PXE = Preboot Execution  Environment. 

PXE boot process:
1. Modified [[DHCP]] request: request to include boot information (PXE boot request).
2. Process DHCP response which includes an IP address of [[TFTP]] server and filename of [[NBP]].
3. Download NBP over TFTP.
4. NBP executes
	1. Loads additional stuff over network, like kernel images.
	2. Handles the boot menu
5. Kernel takes over boot process and potentially downloads additional files required to complete booting.

Popular NBP's:
- PXELINUX
- iPXE
- GRUB2