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Cisco Aironet 1500 Series

Field Notice: FN - 62831 - An Access Point (AP) in a Mesh AP (MAP) or Roof Top AP (RAP) Mode May Not Provide Enough Power to be Heard By a Parent AP


July 20, 2007

NOTICE:

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.


Products Affected

Product

AIR1500 - AIR-LAP1510AG-S-K9

Problem Description

An affected AP may not join the network over wireless or may only join the network when in very close proximity to another AP, or may join the network but be unable to provide a sufficient link for children APs to join the network.

An affected AP in Mesh AP (MAP) mode may not provide enough power to be heard by a parent AP.

An affected AP in Roof-top AP (RAP) mode may not provide enough power to be heard by children APs.

Background

Each AP radio is calibrated to ensure consistent performance. The calibration values are programmed into a table in the AP. The AP references this table when it initializes its radios.

During manufacturing, some APs were not programmed with their calibration values. As a result, the AP radios output 0 dBm of power.

For Mesh APs that rely on the radio to connect to the network, the AP will be unable to connect to the network, or may only be able to connect when in very close proximity to the intended parent AP.

For Roof-top APs, the AP will be unable to provide sufficient power for a child AP to connect or will only be able to connect when in very close proximity to the child AP.

Problem Symptoms

In an otherwise correctly configured network, an AP is unable to join the network This may be because the RAP is impacted and its radio does not have enough power to communicate over wireless with a child AP, a MAP is impacted and its radio does not have enough power to communicate over wireless with a parent AP, or both APs are impacted.

Workaround/Solution

Be sure that no other network configuration issues are impacting your network. For instance:

- Be sure the MAC address of the AP is included in the MAC filter list, if use of the MAC filter list is enabled.

- If your AP and Controller are on the same subnet, make sure that your switch can relay the LWAPP discovery broadcast request to the Controller.

- If your AP and Controller will be on different subnets, make sure that that you have configured your DHCP server Option 43 with the Controller's IP Address.

- If your Controller is running a version number 4.0.155.5 or newer, be sure that the following is disabled by running config network allow-old-bridge-aps disable .

If your network is correctly configured, and you have an impacted AP that is not connecting to the network, verify that the power calibration table is the issue by the following.

  1. Using an Ethernet cable, connect the AP to a switch that is capable of reaching the Controller.

  2. From the Controller CLI, run show ap config 802.11a

    If the transmit power information shows 0 dBm for the Power Levels, this unit needs to be replaced .

    For example:

    Tx Power 
    Num Of Supported Power Levels ............. 2 
    Tx Power Level 1 .......................... 0 dBm 
    Tx Power Level 2 .......................... 0 dBm 
    Tx Power Configuration .................... CUSTOMIZED 
    Current Tx Power Level .................... 2
    

3. Contact your account representative to submit a Return Material Authorization (RMA) request using an RMA code of MFG-NEW and ARFN.

If your AP shows a transmit Power Level value of anything other than 0 dBm, please continue to work with TAC to resolve.

Revision History

Revision

Date

Comment

1.0

20-JUL-2007

Initial Public Release

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

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