The Cisco Ether Switch service modules provide Cisco modular access routers the ability to stack Cisco Ether Switch service modules as Layer 2 switches using Cisco Stack Wise technology. The Cisco Ether Switch service modules are supported by either the IP base image (formerly known as standard multilayer image (SMI)) or the IP services image (formerly known as the enhanced multilayer image (EMI)). The IP base provides Layer 2+ features, including access control lists (ACLs), quality of service (Qo S), static routing, & the Routing Information Protocol (RIP). IP services provide a richer set of enterprise-class features, including Layer 2+ features & full Layer 3 routing (IP unicast routing, IP multicast routing, & fallback bridging). To distinguish it from the Layer 2+ static routing & RIP, IP services include protocols such as the Enhanced Interior Gateway Routing Protocol (EIGRP) & the Open Shortest Path First (OSPF) Protocol.