Converting Autonomous Access Points to Lightweight Mode
Finding Feature Information
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Prerequisites for Converting Autonomous Access Points to Lightweight Mode
Access points that are converted to lightweight mode do not support Wireless Domain Services (WDS). Converted access points communicate only with Cisco wireless LAN switchs and cannot communicate with WDS devices. However, the switch provides functionality that is equivalent to WDS when the access point associates to it.
All Cisco lightweight access points support 16 Basic Service Set Identifiers (BSSIDs) per radio and a total of 16 wireless LANs per access point. When a converted access point associates to a switch, only wireless LANs with IDs 1 through 16 are pushed to the access point unless the access point is a member of an access point group.
Access points that are converted to lightweight mode must get an IP address and discover the switch using DHCP, DNS, or IP subnet broadcast.
Information About Autonomous Access Points Converted to Lightweight Mode
You can convert autonomous Cisco Aironet access points to lightweight mode. When you upgrade the access points to lightweight mode, the access point communicates with the switch and receives a configuration and software image from the switch.
See the Upgrading Autonomous Cisco Aironet Access Points to Lightweight Mode document for instructions on upgrading an autonomous access point to lightweight mode. You can find this document at this URL:
Reverting from Lightweight Mode to Autonomous Mode
After you use the upgrade tool to convert an autonomous access point to lightweight mode, you can convert the access point from a lightweight unit back to an autonomous unit by loading a Cisco IOS release that supports autonomous mode (Cisco IOS Release 12.3(7)JA or earlier releases). If the access point is associated to a switch, you can use the switch to load the Cisco IOS release. If the access point is not associated to a switch, you can load the Cisco IOS release using TFTP. In either method, the access point must be able to access a TFTP server that contains the Cisco IOS release to be loaded.
Using DHCP Option 43 and DHCP Option 60
Cisco Aironet access points use the type-length-value (TLV) format for DHCP option 43. You must program the DHCP servers to return the option based on the access point’s DHCP Vendor Class Identifier (VCI) string (DHCP option 60).
The following table lists the VCI strings for Cisco access points that can operate in lightweight mode.
Cisco Aironet 1140 Series
Cisco AP c1140
Cisco Aironet 3500 Series
Cisco AP c3500
Cisco Aironet 3600 Series
Cisco AP c3600
The format of the TLV block is as follows:
Type: 0xf1 (decimal 241)
Length: Number of switch IP addresses * 4
Value: List of the IP addresses of switch management interfaces
See the product documentation for your DHCP server for instructions on configuring DHCP option 43. The Upgrading Autonomous Cisco Aironet Access Points to Lightweight Mode document contains example steps for configuring option 43 on a DHCP server.
If the access point is ordered with the Service Provider Option - AIR-OPT60-DHCP selected, the VCI string for that access point will be different than those strings listed in the previous table. The VCI string has the following suffix: ServiceProvider. For example, a 1260 with this option returns this VCI string: Cisco AP c1260-ServiceProvider.
The switch IP address that you obtain from the DHCP server should be a unicast IP address. Do not configure the switch IP address as a multicast address when configuring DHCP option 43.
How Converted Access Points Send Crash Information to the Switch
When a converted access point unexpectedly reboots, the access point stores a crash file on its local flash memory at the time of the crash. After the unit reboots, it sends the reason for the reboot to the switch. If the unit rebooted because of a crash, the switch pulls up the crash file using existing CAPWAP messages and stores it in the switch flash memory. The crash information copy is removed from the access point flash memory when the switch pulls it from the access point.
How Converted Access Points Send Radio Core Dump Information to the Switch
When a radio module in a converted access point generates a core dump, the access point stores the core dump file of the radio on its local flash memory at the time of the radio crash. It sends a notification message to the switch indicating which radio generated a core dump file. The switch sends a trap that alerts you so that you can retrieve the radio core file from the access point.
The retrieved core file is stored in the switch flash and can be uploaded through TFTP or FTP to an external server for analysis. The core file is removed from the access point flash memory when the switch pulls it from the access point.
Uploading Memory Core Dumps from Converted Access Points
By default, access points converted to lightweight mode do not send memory core dumps to the switch. This section provides instructions to upload access point core dumps using the switch GUI or CLI.
Displaying MAC Addresses for Converted Access Points
There are some differences in the way that controllers display the MAC addresses of converted access points on information pages in the controller GUI:
On the AP Summary page, the controller lists the Ethernet MAC addresses of converted access points.
On the AP Detail page, the controller lists the BSS MAC addresses and Ethernet MAC addresses of converted access points.
