DPI subagent UNREGISTER request

A subagent can unregister a previously registered subtree. The subagent must specify the following parameters in the UNREGISTER request:

The subtree to be unregistered.
Object level unregistration: This is a null-terminated string in the selected character set specifying the subtree that is to be unregistered. Object level unregistration requires a trailing period, which is following the object number, indicating an unregister request to all supported instances of an object (for example, ifDescr). Object level unregistration requires that the subtree must have a trailing period. For example: 1.3.6.1.2.1.2.2.1.2.

Instance level unregistration: Instance level unregistration does not require a trailing period for the subtree.
Note: Unregistration at the instance level can be done only if the original registration was done using instance level registration.
Unregistration by subagent at the instance level, rather than the object level, is accomplished by adding the instance number after the object number when building the unregistration packet using the mkDPIunregister call. For example, passing the object number 1.3.6.1.2.1.2.2.1.2. (note the ending period) would support all instances of ifDescr. However, a subagent can pass an object or instance number 1.3.6.1.2.1.2.2.1.2.8 (note the addition of the 8 after the period) to support only ifDescr.8 (instance 8).
The reason for the unregister. See DPI UNREGISTER reason codes for a list of valid reason codes.

After a subagent has sent a DPI UNREGISTER packet to the agent, it should expect a DPI RESPONSE packet that informs the subagent about the result of the request. The packet ID of the RESPONSE packet should be the same as that of the REGISTER packet to which the RESPONSE packet is the response. See DPI RESPONSE error codes for a list of valid codes that can be expected.

A subagent should also be prepared to handle incoming DPI UNREGISTER packets from the agent. In this situation, the DPI packet contains a reason code for the UNREGISTER request. A subagent does not have to send a response to an UNREGISTER request. The agent assumes that the subagent will handle it appropriately. The registration is removed regardless of what the subagent returns.

See the following related information.

SNMP DPI: Processing an UNREGISTER request