The IOS naming convention

The IOS naming convention

5.2.2

This page will introduce the Cisco IOS naming convention. Students will learn why it is used and what each field represents.
There are many different versions of the Cisco IOS. The IOS supports varied hardware platforms and features. New versions of the IOS are continuously developed and released.
To identify the different versions, there is a naming convention for IOS files. This IOS naming convention uses different fields in the name. The fields include the hardware platform identification, the feature set identification, and the numerical release. 
The first part of the Cisco IOS file name identifies the hardware platform for which an image is designed.
The second part of the IOS file name identifies the various features that a file contains. There are many different features to choose from. These features are packaged in software images. Each feature set contains a specific subset of Cisco IOS features. Here are some examples of feature-set categories:

• Basic - A basic feature set for a hardware platform such as IP and IP/FW
• Plus - A basic feature set plus additional features such as IP Plus, IP/FW Plus, and Enterprise Plus
• Encryption - A 56-bit data encryption feature set, such as Plus 56, that is combined with a basic or plus feature set. Examples include IP/ATM PLUS IPSEC 56 or Enterprise Plus 56.

The encryption designators for Cisco IOS Release 12.2 or later are k8 and k9:

—k8 - Less than or equal to 64-bit encryption in IOS version 12.2 and later

—k9 - Greater than 64-bit encryption in IOS version 12.2 and later

The third part of the file name indicates the file format. It specifies if the IOS is stored in flash in a compressed format and whether the IOS is relocatable. If the flash image is compressed, the IOS must be expanded during boot as it is copied to RAM. A relocatable image is copied from flash into RAM to run. A non-relocatable image is run directly from flash.
The fourth part of the file name identifies the release of the IOS. The numerical version number increases for newer versions of the IOS.
The Interactive Media Activity will help students become familiar with the fields in an IOS image name.
The next page will show students how a TFTP server can be used to manage configuration files.