This article explains you how to upgrade the IOS version of your Cisco Switch or Router in 9 steps. Please note that the steps given below will be similar to both switches and routers. However this examples shows how to upgrade ios image on a Cisco 3750 switch.
- Verify the Current IOS Version
- Get the IOS Image
- Get the TFTP Server Application
- Take note of the current version IOS
- Copy the new IOS image to the switch
- Verify the new IOS image checksum
- Modify Switch Boot path-list
- Save Config and Restart the Switch
- Final Verification after IOS Upgrade
1. Verify Current IOS Version
After you login, go to enable mode, by entering the enable password. This example uses 3 Cisco catalyst 3750 switches configured in stack mode as shown below. So, while upgrading you should upgrade the image on both the flash cards.
SW80FRHAG18X#show switch Switch/Stack Mac Address : 0023.5e9x.6400 H/W Current Switch# Role Mac Address Priority Version State ---------------------------------------------------------- *1 Master 0023.5e9b.6400 15 0 Ready 2 Member 0023.33da.b700 10 0 Ready 3 Member 0027.0c9a.c400 5 0 Ready
If you have only one cisco catalyst switch (non stack mode), follow all the steps mentioned in this document, but you’ll be doing it only on one flash card.
First, verify the content of the flash cards, using “dir flash1:” command.
SW80FRHAG18X#dir flash1: Directory of flash:/ 2 -rwx 736 Oct 18 2012 15:03:35 +02:00 vlan.dat.renamed 3 -rwx 3144 Aug 17 2012 16:06:19 +02:00 vlan.dat 4 -rwx 5 Aug 17 2012 16:44:23 +02:00 private-config.text 5 drwx 192 Mar 1 1993 01:06:32 +01:00 c3750-ipbase-mz.122-35.SE5 509 -rwx 5 Oct 18 2012 15:03:39 +02:00 private-config.text.renamed 510 -rwx 19691 Oct 18 2012 15:03:39 +02:00 config.text.renamed 512 -rwx 19806 Aug 17 2012 16:44:23 +02:00 config.text 15998976 bytes total (6325760 bytes free) SW80FRHAG18X#dir flash2: Directory of flash2:/ 2 -rwx 3144 Mar 1 1993 01:00:58 +01:00 vlan.dat 3 -rwx 19806 Aug 17 2012 16:44:24 +02:00 config.text 4 -rwx 5 Aug 17 2012 16:44:24 +02:00 private-config.text 5 drwx 192 Mar 1 1993 01:06:30 +01:00 c3750-ipbase-mz.122-35.SE5 15998976 bytes total (6347264 bytes free) SW80FRHAG18X#dir flash3: Directory of flash3:/ 2 -rwx 3144 Mar 1 1993 01:00:57 +01:00 vlan.dat 3 -rwx 19806 Aug 17 2012 16:44:23 +02:00 config.text 4 -rwx 5 Aug 17 2012 16:44:23 +02:00 private-config.text 5 drwx 192 Mar 1 1993 01:07:25 +01:00 c3750-ipbase-mz.122-35.SE5 15998976 bytes total (6347264 bytes free)
As you see above, both the flash cards contains the current IOS image file, which is version “122.35.SE5”
Verify what version of IOS image your switch is currently running. Most likely this will be same as the current IOS image file that you see in your flash card. As you see below, it is using “12.3(35)SE5”
# show version Switch Ports Model SW Version SW Image ------ ----- ----- ---------- ---------- * 1 26 WS-C3750-24TS 12.2(35)SE5 C3750-IPBASE-M 2 52 WS-C3750-48TS 12.2(35)SE5 C3750-IPBASE-M 3 26 WS-C3750-24TS 12.2(35)SE5 C3750-IPBASE-M
2. Get the IOS image
The first thing you need to do is to logon to the Cisco Website with you cisco-id account and visit this link: https://software.cisco.com/download/home/282526529/type/280805680/release/12.2.55-SE12
It is from there that you would be able to download the latest version of IOS version for the Cisco 3750, the 15.0.2.SE11
Download the latest IOS image for your cisco website
Go to cisco.com -> IOS Software -> Select your Siwtch (for example: Cisco Catalyst Switch 3750G-24T) -> Click on “Download IP BASE” -> Select the latest version that you want to download (for example: 12-2.55.SE1).
While you are on this download page, copy/paste the MD5 given to your system. After we download the IOS image and move it to the switch, we’ll verify the MD5 checksum before installing the image.
Download the file to a location of your choice, or a computer where you can install the TFTP server program
3. Get the TFTP server application
Next, visit this site (http://tftpd32.jounin.net/tftpd32_download.html) and download the TFTP64 application, install it on your machine and configure it so that it points to the folder where you have the IOS image previously downloaded. In my example below I’m pointing to the folder
4. Delete Old IOS Software Image from Flash
Since we’ll be downloading the new ISO image and moving it to the flash card, we need some space. So, delete the current old image from the flash card.
