IOS Image Filenames

IOS is the software that resides inside the Cisco device. You can think of IOS as the kernel or the actual operating code within your router. The IOS image has a name, which specifies the platform for which the image was built, the features it includes, and where the image is located in memory. To see the name of the image your router is running, give the command show version:

Router>show version
Cisco Internetwork Operating System Software IOS (tm)
 3600 Software (C3640-JS-M), Version 12.0(5)T1, RELEASE SOFTWARE (fc1)

In this example, C3640-JS-M is the IOS image name. The name has three parts: platform identifier , feature set, and image execution location. In this example, C3640 is the platform identifier, JS is the feature set, and M is the image execution location.

2.1.1. Platform Identifier

The platform identifier indicates the hardware for which the image was built. Table 2-1 lists the most common platform identifiers. This list is quite extensive and grows as new products are released.

Table 2-1. Common platform identifiers

Identifier	Platforms
as	Access Server 5200 series
ca	Cisco Advantage
cpa	Cisco Pro
cs	Communication Server
c800, c1000, c1005, c1600	Cisco 800, 1003, 1004, 1005, 1600
c2500	Cisco 2500-2525 series routers
c2600	Cisco 2610-2613 series routers
c2800	Catalyst 2800
c2900	Cisco 2910, 2950
c29atm	Cisco 2900 ATM
c3620, c3640, c3800	Cisco 3620, 3640, 3800
c5200, c5300	Cisco AS5200, AS5300
c4000,c4500,c4700	Cisco 4000 series routers
c5fsfc	Catalyst 5000 series
c5rsm	Catalyst 5000 RSM
c5atm	Catalyst ATM
c6400s, c6400r	Cisco 6400 NSP, Cisco 6400 NRP
c6msm	Catalyst
c7000	Cisco 7000, 7010
c7200	Cisco 7200
Igs	IGS, 2500, 3000, and 5100 series routers
gs3	AGS and AGS+ gateway routers
gs7	7000 series gateway routers
Gsr	Gigabit Switch Router (12000)
ls1010	LightStream 1010
Mc3810	Multiservice Cisco 3810
Rpm	MGX 8850
RSP	Cisco 7500 series

 

2.1.2. Feature Set

The feature set describes the options that are included in the IOS image. Table 2-2 lists the most popular feature sets. Keep in mind that features are often tied to platformsany given platform supports only some feature sets. Also, note that the feature set indicators may be combined. For example, the IOS image C3640-JS-M has the feature set JS, which combines the Enterprise Subset feature set (J) with the Source Route Switch feature set (S).

Table 2-2. Common feature sets

Feature set	Contents
A	APPN
A2	ATM
B	AppleTalk
BOOT	Boot image
C	Remote Access Server
D	Desktop subset (SNMP, IP, BRIDGING, WAN, Terminal Services, IPX, ATALK, ARAP)
D2	Desktop Plus
Dsv	Desktop/IBM
EBOOT	Ethernet boot image for MC3810
F	FRAD subset
G	ISDN subset
G2	Gatekeeper proxy, voice and video
G3	ISDN subset for c800 (IP, ISDN, Frame Relay)
I	IP subset
I2	IP subset for 3600
I3	Reduced IP subset with BGP/EGP/NHRP removed
Is	IP Plus
Is56i	IP IPSec 56
J	Enterprise subset (protocol translation)
Js40	Enterprise 40
Jsv56	Enterprise IPSec 56
Js	Enterprise Plus
Js40	Enterprise Plus 40
Js56i	Enterprise Plus IPSec 56
K	Kitchen sink
K1	Privacy key encryption (11.3 and above)
K3	Triple DES (11.3 and above)
K4	168-bit encryption with SSH
L	IpeXchange IPX, static routing, gateway
M	RMON
N	IPX
O	Firewall
O2	Firewall (3xx0)
O3	Firewall with SSH (36x0, 26x0)
P	Service provider (IP RIP/IGRP/EIGRP/OSPF/BGP CLNS ISIS/IGRP)
R	RSRB (remote source route bridging); this option can be added to other feature sets
S	Source route switch (SNMP, IP, BRIDGING, SRB)
V	VIP and dual RSP support
V2	Voice V2D
V3	Voice feature card
X	X.25 (11.1 and earlier), and on 12.0T on c800 series
X	Frame Relay in 11.2
X	H.323 Gatekeeper/Proxy for 2500, 3620, 3640, MC3810
Y	Reduced IP (SNMP, IP RIP/IGRP/EIGRP, BRIDGING, ISDN, PPP), for low-end routers
Y2	IP variant (SNMP, IP RIP/IGRP/EIGRP, WAN -X.25, OSPF, PIM)
Y3	IP/X.31
Y4	Reduced IP variant (Cable, MIBs, DHCP, EZHTTP)
Y5	Reduced IP variant (Cable, MIBs, DHCP, EZIP) for home office
Y6	Reduced IP variant (c800)

 

2.1.3. Image Execution Location

The image execution location describes where the image is to be located in the router's memory. For example, given the image name C3640-JS-M, the M indicates that the image can be stored in RAM. Table 2-3 lists the most common execution locations. Keep in mind that some of these can be combined; for example, the location LZ indicates that the image is relocatable and has been compressed.

Table 2-3. Execution locations

Flag	Location
F	Flash
M	RAM
R	ROM
L	Relocatable
C	Flash card (PCMIA)
Z,X,W	Image is compressed