ZTP: Bootstrapping using HTTP proxy server in phone-home client

When the phone-home client (PHC) receives information regarding the HTTP proxy server through either DHCP option 43 suboption 8 or DHCP option 17 suboption 8, it creates an HTTPS transparent tunnel with the proxy server. After the tunnel is established, the PHC uses the tunnel as a proxy for the phone-home server or redirect server. The phone-home client downloads the software image and configuration file through the tunnel onto the device. When bootstrapping is complete, the device reboots and the tunnel quits.