The following are the DHCP rules in the auto-provisioning stage:
First, auto-provisioning walks through the interfaces with a configured port, where the port is in operational status up, one by one.
It sends a DHCP request to the first configured interface with a port up and no IP address configured.
If, on this interface, multiple DHCP offers arrives, only the first offer is sent to the auto-provisioning task and the other offers are ignored. This could occur if the node is on a LAN and multiple DHCP servers are connected to the interface.
The DHCP client has an exponential retry mechanism. If the DHCP offer does not arrive from the server, the client resends a DHCP request at 2, 4, 8, 32 and 64 s, with 64 s being the maximum timeout, If the 64 s timeout interval is reached, the DHCP client keeps retrying every 64 s. The user can configure a timeout value. If no DHCP offer has arrived by this timeout value, the auto-provisioning process moves to the next interface.
If the DHCP offer arrives on the port and the DHCP client task does not acknowledge the DHCP offer, for any reason, it disables the DHCP client and remove the IP from the port.
If the DHCP offer arrives on the port and the DHCP client acknowledges the offer, it sends the information to auto-provisioning. If auto-provisioning does not like the offer, because there is no Option 67, Option 67 is malformed, or for any other reason listed in Auto-provisioning Failure, the auto-provisioning process deconfigures the DHCP client and the DHCP client sends a DHCP release, and unassigns the IP address.
In case of failure, more information is displayed by the auto-provisioning process and the process moves to the next port that is up and does not have an IP address.
If auto-provisioning is successful using the offer and its option, the provisioning file download starts though the protocol dictated by Option 67.
The auto-provisioning command is CLI blocking. All information about the auto-provisioning process is displayed on the CLI and logged.