The ANSI T11 Fibre Channel Generic Services (FC-GS) specification series defines several services that augment the functionality of FC-SANs. Among these is an in-band management service. The FC Management Service is actually composed of many supporting services. The FC Management Service currently includes:
The FC Management Service is distributed. It typically runs on the FC switches that compose a fabric. Each switch in a fabric maintains an identical copy of the management information for the entire fabric. This enables a single point of access for management of an FC-SAN. In other words, a management application (such as a fabric manager) can connect to a single switch to access all management information for all switches in the fabric.
The Fabric Configuration Server supports discovery of the fabric topology and operating characteristics. When a fabric manager connects to a FC switch, connectivity information for all devices in the fabric is visualized using data extracted from the Fabric Configuration Server. The Performance Server collects and aggregates performance statistics for the entire fabric. Management applications can query any FC switch to access performance statistics for the entire fabric. The Performance Server also supports threshold monitoring. As discussed in Chapter 12, "Storage Network Security," the Fabric Zone Server restricts communication between devices attached to an FC-SAN. Though FC zones are security-focused, the Fabric Zone Server is integral to the management service. This is because the Fabric Zone Server is the mechanism by which FC zones are configured and managed. The Security Policy Server facilitates the definition and management of security policies related to the Fibre Channel Security Protocols (FC-SP) specification. The Unzoned Name Server provides full access to the FC Name Server (FCNS) database for management applications. Initiators and targets are subject to zone policies that restrict access to the information in the FCNS database. However, management applications require unrestricted access to the FCNS database. The HBA Management Server enables HBAs to register certain data (called HBA management information) with the FC fabric. This enables management applications to query the FC fabric for HBA management information instead of querying the end nodes directly. The mechanisms for HBA management information registration and retrieval are defined by the Fabric Device Management Interface (FDMI).
A standard Application Programming Interface (API) for HBAs complements the FC Management Service. The so-called HBA API is defined in the ANSI T11 SM-HBA specification. It supports direct management of HBAs. Vendor-supplied agents implement proprietary APIs. A standard API enables management application vendors to write software without the overhead of HBA-specific API calls. Thus, the HBA API enables management applications to discover, monitor, and manage heterogeneous HBAs consistently across disparate operating systems and server platforms. Note that the same information can be gathered from the FC fabric via the Performance Server, the HBA Management Server, and the FCNS.
The FC-GS specification series also defines a notification service called the Event Service. Fabric attached devices can register with the Event Server to receive notification of events. Currently, a limited number of events are supported. Like the FC Management Service, the Event Service is distributed.
The FC-LS specification defines various Extended Link Service (ELS) commands that can be issued by a fabric device to ascertain state information about devices, connections, Exchanges, and sequences. Examples include Read Exchange Status Block (RES), Read Sequence Status Block (RSS), Read Connection Status (RCS), Read Link Error Status Block (RLS), and Read Port Status Block (RPS). These commands are issued directly from one device to another.