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Cisco Aironet 340 Series

Field Notice: Cisco Aironet 340 Series: Rate Shifting Not Achieved Outside of 11 Mbps Range


Updated February 5, 2002

June 29, 2000



Products Affected

Product

Comments

PCI4810B

Aironet 11Mbps DSSS PCI Adapter with 40-bit WEP

PCI4820B

Aironet 11Mbps DSSS PCI Adapter with 128-bit WEP

PC4800B

Aironet 11Mbps DSSS PC Card Adapter

PC4810B

Aironet 11Mbps DSSS PC Card Adapter with 40-bit WEP

PC4820B

Aironet 11Mbps DSSS PC Card Adapter with 128-bit WEP

LM4800B

Aironet 11Mbps DSSS PC Card Adapter without antenna

LM4810B

Aironet 11Mbps DSSS PC Card Adapter without antenna with 40-bit WEP

LM4820B

Aironet 11Mbps DSSS PC Card Adapter without antenna with 128-bit WEP

AP4801B

Aironet 11Mbps DSSS Access Point with 2 RP-TNC connectors

AP4821B

Aironet 11Mbps DSSS Access Point without 40-bit WEP and 2 integrated antennas

AP4823B

Aironet 11Mbps DSSS Access Point with 40-bit WEP and 2 RP-TNC connectors

AP4810B

Aironet 11Mbps DSSS Access Point with 40-bit WEP and 1 integrated antenna

AP4820B

Aironet 11Mbps DSSS Aceess Point with 128-bit WEP and 2 integrated antennas

AP4822B

Aironet 11Mbps DSSS Access Point with 128-bit WEP and 2 RP-TNC connectors

AIR-PCM340

340 Series 11 Mbps DSSS PC Card Adapter

PCM341

340 series 11Mbps DSSS PC Card Adapter with 40-bit WEP

AIR-PCM342

340 series 11Mbps DSSS PC Card Adapter with 128-bit WEP

PCM342US

340 series 11Mbps DSSS PC Card Adapter with 128-bit WEP (US Version)

AIR-LMC340

340 series 11Mbps DSSS PC Card Adapter without antenna

AIR-LMC341

340 series 11Mbps DSSS PC Card Adapter with 40-bit WEP without antenna

AIR-LMC342

340 series 11Mbps DSSS PC Card Adapter

AIR-AP340E2C

340 series 11Mbps DSSS AP with 2 integrated antennas

AP340E2R

340 series 11Mbps DSSS AP with 2 RP-TNC connectors

AIR-AP341E2C

340 series 11Mbps DSSS AP with 40-bit WEP and 2 integrated antennas

AIR-AP341E2R

340 series 11Mbps DSSS AP with 2 RP-TNC connectors

AIR-AP341S1C

340 series 11Mbps DSSS AP with 40-bit WEP and 1 integrated antenna

AIR-AP342E2C

340 series 11Mbps DSSS AP with 128-bit WEP and 2 integrated antennas

AIR-AP342E2R

340 series 11Mbps DSSS AP with 128-bit WEP and 2 RP-TNC connectors

AIR-AP342E2RUS

340 series 11Mbps DSSS AP with 128-bit WEP and 2 RP-TNC connectors (US Version)

AIR-PCI340

340 series 11Mbps DSSS PCI Adapter

AIR-PCI341

340 series 11Mbps DSSS PCI Adapter with 40-bit WEP

AIR-PCI342

340 series 11Mbps DSSS PCI Adapter with 128-bit WEP

Problem Description

Customers experience a loss of communication on their Wireless LAN when roaming beyond the 11Mbps coverage area.

Background

Auto Rate Shifting is an 802.11 defined Wireless LAN feature that enables users to increase coverage area beyond the 11Mbps coverage area by decreasing data rate. Most Cisco Aironet 340 Series customers design their Wireless LAN to provide full 11Mbps coverage, and tend not to take advantage of this feature.

The factory default setting is 11Mbps with automatic data rate shifting to the lower speeds: 5.5Mbps, 2Mbps, and 1Mbps.

Problem Symptoms

Customers who configure the radio to run at the lower speeds, or who anticipate rate shifting to the lower speeds, will not experience greater coverage (or range) than the 11Mbps coverage.

When the client roams beyond the 11Mbps coverage area, the rate shift down to 5.5Mbps, 2Mbps, and finally 1Mbps occurs almost instantaneously and does not provide any additional range. The user perception is that communication drops off immediately beyond the 11Mbps coverage area.

Workaround/Solution

Auto rate shifting is a hardware issue. Complete Access Point and Client Adapter replacement is required to enable this feature.

If you are experiencing this rate shifting issue, please contact the Technical Assistance Center (TAC) to process a return materials authorization (RMA).

For Cisco branded Access Points (AIR-AP34x) and PCI adapters (AIR-PCI34x) , the starting serial number enables auto rate shifting. Anything below these values will require a replacement.

Note:?Products with serial numbers containing -88- will not require a replacement.

For Cisco branded PC Cards (AIR-PCM34x and AIR-LMC34x), only those with the part number format 4xx-xxxxxx-006 will require a replacement.

Note:?The part number is located above the bar code.

Product Model Number

Serial Number

AIR-AP342E2C

1EF99002524

AIR-AP341E2C

1EC99001258

AIR-AP342E2R

1EG99003637

AIR-AP341E2R

1ED99001128

AIR-AP341S1C

1EE99001247

AIR-AP340E2C

1EA99001196

AIR-AP340E2R

1EB99001165

AIR-AP342E2RUS

1EJ99004336

AIR-PCI340

1CH99001342

AIR-PCI341

1CJ99001108

AIR-PCI342

1CK99002930

Product Model Number

Serial Number

AIR-PCM340

ends in -009

AIR-PCM341

ends in -009

AIR-PCM342

ends in -009

AIR-PCM342US

ends in -009

AIR-LMC340

ends in -009

AIR-LMC341

ends in -009

AIR-LMC342

ends in -009

For the Aironet-branded products, all serial numbers and part numbers (for PC Cards) apply.

DDTS

To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.

DDTS

Description

CSCav00128

Ap stays at 11mb rate until reaching max sensitivity

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: