Reference Guide

4) Assume that OF Device Discovery was unable to determine the exact type of device in step 3.
Also assume in step 3 that it is determined that the device is manufactured by HP. OF Device
Discovery will interact with the Device Driver Manager to obtain the HP Device Identity
Handler Facet that can be used to interact with the device using SNMP to obtain additional
information.
5) The HP Device Identity Handler Facet must obtain the correct security key to interact with the
device. The Device Identity Handler Facet will obtain all SNMP security keys from the Key
Manager. It will try keys until it finds a key that allows it to get (read) SNMP objects from the
device. Note, trying all keys is only required the first time a Device Identity Handler Facet tries
to interact with a device. Once the correct key is determined, it is saved and will be used in
subsequent interactions with the device.
6) Once the correct SNMP key is discovered, the Facet will get several SNMP MIB objects from
the device to enable it to better identify the type of device. The sysObjectId is the MIB object
that will be used to determine the type of device.
7) OF Device Discovery will use this additional information and interact with the Device Driver
Manager to better determine the type of this device. The device type will be determined using
the sysObjectId and looking for a match in the Device Type data (i.e., XML data).
8) The type of device as well as other information discovered about the device (through SNMP or
through the OpenFlow information) is packaged in a DeviceInfo object. OF Device Discovery
will pass the DeviceInfo object to the Device Manager. The Device Manager will store or
update the Device information in its database, and share it with other team members if
configured to operation in a team.
9) Applications can use Device Service APIs to read device information and its associated
attributes.
Port-Interface Discovery
The discussion above focused on discovering devices and maintaining information about devices.
The Device Manager is also responsible for maintaining information about port-interfaces
associated with a device. It is the responsibility of the Discovery components to obtain the port-
interface information and provide it to the Device Manager.
How the port-interface information is discovered and kept up to date is the responsibility of the
Discovery component. Different techniques will be used depending on the type of Discovery
component. For example, OF Device Discovery will obtain port-interface information using the
Controller Service API. When a new OpenFlow device is discovered, OF Device Discovery will
obtain the port-interface information from the Controller Service. It will also register with the
Controller Service to receive notifications when a port-interface is added, deleted, or the port-
interface’s status changes.
For non-OpenFlow devices, the interface information can be collected by a Facet using SNMP.
Any status changes on the ports discovered can be notified through SNMP Traps if the controller is
enhanced to be an SNMP Receiver.
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