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)
Step 1
|
Choose Wireless > FlexConnect
Groups.
The FlexConnect Groups page appears.
This page lists the FlexConnect Groups configured on the controller.
|
Step 2
|
Click the Group Name link on which you want to configure the image upgrade.
|
Step 3
|
Click the Image
Upgrade tab.
|
Step 4
|
Check the FlexConnect
AP Upgrade check box to enable a FlexConnect AP
Upgrade.
|
Step 5
|
If you enabled the FlexConnect AP
upgrade in the previous step, you must enable the following parameters:
- Slave
Maximum Retry Count—The number of attempts the slave access point must try to
connect to the master access point for downloading the upgrade image.
If the image download does not occur for the configured retry attempts,
the image is upgraded over the WAN. The default value is 44; the
valid range is between 1 and 63.
- Upgrade Image—Select the upgrade image. The options are Primary, Backup, and Abort.
|
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.
|
Step 7
|
Click Apply.
|
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.