Providing authentication

If you need to provide authentication, you can use IPSec, which includes an authentication scheme. You can use IPSec authentication in one of the following ways:

Stand-alone
In combination with IPSec encryption
In combination with SNA session-level encryption

Using IPSec's authentication scheme lets the system performing authentication verify that the data is received from the partner and has remained unchanged during transmission. When you use IPSec's authentication scheme in combination with encryption, you can authenticate the partner before wasting extra cycles for data decryption.

Tip: SNA also offers Message Authentication Code (MAC), but it does not authenticate the IP header portion.