FlexConnect AP Upgrades for FlexConnect APs
Information About FlexConnect AP Upgrades
Normally, when upgrading the image of an AP, you can use the pre-image download feature to reduce the amount of time the AP is unavailable to serve clients. However, it also increases the downtime because the access point cannot serve clients during an upgrade. The Pre-image download feature can be used to reduce this downtime. However, in the case of a branch office set up, the upgrade images are still downloaded to each access point over the WAN link, which has a higher latency.
A more efficient way is to use the FlexConnect AP Upgrade feature. When this feature is enabled, one access point of each model in the local network first downloads the upgrade image over the WAN link. It works similarly to the master-slave or client-server model. This access point then becomes the master for the remaining access point of the similar model. The remaining access points then download the upgrade image from the master access point using the pre-image download feature over the local network, which reduces the WAN latency.
Restrictions for FlexConnect AP Upgrades for FlexConnect Access Points
- The primary and secondary controllers in the network must have the same set of primary and backup images.
- If you configured a FlexConnect group, all access points in that group must be within the same subnet or must be accessible through NAT.
- A FlexConnect group can have a maximum of 100 APs on Cisco 7510 WLC, and 25 APs on Cisco 5508 WLC.
- A FlexConnect group can have one master AP per AP model. If a master AP is not selected manually, the AP that has the least MAC address value is automatically chosen as the master AP for that model.
- A maximum of 3 slave APs of
the same model can download the image from their master AP (a maximum of 3
TFTP connections can serve at a time). The rest of the slave APs use the
random back-off timer to retry for the master AP to download the image.
The random back-off(随机回退) value is more than 100 seconds. After a
slave AP downloads the image, the AP informs the Cisco WLC about the
completion of the download. After random back-off, the waiting slave AP
can occupy the empty TFTP slot at the master AP.
If a slave AP fails to download the image from its master AP even after the slave retry count that you have configured is exhausted, the slave AP reaches out to the Cisco WLC to fetch the new image. - This feature works only with CAPWAP APs.
- This feature does not work if a master AP is connected over CAPWAP6.
- If you upgrade from a release that is prior to Release 7.5 directly to Release 7.6.X or a later release, the predownload process on Cisco AP2600 and AP3600 fails. After the Cisco WLC is upgraded to Release 7.6.X or a later release, the new image is loaded on Cisco AP2600 and AP3600. After the upgrade to a Release 7.6.X image, the predownload functionality works as expected. The predownload failure is only a one-time failure.
Configuring FlexConnect AP Upgrades (GUI)
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Step 1 |
Choose Wireless > FlexConnect Groups. The FlexConnect Groups page appears.
This page lists the FlexConnect Groups configured on the controller. |
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Step 2 |
Click the Group Name link on which you want to configure the image upgrade. |
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Step 3 |
Click the Image Upgrade tab. |
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Step 4 |
Check the FlexConnect AP Upgrade check box to enable a FlexConnect AP Upgrade. |
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Step 5 |
If you enabled the FlexConnect AP upgrade in the previous step, you must enable the following parameters: |
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Step 6 |
From the AP Name drop-down list, click Add Master to add the master access point. You can manually assign master access points in the FlexConnect group by selecting the access points. |
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Step 7 |
Click Apply. |
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Step 8 |
Click FlexConnect Upgrade to upgrade. |
Configuring FlexConnect AP Upgrades (CLI)
- config flexconnect group group-name predownload {enable | disable}—Enables or disables the FlexConnect AP upgrade.
- config flexconnect group group-name predownload master ap-name—Sets the AP as the master AP for the model.
- config flexconnect group group-name predownload slave ap-name ap-name—Sets the AP as a slave AP.
- config flexconnect group group-name predownload slave retry-count max-retry-count -Sets the retry count for slave APs.
- config flexconnect group group-name predownload start {abort | primary | backup}—Initiates the image (primary or backup) download on the access points in the FlexConnect group, or aborts an image download process.
- show flexconnect group group-name—Displays the summary of the FlexConnect group configuration.
- show ap image all—Displays the details of the images on the access point.
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