port systems that provide capabilities, such as management of EVCs, inventory management, fault management, configuration management, and tools that allow the Service Level Agreement (SLA) to be managed. For many providers this means element management systems and network management systems that communicate via well-defined interfaces, such as those being developed by the TeleManagement Forum (TMF). Operations, Administration, and Maintenance (OAM) tools that provide both always- on monitoring tools and on-demand diagnostics. This has been traditionally viewed as a major weakness for Ethernet in the WAN environment compared to other technologies, and there has been considerable work carried out by standards bodies in recent years to address this, which is described in this chapter. The description of SLAs in terms of standardized parameters. Survivability mechanisms that enable service level agreements to be met. Security features such as isolation of control and management capabilities between the network provider and the customer, access security (e.g., role-driven operator permissions, authentication, audit trails, admission control lists), configuration security (including configuration history and change control), mechanisms to prevent denial of service, protection against MAC address spoofing, port security, and many others. In-Service Software Upgrades (ISSUs) that do not impact traffic. Redundant and hot-swappable components, such as switch fabrics, power supply units, control cards, and fans. An implementation should avoid single points of failure. It should be evident that this is not an exhaustive list, but at the same time it allows some variation of how an implementation can be seen as supporting carrier-grade capabi- lities. In what follows we will consider a service framework that provides a means of Ethernet Service Framework Ethernet Virtual Connection Customer Customer Metro Ethernet Network Fig. 14.1 Simplified view of the Ethernet services model. describing Ethernet service features in a manne