IP Phone Boot up process

1. IP phone obtains power from the switch

2. Phone loads stored image

3. Switch provides VLAN information to IP phone using CDP.

4. Phone sends DHCP(provides IP address,default gateway and DNS) request;receives IP information and TFTP(option 150) server address.

5. IP Phone gets configuration from TFTP server

6. IP Phone registers with Cisco CallManager server which includes primary,secondary and tertiary servers.

**NOTE: A simple flowchart for the better understanding.