# delete /f /r flash1:c3750-ipbase-mz.122-35.SE5 # delete /f /r flash2:c3750-ipbase-mz.122-35.SE5 # delete /f /r flash3:c3750-ipbase-mz.122-35.SE5
In the above delete command, /f stands for force, and /r stands for recurssive.
On a side note, you should be using some software to monitor your switch status. If you are not doing it install Nagios, and monitor your switches.
5. Copy the new IOS image to the switch
To transfer the IOS image from your laptop to Cisco Switch, you should run a TFTPserver on your laptop (or on the system where you’ve downloaded the IOS image).
If you are running a TFTPserver on your laptop, and connected to the switch using a console cable, assign a ip-address to your laptop, and put your laptop on the same network as the switch.
Copy the ISO image to the flash as shown below using the “copy command”. This will ask you to enter the address of the remote host (which is your laptop in this case), and the source filename that needs to be transferred (which is the ISO image you downloaded from cisco website).
Run this command:
#copy tftp flash:
SW80FRHAG18X#copy tftp flash1: Address or name of remote host [10.57.x.122]? Source filename [c3750-ipbase-mz.122-35.SE5]? c3750-ipbasek9-mz.122-55.SE12.bin Destination filename [c3750-ipbasek9-mz.122-55.SE12.bin]? Accessing tftp://10.57.4.122/c3750-ipbasek9-mz.122-55.SE12.bin... Loading c3750-ipbasek9-mz.122-55.SE12.bin from 10.57.4.122 (via Vlan1): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!... [OK - 12111413 bytes]
Once you’ve copied it, make sure the file is there on the flash card.
SW80FRHAG18X#dir flash1: Directory of flash:/ 2 -rwx 736 Oct 18 2018 15:03:35 +02:00 vlan.dat.renamed 3 -rwx 3144 Aug 17 2022 16:06:19 +02:00 vlan.dat 4 -rwx 12111413 Aug 18 2022 10:16:05 +02:00 c3750-ipbasek9-mz.122-55.SE12.bin 509 -rwx 5 Oct 18 2018 15:03:39 +02:00 private-config.text.renamed 510 -rwx 19691 Oct 18 2018 15:03:39 +02:00 config.text.renamed 511 -rwx 19667 Mar 1 1993 01:16:44 +01:00 config.text 512 -rwx 5 Mar 1 1993 01:16:44 +01:00 private-config.text 15998976 bytes total (3840512 bytes free)
Just to make sure nothing went wrong during the copy, do a MD5 check-sum on this, and compare with the MD5 that you noted down from cisco website while downloading the IOS image. To create MD5 checksum of a file in Cisco catalyst switch, use the “verify” command as shown below.
# verify /md5 flash1:c3750-ipbasek9-mz.122-55.SE12.bin
If you are running 3 switches in stack configuration, do the same on the second and third flash card.
# copy tftp flash2: # dir flash2: # verify /md5 flash2:c3750-ipbasek9-mz.122-55.SE12.bin *** # copy tftp flash3: # dir flash3: # verify /md5 flash2:c3750-ipbasek9-mz.122-55.SE12.bin
And when prompted, enter the IP address of the machine where the TFTP server is running, and paste the name of the new IOS image (that previously you would have copied to the clipboard), then wait for the file to be copied across
6. Verify the new IOS image checksum
Visit the TFTP application, and ensure the copy process has been done successful and without errors, once it reaches 100% check the log tab to see if there is any errors
In addition, run this command on the switch to double-check that the new image has been copied correctly
#verify /md5 flash:c3750-ipbasek9-mz.122-55.SE12.bin
If at some point the above command pauses, the image has NOT been copied correctly, and you need to do it again. Use CRTL+Z to come out, then use this command to delete the corrupted image and, guess what…try it again!
7. Modify Switch Boot path-list
Now it is time to tell switch cisco to use the new ISO image to boot from. Before changing the boot information, verify the current configuration, and change it using the “boot system” command as shown below.
# show boot # config t # boot system switch all flash:c3750-ipbasek9-mz.122-55.SE12.bin
8. Save Config and Restart the Switch
Verify the current boot information, save the current configuration, and reboot the cisco switch as shown below.
# show boot # write mem # reload
9. Final Verification after IOS Upgrade
Finally verify the current IOS version of the switch, after the upgrade, it should display the new version as shown below.
# show version Switch Ports Model SW Version SW Image ------ ----- ----- ---------- ---------- * 1 26 WS-C3750-24TS 12.2(55)SE12 C3750-IPBASEK9-M 2 52 WS-C3750-48TS 12.2(55)SE12 C3750-IPBASEK9-M 3 26 WS-C3750-24TS 12.2(55)SE12 C3750-IPBASEK9-M
Make sure to verify your interface and vlan status, to make sure everything is running properly without any issues.
Thank you for reading, and I hope this guide has helped you. You may drop your comments below
Paris, 15 December 2012