For link aggregation in ASA 8.0 you can setup logical redundant interface pairs as active and a standby physical interface. When the active interface fails, the standby interface becomes active and starts passing traffic. You can configure a redundant interface to increase the adaptive security appliance reliability. You can also configure a link standby ISP if the link to your primary ISP fails. It uses static routing and object tracking to determine the availability of the primary route and to activate the secondary route when the primary route fails.