Upgrade Cisco IOS in a Router or a Switch

upgrading IOS on Cisco routers and switches is hightly recommendable because of the following reasons

Patch critical vulnerabilities: Just like any other network device or application, Cisco routers and switches are also prone to security holes. And because routers and switches are critical to network infrastructure, you should plug these security holes as soon as possible.

Incorporate new features: Unless an update is simply a bug fix, every new release of the Cisco IOS includes new features. Upgrading your routers and switches in a timely manner means you’ll have more features to potentially make your job easier.

Stay current: “Staying current” with the latest IOS may sound like a flimsy justification to upgrade, especially when you consider your daily task list. However, when you consider the many different tools that communicate with the router’s IOS, staying current can take on a new importance. For example, if you’re using a SNMP network management tool, it may require your router to run a certain version of the IOS.

Follow this procedure if you want to upgrade cisco IOS

NOTE :- Before doing any upgrades plesae take a complete backup of your cisco device configuration for safer side

Download the Correct version of Cisco IOS for you from here http://www.cisco.com/tacpage/sw-center/index.shtml

Write Unsaved configurations

ciscorouter# write memory
Building configuration…

Check space on Flash Memory

ciscorouter# show flash

Make sure you have the space left on your cisco device.

Backup Startup Configuration

Setup a TFTP server in the same IP range as the Cisco device to backup the configs, IOS image and also for later to upload the new IOS image.

testrouter# copy startup-config tftp
Address or name of remote host []?
Destination filename [startup-config]?
1278 bytes c opied in 0.100 secs

Backup Current IOS Image

testrouter# copy flash: tftp:
Source filename []? xxxxx-xx-xx.121-x.XB
Address or name of remote host []?
Destination filename [xxxxx-xx-xx.121-x.XB]?

Now, Load the new IOS image from the TFTP onto the flash

ciscorouter#copy tftp: flash:
Address or name of remote host []?
Source filename []? c3560-ipbasek9-mz.122-40.SE.bin
Destination filename [c3560-ipbasek9-mz.122-40.SE.bin]?
Accessing tftp://…
Loading c3560-ipbasek9-mz.122-40.SE.bin from (via Vlan1): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[OK – 8295106 bytes]

8295106 bytes copied in 124.571 secs (66589 bytes/sec)

Now you need to make sure you are booting with the correct version of IOS image for this you need to use the following command to set.

testrouter(config)#boot system flash:/c3560-ipbasek9-mz.122-40.SE.bin

Now you need to reload the Cisco Router

testrouter# reload

After rebooting cisco device with the new Cisco IOS image you need to make sure this use the following command

testrouter# sh ver

That’s it now we are using the latest IOS on your cisco device

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10 thoughts on “Upgrade Cisco IOS in a Router or a Switch

  1. Hi, the procedure is great, I have done it.
    But to “Downgrade”, is the same procedure???. For instance, I have a Switch 4510, I have found the procedure to upgrade the ios, but I’ll need to downgrade it.

    I would thank and rapid answer.

    Thank you

  2. @Gabriel Garcia

    It is the same to downgrade except for one thing
    You have to run the command erase flash: to remove the current IOS before loading the new/old one.

    What kind of problems are you having with the newer IOS that would make you want to downgrade?


  3. Yes I got my switch ios upgraded.

    Thanks a lot.

    Virender S. Negi

  4. The steps are really appreciable. After upgraded I have few more things that I’m not satisfied:
    product:catalyst cisco 3560 series
    IOS ver before : 12.2(44)SE5
    IOS ver after: 12.2.(55)SE
    when I access the new upgraded IOS from the browser, I didnt find the IOS upgrade options, details of switch like its current IOS, model no. and etc that used to diplay in previous IOS..
    So, for the basic and important features like I have mentioned above in the cisco switch new latest upgraded one is not user frendly.
    So my concerns:
    1. To find the old versions features like I have mentioned above do I need to downgrade the IOS?
    2. To downgrade from CLI you have mentioned to erase flash first. Erase flash means delete all the current configurations. Is there any way to downgrade the IOS and not loosing of current configurations?


  5. @shrijan: The reason you need to erase the flash is that it typically isn’t large enough to hold two system images.

  6. use command
    to list flash: -content.
    If there is enough of room for two IOS images, then you can, by all means have two IOS images running on same switch.

    If you want to go for the older IOS image use boot system command to do that. First list your running boot settings
    switch#sh boot
    BOOT path-list : flash:c2960-lanbasek9-mz.122-53.SE2/c2960-lanbasek9-mz.122-53.SE2.bin

    then you can change it to different image and keep the current as backup..

    switch#configure terminal
    switch(config)#boot system flash:c2960-lanbase-mz.122-35.SE2/c2960-lanbase-mz.122-35.SE2.bin;flash:c2960-lanbasek9-mz.122-53.SE2/c2960-lanbasek9-mz.122-53.SE2.bin

    as an example.. Assuming that you have two different directories in flash: called:

    and that those both house refered ios image file (.bin)
    c2960-lanbase-mz.122-35.SE2.bin @ flash:/c2960-lanbase-mz.122-35.SE2

    Why would you not use Cisco Network Assistant to upgrade IOS? It makes it easy as what..

  7. Give me the procedure of IOS upgrade with ftp in connected by a PC?

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