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Community Member

upgrade questions

There are some points I want to receive confirmation about

From the config guide

Step 4

Disable the controller 802.11a and 802.11b/g networks.

Step 5

For Cisco WiSMs, shut down the controller port channel on the Catalyst 6500 Series switch to allow the controller to reboot before the access points start downloading the software.

Step 6

Disable any WLANs on the controller.

Question 1

I assume step 4 and 6 are recommend when doing during business hours?

Question 2

Assume business hours, is step 6 only sufficient? Why should I disable abg networks?

Question 3

Normally the ap's upgrade when they rediscover the WLC (and when the WLC has been rebooted = running the new software). What about step 5 then?? What's different with WISM?

About predownloading image to APs

From the config guide:

Question 4

Are we talking about the controller or the access points? I suppose the access points

Thus for predownloading

Interchange image (current software moved to backup)

Download Primary

I don't see why... If you do download backup and the ap reboots, it could use the old primary image.

What about the WISM, is this possible (see step 5 and question 3)

I wish I had material to play with and test it myself ;-)

Before you enter the predownload command, you should change the active controller boot image to the backup image. This step ensures that if the controller reboots for some reason, it comes back up with the earlier running image, not the partially downloaded upgrade image.

Cisco Employee

Re: upgrade questions

Hi Rik,

Question 1 : I guess you did a typo. This is recommended to do outside of business hours . Anyway a WLC upgrade will bring the wireless network down for some minutes :-)

Question 2 : It is a decent and correct way to shut down the clients rather than starting the code upgrade and rebooting WLC all of a sudden. Whether you disable a/b networks before upgrade or not, the downtime will stay the same.

Question 3: because you have 2 WLCs inside a wism, after rebooting one, the APs might be joining the second one already. And a WLC refuses to reboot when an AP is trying to join. So disabling the portchannel prevents this proble, and lets you reboot quietly

Question 4 :

The idea is the following.

When you upgrade the WLC and don't reboot it yet, it still runs the old software until reboot. Automatically the WLC is set to be on the new software at next reboot.

Preloading the image to APs means that you send them their future AP image already (to minimize downtime when you reboot everything). If you are preloading the image to lots of APs, it might take some time. The advice just tells you that if your WLC reboots all of a sudden, it will boot on the new image. And if you are doing preloading it means you are "preparing" for upgrade and not in the maintenance window yet. So for safety you can set the next boot image to be the "old" software so that you only move to new software when you decide it (could be 2 days later)



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Community Member

Re: upgrade questions

Thanks you very much for your input.

Question 2 : It is a decent and correct way to shut down the clients rather than starting the code upgrade and rebooting WLC all of a sudden. Whether you disable a/b networks before upgrade or not, the downtime will stay the same.

But only disabling the WLAN is the same? As there is no WLAN to connect to or what is the added value of also bringing down the radios?

About predownloading,

You have the primary image and the backup image >

The idea is to move the primary active image to the backup image. (>first action = swap)

Download the new code to the primary image?

In case of interruption (power outage, ...) the AP will boot, notice that the primary image is not valid and thus using the backup image?

But if you download the new code to the backup 'partition' it's the same if a failure (power,...) occurs because the primary image is still untouched?

Cisco Employee

Re: upgrade questions

About question 2 : disabling WLANs means clients disconnected but radios not especially down. Now if all WLANs are disabled, I don't see the value of also disabling the networks :-)

About the predownloading, there is no "primary" and "backup" partitions. There are 2 software images. And you can select which one will be active at next reboot. So when you download a code to WLC, it is automatically setting the non-active partition (Where code was downloaded) as next active partition on reboot.



Re: upgrade questions


never mind

Community Member

Re: upgrade questions

I'm still not at the point I wanted to be.
So you upgrade the WLC and don't reboot yet and then you can prepare the aps by already downloading the new image to the AP.

Under wireless>All access points > global configurartion

at the bottom you've:

perform a primary image pre-download

perform a backup image pre-download

swap image

what is the difference between perform a primary/backup image pre download.

I think, whatever you chose, if something happens, powerloss, the active image is still on the ap?

So about the portchannel - wism.

If you for example have 2 Wism_4 coontrollers  (W1_c1 W1_c2) (W2_c1 W2_c2) where ap's are divided in 2 groups

group1 (AP1,ap11,..)

W1_c1 primary W2_c1 secondary


W1_c2 primary W2_c2 secondary

>all aps are on wism1


1)tftp new software to ALL 4 controllers

2) reboot W2 (c1 +c2)

3) wait until W2 is up

4) all aps are connected to W1

5) reboot W1

> download software to aps will be distributed over all controllers?

Cisco Employee

Re: upgrade questions

Your sequence is not optimal.

If you reboot Wism 2, wait for all aps to join Wism1 and then reboot Wism 1, you have 2 downtimes.

If you reboot everything at the same time, you will have the minimal downtime.

Don't forget that an AP changing controller is not instantaneous and does disconnect clients.



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