Things to keep in mind when upgrading Cisco FUS (Field Upgrade Software) for a Wireless LAN Controller

What is a FUS or Field Upgrade Software?  Do I need it?  And what happens if I don’t have it installed.

“Cisco Wireless LAN Controller (WLC) Field Upgrade Software (FUS) is a special AES package that performs various system-related component upgrades. We recommend that you install the FUS image to upgrade components such as the bootloader, field recovery image, FPGA/MCU, and other firmware to their latest respective versions.” From the release notes of FUS 1.9.0.0   http://www.cisco.com/c/en/us/td/docs/wireless/controller/release/notes/fus_rn_OL-31390-01.html

Here are my notes from the Field that I think you will find very helpful.

Lets get started…

1)      Plan for a downtime window to avoid calls to the help desk that the wireless is down.

2)      Prepare your controllers by backing up the configuration.

3)      Make sure you have the software and FUS you need before arriving on site.  If deploying remotely– plan ahead and setup a local TFTP/FTP server for file transfers and place the software on a server local to the site to avoid firewalls and slow transfer speeds.

4)      If possible be ONSITE physically to monitor the device(s) Or at least have a local out of band terminal attached to console port.

5)      Attach a Serial console cable NOT mini USB to the Controller prior to FUS 1.7.0.0

6)      Large Sites that are High Touch Five Nines 99999.% Work in pairs to upgrade and monitor the controllers and check the configuration and test after reboot.  However if this is an old hat for you then by all means do it by yourself.

7)      Log your session and watch the output from the WLC Console session when upgrading the FUS code to check for anomalies since the FUS will reload a controller twice.

8)      Know what you have before you start.  Preform a show sysinfo at the command line or Monitor=Summary page of the controller.  For controllers that do not have a FUS applied e.g. older Factory Fresh WLC’s will show Field Recover Image Version 6.0.182.0.  This means that the controller most likely came from the factory with older controller software.  Don’t worry this is all good.

Example 1 (Cisco Controller) >Show Sysinfo

Manufacturer’s Name………………………… Cisco Systems Inc.
Product Name…………………………………….Cisco Controller
Product Version………………………………….7.2.111.3
Bootloader Version……………………………..1.0.1
Field Recovery Image Version………………6.0.182.0
Firmware Version……………………………….FPGA 1.3, Env 1.6, USB console 1.27

With only the initial release FUS image version 1.6.0, you will need to plan for more time as you may need to do multiple upgrade steps as you should go from one FUS to the next.  The reason I stress this is if you need to move to a particular release because you are waiting for other controllers in the domain to either be phased out (e.g. Cisco 26xx/44xx/WiSM1. Its entirely possible that you may have to sit on a older release code for the time being.  I know I will get a lot of questions on this and I know Cisco officially does say you can go directly from base FUS in the example to the latest and that may work—- but here is my two bits from field experience.

“In some cases for more complex sites,  you may have for example: a foreign controller(s) with software WLC code 7.0.235.0 on a 4400 platform mixed with WLC 5508’s with mixed code 7.2.x and 7.4.0.x in the same site.   Along with Guest Anchors that are 4400 or WiSM1’s   Ideally this is not the best practice or design,  however I run into this more often then I want.

So we all know that Guest Anchors should be on a level or higher code revision then there foreign controllers when in these mixed environments to support the above.  I have seen it many times where the Guest Anchor is older and the Foreign is newer in code release and this almost always results in crapy user experience between them.   You generally see this on WPA2/webAuth and sometimes just webAuth along with Mobility time outs between the controllers.   This brings me to FUS versions  its best to have these FUS versions running on the following codes if you are running these deployments.  Now there is nothing stoping you from having the latest FUS update but realize that they were developed in conduction with the WLC code revisions.  Are you confused and have I made this over complicated?”
Field Upgradable Software Version History to date.

1. Cisco WiSM2
   AIR-WISM2-K9-1-7-0-0-FUS.aes  = Field Recovery Image Version 7.0.112.21 Release Notes
   AIR-WISM2-K9-1-9-0-0-FUS.aes  = Field Recovery Image Version 7.6.101.1 Release Notes
2. Cisco 5500 Series
   AIR-CT5500-K9-1-7-0-0-FUS.aes  = Field Recovery Image Version 7.0.112.21 Release Notes
   AIR-CT5500-K9-1-9-0-0-FUS.aes  = Field Recovery Image Version 7.6.101.1   Release Notes
3. Cisco 2500 Series
   AIR-CT2500-K9-1-8-0-0-FUS.aes = Field Recovery Image Version 7.4.1.57 Release Notes
   AIR-CT2500-K9-1-9-0-0-FUS.aes = Field Recovery Image Version 7.6.101.1 Release Notes

WLC Code and FUS Versions

1. FUS  Base code Factory 6.0.182.0 WLC Codes Ranges 6.x.0 — 7.0.230.
2. FUS  1.7.0.0 WLC Code Ranges 7.2.235 — 7.3.112.0.
3. FUS 1.9.0.0 WLC Code Range 7.3.112.0 — 7.6.120.0
4. Future FUS x.x.x  WLC Code Ranges 8.x.x  Can’t comment. Will repost when more info is publicly available.

