Learn more on Standardized mechanisms and Proprietary mechanisms

Learn more on Standardized mechanisms and Proprietary mechanisms

 Standardized mechanisms

Many standardization organizations invest a great deal of development work in the standardization of management interfaces. For in-band management the developments occur on different protocol levels:

• In-band transport levels The management interfaces for Fibre Channel, TCP/IP and InfiniBand are defined on the in-band transport levels. In Section 8.6.1 we will discuss in detail the management interface of the transport levels of the Fibre Channel protocol.

• In-band upper layer protocols (ULP) Primarily SCSI variants such as Fibre Channel FCP and iSCSI are used as an upper layer protocol. SCSI has its own mechanisms for requesting device and status information: the so-called SCSI Enclosure Services (SES). In addition to the management functions

on transport levels a management system can also operate these ULP operations in order to identify an end device and request status information.

Special protocols such as SNMP (Section 8.7.1) and WBEM with CIM (Section 8.7.2) as well as SMI-S (Section 8.7.3) are used for the out-band management.

 Proprietary mechanisms

The proprietary (this generally means manufacturer-specific and usually even device specific) mechanisms fall into three categories:

• APIs In this approach, individual devices have programming interfaces – so-called Application Programming Interfaces (APIs) – which they can use to call up special management functions. They are generally implemented out-band. It requires a considerable development and testing cost to be able to use these APIs in a central management system. The manufacturers of management systems must develop appropriate software

modules for various device APIs in order to access the management functions of each. This increases the complexity and the costs of such a management system. Some manufacturers do not shy away from this cost. The advantage of such an approach can be a device-near support of the management system. Thus such a management system can supply better results than one that only operates standardized mechanisms.

• Telnet Many devices can also be configured out-band via Telnet. Although Telnet itself is not a proprietary mechanism, it is subject to the same problems as an API regarding connection to a central management system. For this reason we will count it amongst the proprietary mechanisms.

• Element manager An element manager is a device-specific management interface. It is frequently found in the form of a GUI (graphical user interface) on a further device or in the form of a WUI (web user interface) implemented over a web server integrated in the device itself. Since the communication between element manager and device generally takes place via a separate channel next to the data channel, element managers are classified amongst the out-band management interfaces. Element managers have largely the same disadvantages in a large heterogeneous storage network as the proprietary APIs. How- ever, element managers can be more easily integrated into a central management system than can an API. To achieve this, the element manager only needs to know and call up the appropriate start routines. WUIs are started by means of the Internet browser.

To call up a GUI this must be installed upon the computer on which the management system runs. In that way element managers to a certain degree form the device-specific level in the software architecture of the management system. In the following we will look in more detail at the standardized mechanisms and how these are used for in-band (Section 8.6) and out-band management (Section 8.7). Let us begin with in-band management.