Cisco IOS Version Details

Posted on 2007-08-08
Last Modified: 2013-11-05

I would like to upgrade the IOS on my 831 Ethernet router. When looking at the cisco website I am not sure which feature set I have. The available options are:


My Show Version output is as follows:

Cisco Internetwork Operating System Software
IOS (tm) C831 Software (C831-K9O3SY6-M), Version 12.2(13)ZH, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)
Synched to technology version 12.2(14.5)T
TAC Support:
Copyright (c) 1986-2003 by cisco Systems, Inc.
Compiled Thu 24-Apr-03 19:51 by ealyon
Image text-base: 0x800131E8, data-base: 0x80AC8194

ROM: System Bootstrap, Version 12.2(8r)YN, RELEASE SOFTWARE (fc1)
ROM: C831 Software (C831-K9O3SY6-M), Version 12.2(13)ZH, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)

router831 uptime is 5 weeks, 4 days, 12 hours, 48 minutes
System returned to ROM by power-on
System restarted at 07:38:28 EST Sat Jun 30 2007
System image file is "flash:c831-k9o3sy6-mz.122-13.ZH.bin"

CISCO C831 (MPC857DSL) processor (revision 0x300) with 44237K/4915K bytes of memory.
Processor board ID AMB07220L1R (1895853720), with hardware revision 0000
CPU rev number 7
Bridging software.
2 Ethernet/IEEE 802.3 interface(s)
128K bytes of non-volatile configuration memory.
24576K bytes of processor board System flash (Read/Write)
2048K bytes of processor board Web flash (Read/Write)

Configuration register is 0x2102


Would someone please advise how I can tell which feature set to use?

Thanks in advance.

Question by:amerretz
    LVL 79

    Expert Comment

    This tells you what feature sets you have
    But, Cisco has moved away from the PLUS designation in their new roadmap
    LVL 79

    Expert Comment

    What you have currently is IP/FW/PLUS 3DES

    Author Comment

    I have read the link which your sent and it explains that this new software model has not been implemented for the 800 series yet.

    Can you please explain what k903sy6 means?

    Thanks for your help.
    LVL 9

    Expert Comment


    Anything with "k9" means it's able to do encryption.
    For an 831 with 48MB flash - as you have - i'm using "c831-k9o3y6-mz.123-11.T11.bin" for my remote locations (with 48MB flash) which seems to be the latest stable version before going to 12.4, which needs 64MB flash which you dont have.
    LVL 79

    Accepted Solution

    This shows you what feature set has that in the image file name

    k9 = 3DES
    03 = FW
    s = PLUS
    y = IP

    Author Comment

    What stable IOS version would you recommend for the PLUS version which I have?

    I was thinking of upgrading to 12.3(11)YZ1 - c831-k9o3sy6-mz.12.3-11.YZ1 due to the IPV6 compatibility. This is the first time upgrading, so I am unsure.


    Expert Comment

    I'm currently running c831-k9o3sy6-mz.123-11.YZ1.bin on an 831 with 48mb/12mb and have found it to be stable.

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