Know more about Management Interfaces Storage networks STANDARDIZED AND PROPRIETARY MECHANISMS
Storage networks consist of two main types of devices • Connection devices Connection devices include the switches, hubs and bridges that are used to create the connections in the storage network.
• Endpoint devices Endpoint devices are the servers and storage devices that are connected to the connection devices. Devices – i.e. connection devices and endpoint devices – in a storage network are also called nodes because they seem to form the nodes of the network. Endpoint devices are
correspondingly called end nodes. The interfaces for the management of endpoint devices and connection devices are differentiated into in-band and out-band interfaces
• In-band All devices of a storage network have an in-band interface as standard. Devices are connected to the storage network via the in-band interface and data transfer takes place through this interface. In addition, management functions for discovery, monitoring and configuration of connection devices and endpoint devices are made available on this interface. These are generally realized in the form of components of the current
protocol of the in-band interface. Thus, for example, in a Fibre Channel SAN the Fibre Channel protocol makes the appropriate in-band management functions available. The use of these services for the management of storage networks is then called in-band management.
• Out-band Most connection devices and complex endpoint devices possess one or more further interfaces in addition to the in-band interface. These are not directly connected to the storage network, but are available on a second, separate channel. In general, these are LAN connections and serial cable. This channel is not intended for data transport, but is provided exclusively for management purposes. This interface is therefore called out-of-band or out-band for short. Management functions are made available over this additional interface using a suitable protocol. Thus Fibre Channel SAN devices generally have an additional LAN interface and frequently possess a serial port in addition to their Fibre Channel ports to the storage network. The use of the management services that are provided by means of the out-band interface is called out-band management. In-band and out-band have their advantages and disadvantages. Depending upon the implementation environment, either an in-band or an out-band anagement approach will fulfil its purpose better. This depends primarily upon the interfaces that the devices in the storage network possess. In some storage network environments, however, even the use of an additional out-band interface is not possible for security reasons or because there is no LAN connection, for example. A management system can operate one or both interfaces at the same time. This requires that it uses the appropriate protocol for each interface. In the following we now wish to first consider standardized and proprietary mechanisms (Section 8.5) and then consider in detail which mechanisms are available for in-band and out-band (Section 8.7) interfaces.
STANDARDIZED AND PROPRIETARY MECHANISMS
Standardized and proprietary mechanisms are used for the realization of management functions on in-band and out-band interfaces. Standardized mechanisms offer the advantage in relation to proprietary interfaces that management systems can address various devices via a unified interface. This means that the developer of a management system does not need to implement a proprietary mechanism in the software for each device, which is complicated and thus expensive. Proprietary mechanisms, on the other hand, have the advantage over standardized mechanisms that they can provide more management functions for a certain device and thus permit deeper and more device-specific management
interventions.
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