracle Solaris 11.1 Information Library
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Document Information


1.  Introduction to Network Performance Management

2.  Using Link Aggregations

3.  Working With VLANs

4.  Administering Bridged Networks (Tasks)

5.  Introduction to IPMP

IPMP in Oracle Solaris

Benefits of Using IPMP

Rules for Using IPMP

IPMP Components

Types of IPMP Interface Configurations

How IPMP Works

IPMP Addressing

Data Addresses

Test Addresses

Failure Detection in IPMP

Probe-Based Failure Detection

Probe-Based Failure Detection Using Test Addresses

Probe-Based Failure Detection Without Using Test Addresses

Group Failure

Link-Based Failure Detection

Failure Detection and the Anonymous Group Feature

Detecting Physical Interface Repairs


IPMP and Dynamic Reconfiguration

6.  Administering IPMP (Tasks)

7.  Exchanging Network Connectivity Information With LLDP

8.  Working With Data Center Bridging Features in Oracle Solaris

9.  Edge Virtual Bridging in Oracle Solaris

10.  Integrated Load Balancer (Overview)

11.  Configuring Integrated Load Balancer

12.  Managing Integrated Load Balancer

13.  Virtual Router Redundancy Protocol (Overview)

A.  Link Aggregation Types: Feature Comparison

B.  Link Aggregations and IPMP: Feature Comparison


Failure Detection in IPMP

To ensure continuous availability of the network to send or receive traffic, IPMP performs failure detection on the IPMP group's underlying IP interfaces. Failed interfaces remain unusable until they are repaired. Remaining active interfaces continue to function while any existing standby interfaces are deployed as needed.

The in.mpathd daemon handles the following types of failure detection:

Probe-Based Failure Detection

Probe-based failure detection consists of using ICMP probes to check whether an interface has failed. The implementation of this failure detection method depends on whether test addresses are used.

Probe-Based Failure Detection Using Test Addresses

This failure detection method involves sending and receiving ICMP probe messages that use test addresses. These messages, also called probe traffic or test traffic, are sent over the interface to one or more target systems on the same local network. The in.mpathd daemon probes all the targets separately through all the interfaces that have been configured for probe-based failure detection. If no replies are made in response to five consecutive probes on a given interface, in.mpathd considers the interface to have failed. The probing rate depends on the failure detection time (FDT). The default value for failure detection time is 10 seconds. However, you can tune the FDT in the IPMP configuration file. For instructions, go to How to Configure the Behavior of the IPMP Daemon.

To optimize probe-based failure detection, you must set multiple target systems to receive the probes from the in.mpathd daemon. By having multiple target systems, you can better determine the nature of a reported failure. For example, the absence of a response from the only defined target system can indicate a failure either in the target system or in one of the IPMP group's interfaces. By contrast, if only one system among several target systems does not respond to a probe, then the failure is likely in the target system rather than in the IPMP group itself.

The in.mpathd daemon determines which target systems to probe dynamically. First, the daemon searches the routing table for target systems on the same subnet as the test addresses that are associated with the IPMP group's interfaces. If such targets are found, then the daemon uses them as targets for probing. If no target systems are found on the same subnet, then the daemon sends multicast packets to probe neighbor hosts on the link. The multicast packet is sent to the All Hosts multicast address, in IPv4 and ff02::1 in IPv6, to determine which hosts to use as target systems. The first five hosts that respond to the echo packets are chosen as targets for probing. If the daemon cannot find routers or hosts that responded to the multicast probes, then the daemon cannot detect probe-based failures. In this case, the ipmpstat -i command reports the probe state as unknown.

You can use host routes to explicitly configure a list of target systems to be used by the in.mpathd daemon. For instructions, refer to Configuring Probe-Based Failure Detection.

Probe-Based Failure Detection Without Using Test Addresses

With no test addresses, this method is implemented by using two types of probes:

Note - In Oracle Solaris, probe-based failure detection operates with test addresses. To select probe-based failure detection without test addresses, you must manually enable transitive probing. For the procedures, see How to Select Which Failure Detection Method to Use.

Group Failure

A group failure occurs when all interfaces in an IPMP group appear to fail at the same time. In this case, no underlying interface is usable. Also, when all the target systems fail at the same time and probe-based failure detection is enabled, the in.mpathd daemon flushes all of its current target systems and probes for new target systems.

In an IPMP group that has no test addresses, a single interface that can probe the active interface is designated as a prober. This designated interface has both the FAILED flag and PROBER flag set. The data address is bound to this interface, which enables the interface to continue probing the target to detect recovery.

Link-Based Failure Detection

Link-based failure detection is always enabled, provided that the interface supports this type of failure detection.

To determine whether a third-party interface supports link-based failure detection, use the ipmpstat -i command. If the output for a given interface includes an unknown status in its LINK column, then that interface does not support link-based failure detection. Refer to the manufacturer's documentation for more specific information about the device.

Network drivers that support link-based failure detection monitor the interface's link state and notify the networking subsystem when that link state changes. When notified of a change, the networking subsystem either sets or clears the RUNNING flag for that interface, as appropriate. If the in.mpathd daemon detects that the interface's RUNNING flag has been cleared, the daemon immediately fails the interface.

Failure Detection and the Anonymous Group Feature

IPMP supports failure detection in an anonymous group. By default, IPMP monitors the status only of interfaces that belong to IPMP groups. However, the IPMP daemon can be configured to also track the status of interfaces that do not belong to any IPMP group. Thus, these interfaces are considered to be part of an “anonymous group.” When you issue the ipmpstat -g command, the anonymous group is displayed as double-dashes (--). In anonymous groups, the interfaces have their data addresses also function as test addresses. Because these interfaces do not belong to a named IPMP group, then these addresses are visible to applications. To enable the tracking of interfaces that are not part of an IPMP group, see How to Configure the Behavior of the IPMP Daemon.