9• A UDP jitter or a voice operation sends a number of probe packets. The number of probe packetsis set by using the probe packet-number command.• An FTP operation uploads or downloads a file.• An HTTP operation gets a Web page.• A DHCP operation gets an IP address through DHCP.• A DNS operation translates a domain name to an IP address.• An ICMP echo operation sends an ICMP echo request.• A UDP echo operation sends a UDP packet.• An SNMP operation sends one SNMPv1 packet, one SNMPv2c packet, and one SNMPv3 packet.• A path jitter operation is accomplished in the following steps:a. The operation uses tracert to obtain the path from the NQA client to the destination. Amaximum of 64 hops can be detected.b. The NQA client sends ICMP echo requests to each hop along the path. The number of ICMPecho requests is set by using the probe packet-number command.• A UDP tracert operation determines the routing path from the source to the destination. The numberof the probes to each hop is set by using the probe count command.CollaborationNQA can collaborate with the Track module to notify application modules of state or performancechanges so that the application modules can take predefined actions.Figure 6 CollaborationThe following describes how a static route destined for 192.168.0.88 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 static routing module of the state change.4. The static routing module sets the static route as invalid according to a predefined action.For more information about collaboration, see High Availability Configuration Guide.Application modulesVSRPDetectionmoduleNQASends thedetection resultsSends the trackentry statusTrackmoduleAssociates with adetection entryAssociates witha track entryTraffic redirectingVRRPStatic routingPolicy-basedroutingInterface backupWLAN uplinkdetectionSmart Link
