After going through the URLs below - I still don't have a good grasp of why global port mapping is required for Adaptive Session Redundancy. It seems that the pool of ports is required for the CSS to create connections on the back end - CSS to web server say having received from the client on the outside. The source port is drawn from those available. Have I got that much correct?
Why can't the CSS's in a pair just share a common pool of source ports - just as they share flow state information? Any insight appreciated. Thanks.
http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/css11500series/v7.10/configuration/advanced/guide/VIPRedun.html#wp1032233
http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/css11500series/v7.40/configuration/content_lb/guide/flow.html#wpmkr998649