Detail the boot up process for an IP phone.
1. 802.3af PoE sends voltage, detects device and supplies power to the line.
2. Switch delivers voice VLAN info via CDP.
3. IP phone does DHCP dance with DHCP server, DHCP adds option 150 (TFTP server IP address).
4. Phone contacts TFTP server and gets config file and firmware.
5. Based on config file, phone registers with call precessing server(s). 1, 2, 3, repeat in big deployments. CME rtr in smaller deployments.