NQA features

Ping uses only the Internet Control Message Protocol (ICMP) to test the reachability of the destination host and the round-trip time. As an enhancement to ping, NQA supports more test types and functions.

NQA supports 11 test types: ICMP echo, DHCP, DNS, FTP, HTTP, UDP jitter, SNMP, TCP, UDP echo, voice, and DLSw.

NQA enables the client to send probe packets of different test types to detect the protocol availability and response time of the peer. Test results help you understand network performance.

Collaboration is implemented by establishing reaction entries to monitor the detection results of NQA probes. If the number of consecutive probe failures reaches a limit, NQA informs the track module of the detection result, and the track module triggers other application modules to take predefined.

The collaboration comprises the following parts: the application modules, the track module, and the detection modules.

• A detection module monitors objects, such as the link status, and network performance, and informs the track module of detection results.

• Upon the detection results, the track module changes the status of the track entry and informs the associated application module. The track module works between the application modules and the detection modules. It hides the differences among detection modules from application modules.

• The application module takes actions when the tracked object changes its state.

The following describes how a static route is monitored through collaboration.

1. NQA monitors the reachability to 192.168.0.88.

2. When 192.168.0.88 becomes unreachable, NQA notifies the track module of the change.

3. The track module notifies the state change to the static routing module

4. The static routing module sets the static route as invalid.

For more information about collaboration and the track module, see High Availability Configuration Guide.

NQA supports threshold monitoring for performance parameters such as average delay jitter and packet round-trip time. The performance parameters to be monitored are monitored elements. NQA monitors threshold violations for a monitored element, and reacts to certain measurement conditions (for example, sending trap messages to the network management server). This helps network administrators understand the network service quality and network performance.

• Monitored elements

  describes the monitored elements and the NQA test types in which the elements can be monitored.

• Threshold types

  The following threshold types are supported:

  • average—Monitors the average value of monitored data in a test. If the average value in a test exceeds the upper threshold or goes below the lower threshold, a threshold violation occurs. For example, you can monitor the average probe duration in a test.

  • accumulate—Monitors total number of times the monitored data violates the threshold in a test. If the total number of times reaches or exceeds a specific value, a threshold violation occurs.

  • consecutive—Monitors the number of consecutive times the monitored data violates the threshold since the test group starts. If the monitored data violates the threshold consecutively for a specific number of times, a threshold violation occurs.

  The counting for the average or accumulate threshold type is performed per test, but the counting for the consecutive type is performed after the test group starts.

• Triggered actions

  The following actions may be triggered:

  • none—NQA only records events for terminal display. It does not send trap information to the network management server. NQA DNS tests do not support the action of sending trap messages. The action to be triggered in DNS tests can only be the default one, none.

  • trap-only—NQA records events and sends trap messages to the network management server.

• Reaction entry

  In a reaction entry, a monitored element, a threshold type, and the action to be triggered are configured to implement threshold monitoring.

  The state of a reaction entry can be invalid, over-threshold, or below-threshold, using the following workflow:

  • Before an NQA test group starts, the reaction entry is in the state of invalid.

  • After each test or probe, threshold violations are counted according to the threshold type and range configured in the entry. If the threshold is violated consecutively or accumulatively for a specific number of times, the state of the entry is set to over-threshold. Otherwise, the state of the entry is set to below-threshold.

  If the action to be triggered is configured as trap-only for a reaction entry, when the state of the entry changes, a trap message is generated and sent to the network management server.