Web-Based Enterprise Management

Web Based Enterprise Management (WBEM) is a systems management architecture. The architecture is independent of the device being managed and has been applied to devices as diverse as IP Routers, Electrical Power Distribution Systems, Private Branch Exchanges (PBXs), Desktop Computers, Printers and Storage Servers.

The architecture has been standardised by the Distributed Management Task Force (previously the Desktop Management Task Force) - the DMTF.

To understand the WBEM architecture, consider the components which lie between the operator trying to manage a device (configure it, turn it off and on, collect alarms, etc.) and the actual hardware and software of the device:

1. the operator will presumably be presented with some form of graphical user interface (GUI), browser user interface (BUI) or command-line interface (CLI). The WBEM standard really has nothing to say about this interface (although a CLI for specific applications is being defined): in fact it is one of the strengths of WBEM that it is independent of the human interface since human interfaces can be changed without the rest of the system needing to be aware of the changes.
2. the GUI, BUI or CLI will interface with a WBEM client through a small set of Application Program Interfaces. This client will find the WBEM Server for the device being managed (typically on the device itself) and construct an XML message with the request.
3. the client will use the HTTP (or HTTPS) protocol to pass the request, encoding in CIM-XML, to the WBEM client
4. the WBEM server will decode the incoming request, perform the necessay authentication and authorisation checks and then consult the previously-created model of the device being managed to see how the request should be handled. This model is what makes the architecture so powerful: it represents the pivot point of the transaction with the client simply interacting with the model and the model interacting with the real hardware or software. The model is written using the Common Information Model (CIM) standard and the DMTF has published many models for commonly-managed devices and services: IP routers, Storage Servers, Desktop Computers, etc.
5. for most operations, the WBEM server determines from the model that it needs to communicate with the actual hardware or software. This is handled by so-called "providers": small pieces of code which interface between the WBEM server (using a standardised interface known as CMPI) and the real hardware or software. Because the interface is well-defined and the number of types of call is small, it is normally easy to write providers. In particular, the provider writer knows nothing of the GUI, BUI or CLI being used by the operator.

So, which pieces of this does a device manufacturer or service provider have to write?

• Firstly the model. This is normally done by extending as necessary one of the standard models published by the DMTF.
• Then the BUI, GUI or CLI.

The client and server do not need to be written because there are many open-source and commercial implementations available: try OpenPegasus or OpenWBEM, both of which are written in C++, but there are many others.

• Then the providers

In summary, the WBEM architecture allows the manufacturer of a device or developer of a service to provide a standards-compliant management interface to that device simply and cheaply.