The management of services and operations in today s organizations are - coming increasingly dependent on their enterprise local area network (enterprise LAN). An enterprise LAN consists of a set of network zones (logical group of networkelements)correspondingto di?erent departments orsections, connected through various interface switches (typically, Layer-3 switches). The network service accesses between these zones and also with the external network (e. g., Internet) are governed by a global network security policy of the organization. This global policy is de?ned as a collection of service...