What does mz mean in an ios filename

Add-on features are flavor specific. Two IOS may contain some similar features or may contain completely different features. Because of the hardware difference, Cisco compiles different IOS images for different platforms and models. A low-end router or a fixed chassis router with limited physical interfaces needs different IOS software to support its interfaces than a high-end router or a modular chassis router that supports many different types of interfaces. Cisco builds the IOS as a single image file.

Instead of releasing bug fixes and updates separately, Cisco compiles them into the IOS image file and releases a new IOS file incorporating those changes. It means, to add a bug fix, to move to a new release, or to move to a new version, you have to download and install a whole new IOS image file. However, if you know the naming convention that Cisco uses to compile its IOS image files, this process is not difficult.

Cisco assigns a unique name to each IOS image file. This name provides the following information: -. To release the major updates and minor bug fixes, Cisco uses the terms: version and release, respectively. Let's take an example to understand this naming convention in more detail. Access the CLI prompt of your router.

If you don't have a real Cisco router, you can use the Packet Tracer. Packet Tracer is a network simulator software. It allows you to practice with essential Cisco devices in a simulated environment.

You can download the latest version of the Packet Tracer from the following web page. Download the Packet Tracer for Windows and Linux. Access the privileged-exec mode and run the "show version" command.

The output of this command, along with other information, contains the name of the IOS file that is currently running on the router. A router stores IOS files into the flash memory. You can also use the "show flash" command to view all available IOS files. Cisco creates a separate IOS for each series of routers. Because of this, each IOS works only on the router belonging to that series.

The first term indicates the series of routers for which the IOS file is compiled. The word 'c' indicates that this IOS file is compiled for the series routers. In this case, universal refers to the universal, single image set, which includes IP Base, Security, Unified Communication, and Data feature sets.

Each router is activated for IP Base feature set. However, for other feature sets, software activation is needed. SPA - Designates that file is digitally signed by Cisco. M3 - Specifies the filename format for the image This is the version of IOS, which includes the major release, minor release, maintenance release, and maintenance rebuild numbers. The M indicates this is an extended maintenance release. The most common designation for memory location and compression format is mz.

The first letter indicates the location where the image is executed on the router. The locations can include:. The compression format can be either z for zip or x for mzip. Zipping is a method Cisco uses to compress some run-from-RAM images that is effective in reducing the size of the image. It is self-unzipping, so when the image is loaded into RAM for execution, the first action is to unzip.

Note : The Cisco IOS Software naming conventions, field meaning, image content, and other details are subject to change. On most Cisco routers including the integrated services routers, the IOS is stored in compact flash as a compressed image and loaded into DRAM during boot-up.

For complete details, refer to the product data sheet for the specific router.