9)   What to expect at then end of each FUS upgrade.

1. Base Field Recovery Image Version (Factory)
   Manufacturer’s Name………………………… Cisco Systems Inc.
   Product Name…………………………………….Cisco Controller
   Product Version………………………………….7.2.111.3
   Bootloader Version……………………………..1.0.1
   Field Recovery Image Version………………6.0.182.0
   Firmware Version……………………………….FPGA 1.3, Env 1.6, USB console 1.27
2. AIR-CTXX00-K9-1-7-0-0-FUS.aes  = Field Recovery Image Version 7.0.112.21 [7.4.1.57 {WLC 2500}]
   Manufacturer’s Name………………………… Cisco Systems Inc.
   Product Name…………………………………….Cisco Controller
   Product Version………………………………….7.3.112.0
   Bootloader Version……………………………..1.0.16
   Field Recovery Image Version………………7.0.112.21
   Firmware Version……………………………….FPGA 1.7, Env 1.8, USB console 2.2
3. AIR-CTXX00-K9-1-9-0-0-FUS.aes  = Field Recovery Image Version 7.6.101.1
   Manufacturer’s Name………………………… Cisco Systems Inc.
   Product Name…………………………………….Cisco Controller
   Product Version………………………………….7.4.121.0
   Bootloader Version……………………………..1.0.20
   Field Recovery Image Version………………7.6.101.1
   Firmware Version……………………………….FPGA 1.7, Env 1.8, USB console 2.2

10)  Upgrading the Field Upgrade Software is done in the same manner as upgrading the WLC software code via the Commands=Download File Controller or the CLI (command line)

ONE CONTROLLER AT A TIME

1. DO NOT upgrade two controllers in the same site at the same time. Test your first controller before repeating the process to a secondary controller.  You may need a back out plan and a secondary controller might be a good insurance policy.  Also this can help in speeding up the downtime.
2. Also the backup software for a 7.4.121.0 controller can be and should be 7.3.112.0 until you move to 7.6.120.0 or 8.0 then 7.4.121.0 will be the SAFE Harbor backup.  There are other reasons for this that will require another post,  but if you dig through the release notes you will find out why you should have a good backup software to both support your Access Points and certain feature sets that may or may not work when falling back to an earlier software revision for what ever reason.(Cisco Controller) >show boot
   Primary Boot Image…………………………. 7.6.120.0 (default) (active)
   Backup Boot Image………………………….. 7.4.121.0

 

UPGRADE TIMES

Upgrade times are lengthy.  FUS times are at least 40min for 1.7.0.0 and 45 min for 1.9.0.0.  This does not take into account the load times of the FUS or software being transferred and loaded and reboot times.  In a site with two controllers plan for 5 hours (includes site walk through testing of Access Points).  In some cases you might encounter an older access point that did not or will not upgrade to a new version or is stuck.  Keep in mind that this is a very rare occurrence and I have come across it twice, with both 1131 and 1142’s (AP lights up and beacons but nobody is home).

Software upgrades will be time consuming on older software platforms.  5 hours?  Well yes,  remember that when you are upgrading multiple controllers FUS and Software code.  This means that you should plan accordingly and provide an outage window so you can back out if needed to a earlier code release if needed ( but rarely ever seen).  Controllers AP software updates can be time consuming as when dealing with 300+ AP’s  at a site.

Here is a quote from the release notes

When you upgrade the Cisco WLC to an intermediate software release, you must wait until all of the access points that are associated with the Cisco WLC are upgraded to the intermediate release before you install the latest Cisco WLC software. In large networks, it can take some time to download the software on each access point.

 

Unsure?
If in doubt and are not comfortable in deploying updates,  ask someone that is well versed in Cisco Wireless or your friendly Cisco Mobility Partner

 

Feb 10th, 2015.  Updated Code Table Snapshot from the updated Release notes.

 

This post will be ongoing as new versions are announced

Comments Always Welcome!!!!

–WirelessStew

 

Thanks to Mr. Clements and Mr. Chubb for the inspiration of this blog

Additional References on same topic from Fellow Wireless Field Day delegate  craig schnarrs  http://thewifiguy.net/2014/06/15/whats-all-the-fus-about/