Example: option 43 to create a PXE boot menu

The administrator wants to display two lines in the PXE boot menu, pointing to two separate OS deployment servers. The two servers must use different PXE server type numbers or they will be seen as only one server by the PXE network card.

In addition to the standard PXE server type 15, OS deployment server accept any number between 33008 (80F0 in hexadecimal) and 33280 (8200 in hexadecimal). These new PXE server type numbers are used to differentiate multiple OS deployment servers in the BOOT_SERVERS sub-option of DHCP option 43.

In this example, the first server has the address 192.168.1.4 (C0:A8:01:04 in hexadecimal), and the second server, 192.168.1.5 (C0:A8:01:05 in hexadecimal).

Assign an OS deployment server type to each of the servers. OS deployment servers accept server type 15, and server types from 33008 to 33280. For this example, 33008 (80F0) is used for the first server, and 33009 (80F1) for the second server.
The sub-options of DHCP option 43 must then be configured as follows:
PXE option 6, length 1,value = 07

Value 7 means use PXE_BOOT_SERVERS list, disable multicast and broadcast discovery

PXE option 8, length 14 (0E), value = 80:F0:01:C0:A8:01:04:80:F1:01:C0:A8:01:05

Option 8 defines the two PXE servers. The first server is defined by the first 7 bytes, starting with the OS deployment server type (80:F0, 33008), followed by one IP address: C0:A8:01:05 (192.168.1.4). The second server is defined in the following manner, using OS deployment server type 80:F1 (33009).

PXE option 9, length 22 (16), value = 80:F0:08:53:65:72:76:65:82:20:41:80:F1:08:53:65:72:76:65:82:20:42

Option 9 defines the boot menu that is displayed at boot time. The first 11 bytes correspond to the first line, for the first server. It shows the string Server A, associated with type 80:F0 (first server). The second line shows the string Server B, associated with type 80:F1 (second server).

PXE option A, length 6, value =0F:53:65:6C:65:63:74

Option 10 (0A) specifies a 15 second timeout and shows the string Select as the boot menu prompt.

PXE option FF

To close the buffer.
The full option 43 reads as follow:
```
06:01:07:08:0E:80:F0:01:C0:A8:01:04:80:F1:01:C0:A8:01:05: 
09:16:80:F0:08:53:65:72:76:65:82:20:41:80:F1:08:53:65:72:76:65:82:20:42: 
0A:06:0F:53:65:6C:65:63:74:FF 
```

When your boot menu is displayed on your target screen, press F8 to make your selection.