On the Radio Summary page, the switch lists converted access points by the radio MAC address.
Configuring a Static IP Address for a Lightweight Access Point
If you want to specify an IP address for an access point rather than having one assigned automatically by a DHCP server, you can use the controller GUI or CLI to configure a static IP address for the access point. Static IP addresses are generally used only for deployments with a limited number of users.
An access point cannot discover the switch using domain name system (DNS) resolution if a static IP address is configured for the access point, unless you specify a DNS server and the domain to which the access point belongs. You can configure these parameters using either the switch CLI or the GUI.
If you configure an access point to use a static IP address that is not on the same subnet on which the access point’s previous DHCP address was, the access point falls back to a DHCP address after the access point reboots. If the access point falls back to a DHCP address, enter the show ap config generalCisco_AP CLI command to show that the access point is using a fallback IP address. However, the GUI shows both the static IP address and the DHCP address, but it does not identify the DHCP address as a fallback address.
Switch# ap name AP03 static-ip ip-address
184.108.40.206 netmask 255.255.0.0 gateway 220.127.116.11
Configures a static IP address on the access point. This command contains the following keywords and arguments:
ip-address— Specifies the Cisco access point static IP address.
ip-address— Cisco access point static IP address.
netmask—Specifies the Cisco access point static IP netmask.
netmask— Cisco access point static IP netmask.
gateway—Specifies the Cisco access point gateway.
gateway— IP address of the Cisco access point gateway.
The access point reboots and rejoins the switch, and the static IP address that you specify is pushed to the access point. After the static IP address has been sent to the access point, you can configure the DNS server IP address and domain name. You must perform Steps 3 and 4 after the access points reboot.
Enters privileged EXEC mode.
Switch# configure terminal
Enters global configuration mode.
Switch(config)# ap static-ip name-server
Configures a DNS server so that a specific access point or all access points can discover the switch using DNS resolution.
To undo the DNS server configuration, enter the noapstatic-ipname-servernameserver_ip_address command.
Switch(config)# ap static-ip domain domain1
Configures the domain to which a specific access point or all access points belong.
To undo the domain name configuration, enter the noapstatic-ipdomainstatic_ip_domain command.
Returns to privileged EXEC mode. Alternatively, you can also press Ctrl-z to exit global configuration mode.
Switch# show ap name AP03 dot11 24ghz
Displays the IP address configuration for the access point.
Configuring a Static IP Address on an Access Point (GUI)
Choose Configuration > Wireless > AP Summary
The All APs page appears with a list of all access points that are associated with the switch.
Click the name of the access point for which you want to configure a static IP address.
The AP > Edit page appears.
In the IP Config area, select the Static IP check box if you want to assign a static IP address to the access point. The default value is unselected.
Options that enable you to configure a static IP address for the access point appear in the IP Config area.
In the Netmask field, enter the network mask.
In the Gateway field, enter the default gateway address.
Click Apply to commit your changes.
The access point reboots and rejoins the switch, and the static IP address that you specified in Step 4 is sent to the access point.
After the static IP address has been sent to the access point, you can configure the DNS server IP address and domain name by performing the following steps:
In the DNS IP Address field, enter the IP Address of the DNS server.
In the Domain Name field, enter the name of the domain to which the access points belongs.
Click Apply to commit the changes.
Recovering the Access Point Using the TFTP Recovery Procedure
Download the required recovery image from Cisco.com (ap3g2-k9w8-tar.152-2.JA.tar) and install it in the root directory of your TFTP server.
Connect the TFTP server to the same subnet as the target access point and power-cycle the access point. The access point boots from the TFTP image and then joins the switch to download the oversized access point image and complete the upgrade procedure.
After the access point has been recovered, you can remove the TFTP server.
Configuration Examples for Converting Autonomous Access Points to Lightweight Mode
Displaying LSC Information: Example
This example shows how to display the LSC summary:
Displaying the IP Address Configuration for Access Points: Example
This example shows how to display the IP address configuration for the access point:
Switch# show ap name AP03 dot11 24ghz config general
Cisco AP Identifier.............. 4
Cisco AP Name............................. AP6
IP Address Configuration.................. Static IP assigned
IP Address................................ 10.10.10.118
IP NetMask................................ 255.255.255.0
Gateway IP Addr........................... 10.10.10.1
Name Server............................... 10.10.10.205
Displaying Access Point Crash File Information: Example
This example shows how to display access point crash file information. Using this command, you can verify whether the file is downloaded to the switch:
Switch# show ap crash-file
Local Core Files:
The number in parentheses indicates the size of the file. The size should
be greater than zero if a core dump file is available.