What is SonicWall Discovery Protocol (SDP)?

Q: What is SonicWall Discovery Protocol (SDP)?

A: The SonicWall Discovery Protocol (SDP) is a layer 2 protocol employed by SonicPoints and devices running SonicOS. SDP is the foundation for the automatic provisioning of SonicPoint units via the following messages.

Advertisement

SonicPoint devices without a peer will periodically and on startup announce or advertise themselves via a broadcast. The advertisement will include information that will be used by the receiving SonicOS device to ascertain the state of the SonicPoint. The SonicOS device will then report the state of all peered SonicPoints, and will take configuration actions as needed.

Discovery

SonicOS devices will periodically send discovery request broadcasts to elicit responses from L2 connected SonicPoint units.

Configure Directive

A unicast message from a SonicOS device to a specific SonicPoint unit to establish encryption keys for provisioning, and to set the parameters for and to engage configuration mode.

Configure Acknowledgment

A unicast message from a SonicPoint to its peered SonicOS device acknowledging a Configure Directive.

Keepalive

A unicast message from a SonicPoint to its peered SonicOS device used to validate the state of the SonicPoint.

If via the SDP exchange the SonicOS device ascertains that the SonicPoint requires provisioning or a configuration update (e.g. on calculating a checksum mismatch, or when a firmware update is available), the Configure directive will engage a 3DES encrypted, reliable TCP based SonicWall Simple Provisioning Protocol (SSPP) channel. The SonicOS device will then send the update to the SonicPoint via this channel, and the SonicPoint will restart with the updated configuration. State information will be provided by the SonicPoint, and will be viewable on the SonicOS device throughout the entire discovery and provisioning process.