Naming Convention of Cisco IOS Image Files

Naming Convention of Cisco IOS Image Files

The IOS is Internetworking Operating system software that runs on Cisco Routers and Switches. The IOS is stored in the flash memory. It is an image file having specific naming convention.

The below command shows the version of the IOS image: show version

router -

You can also see it using the below command: show flash

system flash -

The naming convention for the image file is in the format:



cXXXX: Platform

yyy: Feature Set

m: Memory Location

z: Compression format

123: Train Number

2:  Maintenance Release

1: Interim Build Number

a: Rebuild Letter

T: Train Identifier

1: Rebuid Number

Bin: Extension( binary)

The Examples for different platforms are mentioned below:

c1005 1005 platform

c1600 1600 platform

c1700 1700, 1720 and 1750 platform

c2500 25xx platform

c2600  2600 platform

c3620 3620 platform

c1500 1005 platform

c4500 4500 platform

The memory location codes:

f: image running from flash memory

m: image running from RAM

r: image running from ROM

l: image is relocatable during runtime

The compression codes:

z: zip format compression

x: mzip format compression

Codes in Feature Set

i: IP


2a2: ATM

b: Apple Talk

n: Novell

o: Firewall

p: Service Provider

v: Voice

so from the image name “c2600-i-mz.122-28.bin”, we understand that :

c2600  It’s a 2600 platform

i  IP Routing

mz  It shows that IOS is run from RAM and the compression is zip format

122-28 12.2 patch 28.

Read more

   CCNA Tutorial

   CCNA Practice Test