5.2 Managing the Cisco File System  
  5.2.2 IOS naming conventions  
Cisco develops many different versions of the IOS. The IOS supports varied hardware platforms and features. Cisco is also continuously developing and releasing new versions of the IOS.

To identify the different versions, Cisco has a naming convention for IOS files. This IOS naming convention uses different fields in the name. Among the fields are 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 this image is designed.

The second part of the IOS file name identifies the various features that this 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. Examples of feature-set categories are:

  • Basic – A basic feature set for the hardware platform, for example IP and IP/FW
  • Plus – A basic feature set plus additional features such as IP Plus, IP/FW Plus, and Enterprise Plus
  • Encryption – The addition of the 56-bit data encryption feature sets, such as Plus 56, to either a basic or plus feature set. Examples include IP/ATM PLUS IPSEC 56 or Enterprise Plus 56. From Cisco IOS Release 12.2 onwards, the encryption designators are k8/k9:
    • k8 – Less than or equal to 64-bit encryption in IOS version 12.2 and up
    • k9 – Greater than 64-bit encryption (on 12.2 and up)

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. As Cisco develops newer versions of the IOS, the numerical version number increases.

 

Interactive Media Activity

Drag and Drop: IOS Naming Conventions

When the student has completed this activity, the student will be able to identify the different fields in an IOS image name.

 
 

Web Links

Loading and Maintaining System Images

http://www.cisco.com/en/US/products/sw/ iosswrel/ps1835/products_configuration_guide_ chapter09186a00800c6c63.html#xtocid3