Understanding the IOS File Name Convention

As a network guy we should know about the naming convention of the IOS file name, which is usually similar to this form:

xxxx-yyy-ww.aaa-bb.bin

1. The xxxx is the platform, For example,

c1005 – For 1005 platform

c1600 – For 1600 platform

c1700 – For 1700, 1720, and 1750 platforms

c2500 – For 25xx, 3xxx, 5100, and AO (11.2 and later only) platforms

c2600 – For 2600 platform

c2800 – For Catalyst 2800 platform

c2900 – For 2910 and 2950 platforms

c3620 – For 3620 platform

c3640 – For 3640 platform

c4000 – For 4000 platform (11.2 and later only)

c4500 – For 4500 and 4700 platforms



2. The yyy is the feature set. For example,

b For Apple talk support

boot For boot image

c For CommServer lite (CiscoPro)

drag For IOS based diagnostic image

g For ISDN subset (SNMP, IP, Bridging, ISDN, PPP, IPX, and AppleTalk)

i For IP sebset (SNMP, IP, Bridging, WAN, Remote Node, and Terminal Services)

n For IPX support

q For asynchronous support

t For Telco return (12.0)

y For reduced IP (SNMP, IP RIP/IGRP/EIGRP, Bridging, ISDN, and PPP) (c1003 or c1004)

z For managed modems

40 For 40 bit encryption

50 For 50 bit encryption



3. The ww is for the format (where the IOS file runs in the router)

f For flash

m For RAM

r For ROM

l For the image will be relocated at run time

The file might also be compressed. The following letters denote the compression type,

z For zip compression

x For mzip compression

w For “STAC” compression



aaa-bb represent the version of the IOS. It is usually read like this “Version aa.a(bb)”. The last part of the IOS file name might contain letters like T (new feature release identifier), S (individual release number), or XR (modular packages).