session persistence enable

By default, the sticky session function is disabled for intelligent uplink selection.

You can configure an overload protection threshold for each intelligent uplink selection interface. When the bandwidth usage of a link reaches the overload protection threshold, the FW excludes the overloaded link when selecting routes for new traffic. The Internet access traffic of some users may have selected the link before it is overloaded, but the new session traffic (such as opening a new web page) is forwarded by another interface on the FW after the link is overloaded. In this case, the following phenomena may occur: Users need to re-log in after the accessed web pages are refreshed; online games are disconnected; and even some online banking services deny user access.

To resolve the preceding problems, enable the sticky session function.

After the sticky session function is enabled and a link is selected for the Internet access traffic of a user, the FW generates a sticky session entry accordingly. If new traffic matches the sticky session entry, the FW will forward the traffic out of the outgoing interface recorded in the sticky session entry. In doing so, the traffic of the same user is always forwarded through the same link.

After the sticky session function is disabled, the FW immediately deletes all sticky session entries of the corresponding intelligent route selection policy, which may cause link switchover for some users. Therefore, exercise with caution.

When a link involved in intelligent uplink selection is down, the sticky session entry of the link is immediately aged out, and the FW selects a normal link for subsequent traffic.