Section 7.1. The Common Information Model and WBEM

   

---

7.1 The Common Information Model and WBEM

Simple Network Management Protocol (SNMP) is a stable technology for management that has its advantages and disadvantages. SNMP has provided a reliable means for monitoring and raising events, but it has not been good at is modeling relationships and providing a proactive means of storage management.

In recognition of the need for a new systems management paradigm, Web-Based Enterprise Management (WBEM) was started as an industry initiative in 1996 and became an industry standard body initiative under the auspices of the Distributed Management Task Force (DMTF, formerly the Desktop Management Task Force). WBEM defines a model called the Common Information Model (CIM) that can also integrate existing standards such as SNMP and DMI (Desktop Management Interface).

WBEM defines a comprehensive Common Information Model that covers not just storage, but also networks and systems, as well as modeling the internal and external relationships between elements ”for example, the relationship between one storage device and another or that between a storage device and a system. CIM defines a series of schemas for defining management information and relationships between entities. The following list represents an illustrative (and not necessarily comprehensive) inventory of CIM schemas that are defined by the DMTF:

• CIM core

• CIM application

• CIM network

• CIM network QoS (quality of service)

• CIM user

• CIM storage

The important point is that the DMTF defines CIM as a model and not an implementation. In an effort to make CIM more attractive and provide cross-platform compatibility in a heterogeneous environment, the DMTF has also defined a way in which heterogeneous systems can exchange management information using HTTP as a transport and XML documents to contain the management information.

CIM is still evolving, and no doubt it will only grow in importance, especially given the recent CIM demonstrations by several vendors at the Storage Networking World conference in March 2002. The main problem that CIM has now is that management application vendors, as well as hardware vendors, are learning by trial and error. Hardware vendors do not have clear guidance as to what particular instrumentation needs to be developed, and management application vendors do not have clear direction as to what classes and instrumentation they can expect to have that will always be available or only sometimes available (depending on the vendors ). No doubt, time will smooth out this issue.

---

Top