IP Monitoring Overview
This section describes how to keep track of the status of the system in use.
This feature monitors IP on standalone SRX Series Firewalls or a chassis cluster redundant Ethernet (reth) interface. Existing RPM probes are sent to an IP address to check for reachability. The user takes action based on the reachability result. Supported action currently is preferred static route injection to system route table.
The actions supported are:
Adding or deleting a new static route that has a higher priority (lower preference) value than a route configured through the CLI command
set routing-options static routeDefining multiple probe names under the same IP monitoring policy. If any probe fails, the action is taken. If all probes are reachable, the action is reverted
Configuring multiple tests in one RPM probe. All tests must fail for the RPM probe to be considered unreachable. If at least one test reaches its target, the RPM probe is considered reachable
Configuring multiple failure thresholds in one RPM test. If one threshold is reached, the test fails. If no thresholds are reached, the test succeeds.
Specifying the no-preempt option. If the no-preempt option is specified, the policy does not perform preemptive failback when it is in a failover state or when the RPM probe test recovers from a failure.
Setting preferred metric values. If the preferred metric value is set, during failover, the route is injected with the set preferred metric value.
Enabling and disabling interfaces.
Interface-Enable—On a physical or logical interface, when the interface-enable action is configured, the initial state of the interface is disable after startup, and it continues to remain in the disable state as long as the associated RPM probe is in the pass state. When the associated RPM probe fails, the configured physical and logical interfaces are enabled.
Interface-Disable—On a physical or logical interface, when the interface-disable action is configured, the interface state remains unchanged. When the associated RPM probe fails, the physical and logical interfaces are disabled.
Multiple probe names and actions can be defined for the same IP monitoring policy.
IP Monitoring Test Parameters
Each probed target is monitored over the course of a test, which represents a collection of probes during which statistics such as standard deviation and jitter are collected are calculated. During a test, probes are generated and responses collected at a rate defined by the probe interval, the number of seconds between probes.
To avoid flap, an action is reverted only at the end of a test cycle. During the test cycle, if no threshold is reached, the action is reverted. Although action-failover takes place based on a predefined condition of a monitored IP, when the condition is reversed, the IP becomes reachable on the original route, and the newly added route is deleted. Recovery is performed only when all RPM probes report the IP as reachable.
#id-understanding-ip-monitoring-test-parameters__ip-parameter-default-value lists the test parameters and its default values:
|
Parameter |
Default Value |
|---|---|
|
probe-count |
1 |
|
probe-interval |
3 seconds |
|
test-interval |
1 second |
#id-understanding-ip-monitoring-test-parameters__ip-monitor-threshold-supported lists the supported threshold and its description:
|
Threshold |
Description |
|---|---|
|
Successive-Loss |
Successive loss count of probes |
|
Total-Loss |
Total probe lost count |
IP Monitoring Through Redundant Ethernet Interface Link Aggregation Groups
IP monitoring checks the reachability of an upstream device. It is designed to check the end-to-end connectivity of configured IP addresses and allows a redundancy group (RG) to automatically failover when the monitored IP address is not reachable through the redundant Ethernet. Both the primary and secondary devices in the chassis cluster monitor specific IP addresses to determine whether an upstream device in the network is reachable.
A redundant Ethernet interface contains physical interfaces from both the primary and secondary nodes in the SRX Series chassis cluster. In a redundant Ethernet interface, two physical interfaces are configured with each node contributing one physical interface. In a redundant Ethernet interface LAG, more than two physical interfaces are configured in the redundant Ethernet interface.