When NAT uses a route map to decide to create a translation entry, it will always create a "fully extended" translation entry. This translation entry will contain both the inside and outside (local and global) address entries and any TCP or UDP port information. Refer to NAT: Local and Global Definitions for more information on inside and outside (local and global) addresses.
When NAT uses an access list to decide to create a translation entry, it will create a "simple" translation entry. This "simple" entry will only contain local and global IP address entries for just the inside or outside depending on whether the ip nat inside or ip nat outside command is configured. Also, it will not include any TCP or UDP port information.
When NAT uses an access list, and overload has also been specified, NAT will create a "fully extended" translation entry. (Refer to Note1 ). The operation is similar to the route-map case except that route-map has some additional features. Refer to Note 2 for more details. You can see an example of a simple NAT translation entry and a fully extended NAT translation entry by selecting one of the links below: