Naming Convention of Cisco IOS Image Files

IOS is the Operating System software used on Cisco routers and current Cisco Network Switches.Cisco IOS (Internetwork Operating System) image file is normally stored in flash memory and it has a naming convention.

Following output shows the "show-flash" command from privileged mode.

OmniSecu03#show flash
System flash directory:
  File  Length   Name/status

  3   5571584   c2600-i-mz.122-28.bin

  2   28282     sigdef-category.xml

  1   227537    sigdef-default.xml

                    [5827403 bytes used, 58188981 available, 64016384 total]

                    63488K bytes of processor board System flash (Read/Write)

• The name of the Cisco IOS (Internetwork Operating System) file is c2600-i-mz.122-28.bin.

• The "c2600" means that this IOS image is for a 2600 series router. Other values which may appear here for different router platforms are listed below.

c1005 – For 1005 platform

c1600 – For 1600 platform

c1700 – For 1700 series platforms

c2500 – For 2500 series platforms

c2800 – For 2800 series platform

c2900 – For 2900 series platforms

c3620 – For 3620 platform

c3640 – For 3640 platform

c4000 – For 4000 series platform

c4500 – For 4500 and 4700 platforms

• The "i" indicates  that this is the IP routing version of the IOS.

Normal values which may appear here are

a - appn

a2 – atm

a3 – SNA switching

b – appletalk

c – communications servers etc

i – ip

j – enterprise

l – IPX

n – Novell

o – firewall

p – service provider

v – voice

• The "mz" indicates that this version of the IOS runs from RAM and the IOS file is compressed.

• The "122-28" indicates that this is IOS version 12.2, patch level 28.