This OCTET STRING identifies the type of probe (such as the service being tested) that generated an HP OpenView Internet Services trap, and is only accessible as part of a notification (accessible-for-notify). Admins use it to see what kind of service check triggered the alarm, such as HTTP, DNS, or ping. For example, hpOVISProbeType might report 'HTTP' to show the alert came from a web-service availability probe rather than a network-layer check.