Information About Image Download
Software updates ensure that all the access points in the Cisco Embedded Wireless Controller network are running the latest software. The software update or image download can be performed using both the GUI and the CLI.
A typical Cisco Embedded Wireless Controller network contains the following components:
Cisco Catalyst APs acting as controller (embedded wireless controller)
Cisco Embedded Wireless Controller-capable APs (Other Cisco Catalyst series APs that participate in the Virtual Router Redundancy Protocol (VRRP)-based election process)
Subordinate APs (Cisco Catalyst Series or Cisco Aironet Series Wave 2 APs)
External TFTP and SFTP server.
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Updates to the AP Image Predownload Status (GUI)
From Cisco IOS XE Amsterdam, Release 17.3.1 onwards, during an access point (AP) image download, the Cisco Embedded Wireless Controller on Catalyst Access Points calculates the current percentage of the download and the estimated completion time of the download. (You can view these values in the CLI output by running the show wireless ewc-ap ap image predownload status command.)
To access the Software Upgrage window, from the Cisco Embedded Wireless Controller on Catalyst Access Points home page, choose Administration > Software Management > Software Upgrade.
The Software Update Status section in the GUI displays the update status bar that shows the progress of a software update, such as, Initiate, Controller Image Download, AP Image Download, Network Upgrade, Activate, and Reload.
To view the logs, click the Show Install Logs link.
The Status field displays the current status of the upgrade and indicates further action, if any, that you should perform.
The other details displayed in the window are - Total Number of APs, Initiated, Predownloading AP Image, Predownloading Controller Image, Completed Predownloading AP Image, Completed Predownloading Controller Image, Failed to Predownload AP Image, Failed to Predownload Controller Image.
The currently active AP, the AP on standby, and the preferred active AP are also displayed.
Image Download Scenarios
In a Cisco Embedded Wireless Controller network, image download from the embedded wireless controller to the subordinate AP takes place in the following scenarios:
During AP join
During network software upgrade (pre-download)
Image Download During AP Join
APs with older software trying to join the Cisco Embedded Wireless Controller network are automatically upgraded to match the latest software version on the embedded wireless controller. The embedded wireless controller compares the software version on the new AP with that on itself. If there is a mismatch, the AP requests the controller for a software upgrade and image download is triggered. The embedded wireless controller facilitates the transfer of the latest software from an external TFTP server or SFTP server, to the new AP.
Depending on the new AP joining the network, there are two image downloads that take place:
AP software image download: This applies to all new APs joining the Cisco Embedded Wireless Controller.
Controller software image download: This applies only to Cisco Catalyst series APs, capable of becoming a controller, trying to join the Cisco Embedded Wireless Controller network.
AP Software Image Download
Any Cisco Catalyst Series AP or Cisco Aironet Series Wave 2 AP can only join an embedded wireless controller if its AP software image version matches that of the controller.
During the AP join process, the embedded wireless controller first checks the AP software image version on the new AP and if it does not match what is on the controller, the latest AP software is downloaded from the controller to the new AP. Once the AP software image on the new AP is upgraded to match the version that is on the embedded wireless controller in the network, the new AP reloads. Once the new AP is back up with the upgraded AP software image, it joins the embedded wireless controller.
Controller Software Image Download
If the new AP joining the network is a CiscoCatalyst Series AP capable of becoming an embedded wireless controller, first the controller checks the AP software image on the new AP and if outdated, it is upgraded to match the AP software version on the controller. The AP then reloads with the new AP software image and joins theembedded wireless controller in the network.
Next, the embedded wireless controller does a similar check to compare the controller software version on the embedded wireless controller-capable AP. Similar to the AP software upgrade, if there is a mismatch, the controller software on this CiscoCatalyst Series AP is also upgraded to the latest version on the embedded wireless controller. The AP reloads again, this time with the upgraded controller software image.
Efficient AP Join
If the Cisco Embedded Wireless Controllerr network contains an AP of the same image type as the newly joining AP, then the new AP downloads the AP software image from this AP. For example, if a CiscoCatalyst 9130AX Series AP is newly joining the Cisco Embedded Wireless Controller network and another CiscoCatalyst 9130AX Series AP already exists in the network, then the new AP gets its AP software image from the already joined AP.
This method, known as efficient AP join, enables homogenous APs to get the software locally (within the Cisco Embedded Wireless Controller network) rather than downloading it from an external server. This improves software download efficiency.
The first AP of a series that joins the network and downloads the software from the embedded wireless controller is called a primary image. The other APs of the same series are known as image subordinates.
Network Software Upgrade (Pre-Download)
In the pre-download scenario, image download in the Cisco Embedded Wireless Controller network occurs to upgrade the software on all the APs from one software version to another. However, these APs continue to serve existing as well as new clients and there is no network disruption.
For pre-download, all the APs should be connected to the embedded wireless controller in a stable join state. Once image download is initiated during pre-download, new APs are not allowed to join the embedded wireless controller.
Efficient AP Upgrade
In this method, the first AP of an AP series to get the image from the embedded wireless controller becomes the primary image. The remaining APs of the same AP series, the image subordinates, then download the software image locally from this primary image. This method is also known as efficient AP upgrade.
Methods Supported for Image Download
In a Cisco Embedded Wireless Controller network, there are four ways in which the software image can be downloaded from the embedded wireless controller. These methods are based on the location from where the controller transfers the software image to the subordinate AP:
From an external TFTP server
From an external SFTP server
From the desktop (via HTTP)
TFTP Image Download Method
In the TFTP method, the AP and controller software images are stored on a TFTP server. To download the software images from the TFTP server, you need to specify the IP address of the TFTP server and the path to the software image bundle on the TFTP server.
The TFTP image download method can be triggered using both the GUI and CLI.
SFTP Image Download Method
In the SFTP method, the AP and controller software images are stored on an SFTP server. To download the software images from the SFTP server, in addition to the IP address of the SFTP server and the software image bundle path, you need to specify the SFTP server credentials.
The SFTP image download method also can be triggered using both the GUI and CLI.
Desktop (HTTP) Image Download Method
Image download through desktop (HTTP) is applicable only in the network software upgrade (pre-download) scenario.
For the desktop (HTTP) method, download the software image bundle for the Cisco Embedded Wireless Controller to your computer or laptop desktop. This downloaded bundle contains the AP and controller software images which need to be extracted to the computer or laptop desktop before they can be uploaded to the embedded wireless controller.
Note that the desktop (HTTP) method works only for a homogenous network. A homogenous Cisco Embedded Wireless Controller network is one which contains APs that have the same AP software image type. For example, the Cisco Catalyst 9115AX series AP and the Cisco Catalyst 9120AX series AP use the ap1g7 AP software image file. So, the Cisco Embedded Wireless Controller network in this example containing Cisco Catalyst 9115AX series and 9120AX series APs is a homogenous network.
The embedded wireless controller CLI can only be used to set the mode for image download as desktop (HTTP). The Cisco Embedded Wireless Controller GUI has to be used to configure and trigger network software upgrade (pre-download) using the desktop (HTTP) image download method.