Background Reading on UDP Encapsulation of ESP Packets (NDIS 5.1)
Note NDIS 5. x has been deprecated and is superseded by NDIS 6. x. For new NDIS driver development, see Network Drivers Starting with Windows Vista. For information about porting NDIS 5. x drivers to NDIS 6. x, see Porting NDIS 5.x Drivers to NDIS 6.0.
To comprehend this section, you must understand the Internet Key Exchange (IKE) and the UDP encapsulation of ESP packets, as specified in the following drafts published by the IP Security Working Group of the Internet Engineering Task Force (IETF):