Despite these similarities, there are significant differences in the ways BOOTP and DHCP perform client configuration:
BOOTP supports a limited number of client configuration parameters called vendor extensions, while DHCP supports a larger and extensible set of client configuration parameters called options.
BOOTP uses a two-phase bootstrap configuration process in which clients contact BOOTP servers to perform address determination and boot file name selection, and clients contact Trivial File Transfer Protocol (TFTP) servers to perform file transfer of their boot image. DHCP uses a single-phase boot configuration process whereby a DHCP client negotiates with a DHCP server to determine its IP address and obtain any other initial configuration details it needs for network operation.
BOOTP clients do not rebind or renew configuration with the BOOTP server except when the system restarts, while DHCP clients do not require a system restart to rebind or renew configuration with the DHCP server. Instead, clients automatically enter the Rebinding state at set timed intervals to renew their leased address allocation with the DHCP server. This process occurs in the background and is transparent to the user.
