Network and system administrators looking to monitor and manage devices have a choice of two popular methods:

  1. Simple Network Management Protocol (SNMP is part of the TCP/IP network protocol).
  2. Windows Management Instrumentation (WMI), part of the infrastructure for management data and operations on Windows-based operating systems.

Both of these protocols are very fast and highly efficient, but they go about their business in very different ways. This can lead to confusion about which technology is best. So we created this Q&A article to answer the questions many network administrators have about each solution. Use the answers here to help you choose the right solution for your network, alternatively, contact us and we can help guide you to making the right decisions.
Ultimately for managing Windows devices while SNMP can be used, WMI is probably the better option, while SNMP is widely supported by networking vendors like Cisco, Juniper, Huawei and Unix/Linux operating systems.

Windows Management Instrumentation (WMI)

Why use WMI?

Windows Management Instrumentation (WMI) is the Microsoft implementation of the Web-Based Enterprise Management (WBEM) framework. It is designed to help network administrators manage Window OS devices on a distributed network. Administrators can use WMI to perform several administrative tasks such as making registry changes and carrying out inventory checks.

On the face of it, WMI performs similar tasks to SNMP but it provides a higher level of representation of systems. For example, WMI supports properties, events and methods on top of the object classes used by SNMP. The downside is that WMI only works on devices running Windows OS and has increased network overhead compared to SNMP.

What is WMI?

WMI forms part of the Microsoft Management Toolkit. It contains a suite of tools and extensions which provide information about the desktops and servers located on the network. Administrators can also extend the capability of the framework by writing scripts in VBScript or PowerShell.

How does WMI work?

WMI is an implementation of the Web-based Enterprise Management (WBEM) standard. This was developed by the Distributed Management Task Force (DMTF) to help bring uniformity to the management of distributed networks.

The WMI standard uses a web-based approach for exchanging data across platforms. Data is encoded using Extensible Markup Language (XML) and transmitted between the WMI repository and clients using the Hypertext Transfer Protocol (HTTP).

WMI deployments can be either agent-based or agentless giving network admins the option of creating a monitoring solution which fits their operational needs and budget. Agents provide more comprehensive monitoring than using an agentless approach, but the cost and complexity of installing and managing such a solution may be prohibitive.

Which layer does WMI work on?

The WBEM standard uses HTTP to transmit data on layer 7, the application layer of the OSI model.

When was WMI released?

WMI was introduced in Windows NT 4.0 SP4 in October 1998. The framework has been updated with every major release of the Windows Operating System. Early versions of the framework required scripts to be written in VBScript which made it difficult to manage. But the latest version is fully compatible with PowerShell, making it much easier for admins to use.t

When to use WMI

WMI is the preferred choice for managing large distributed Window OS based networks. It provides more detailed diagnostics and analytics compared to using SNMP. The downside is that it requires a larger skillset from administrators and uses more network bandwidth.

What are WMI queries?

WMI queries are used by network admins to get data out of the WMI repository. To write queries admins must have a good understanding of WMI Query Language (WQL). There are three types of query: Data Queries, Event Queries and Schema Queries.

What language is used for WMI databases?

The WMI database (repository) uses the WMI Query Language (WQL) for queries. This uses a syntax similar to SQL which is used by many popular database applications. If administrators require help building queries they can consult the WMI Query Wizard (WMIX) which is built into the framework.

What are WMI scripts?

WMI scripts are used to view or manipulate information in the repository which cannot be accessed via a standard query. Scripts can be written in any language that supports Microsoft ActiveX scripting. This includes popular scripting languages such as VBScript, Perl and PowerShell.

What are WMI filters?

With today’s enterprise networks containing a diverse range of hardware and operating systems, admins must filter systems based on their underlying architecture. This is where WMI filters come into play. WMI filters can be used to find specific operating systems, processors, registry settings and IP ranges.

What are WMI monitoring tools?

Because WMI can be difficult to manage, especially if admins don’t have the necessary scripting knowledge, many companies have developed WMI monitoring tools. These provide a graphical user interface to display and manipulate the data in the repository. Some tools also allow you to build scripts without any coding knowledge.

What can WMI monitor?

WMI can be used to monitor any desktop or server running Windows OS in public, private or hybrid environments. The solution provides in-depth analysis of devices including current configuration parameters, status values, CPU load, memory usage, software and hardware audits, application availability and operating system failures.

Which WMI version is best?

WMI is a management framework built into the Windows Server installation, so you should always have the latest version installed. All new releases of the framework are backwards compatible with previous versions so they should work out of the box without any major configuration changes.

Simplicity vs. flexibility

So which monitoring solution is right for you? The answer will depend on the size and complexity of your network, the skills of your network administrators and your available budget.

One of the major advantages of SNMP is that it is easy to deploy and configure even on larger networks. It can also be used to manage all devices on the network regardless of the manufacturer. Many SNMP tools are also free which helps keep costs down. The downside is that standard SNMP features are very basic.

If you require more sophisticated data and configuration options and you operate a large Windows OS environment, then WMI is the way to go. This will provide you with a powerful framework to streamline the monitoring and management of your Windows OS environment. The downside is more complexity and increased operational overhead.