Configure Extended Sequence Number (ESN)

You can use Extended Sequence Number (ESN) to increase the data transfer rate for a VPN connection.

If you use the AH protocol or the ESP protocol and AES as the encryption algorithm you might want to enable ESN. ESN allows you to transmit large volumes of data at a high speed with out re-keying. The VPN connection uses a 64-bit sequence numbers instead of 32-bit numbers over IPSec. Using 64-bit sequence numbers allows more time before re-keying, which prevents sequence number exhaustion and minimizes the use of system resources.

To enable ESN on a VPN connection follow these steps:

In iSeries™ Navigator, expand your server > Network > IP Policies > Virtual Private Networking
Right-click on Virtual Private Networking and select Properties.
On the General tab select Use Extended Sequence Number (ESN).