Howto:MXR-2 Mobility Exchange - Trapeze - Testreport

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Contents

Summary

Trapeze Networks WiFi Infrastructure supports all required features to provide wireless service for innovaphone IP72 WiFi handset. WMM and U-APSD support enables battery lifetime about 10/40 hours(talk/standby).

Certification Status

The tests for this product have been completed.

Testing of this product has been finalized June 23, 2008.

Version

Firmware Version:

6.0.6.1.0

innovaphone Firmware:

V6 sr2-hotfix5, Build 08-6090068

Testresults

Association and Authentication

Association Authentication Cipher Result
WPA2 Pre-shared Key AES-CCMP OK
WPA2 PEAP-MSCHAPv2*, Username and Password AES-CCMP OK
*RADIUS Server certificate is not validated yet on IP72.

Power Save

With U-APSD and Long-Doze activated a talk time of approx. 10 hours and good voice quality was achieved.

Configuration of IP72

WLAN Settings

Highest security level and longest battery life is achieved with following settings:

  • Security Cipher: AES-CCMP
  • Security Association Mode: WPA2
  • Power Management
    • Power Save: U-APSD
    • Powermode: Long-Doze (both idle and call)

Channels

Enable only 1,6 and 11 channels on Trapeze and set channel mask on IP72 to 0x421(scan only 11,6,1). This will enable faster map building and handover.

Example for Update Server:

config add WLANMGR0 /channel-mask 0x421
config write
config activate
iresetn


Product Setup

Create Wireless Service Profile via RingMaster as usual. Enable RSN(WPA2), PSK Auth and AES(CCMP). Generate Pre-shared Key using passphrase. The settings that affect voice quality and battery lifetime are described further below.

Beacon period

Beacon period of 100ms is recommended. Higher value will increase battery life and decrease throughput. Lower value will decrease battery life and increase throughput.

DTIM Interval

Delivery traffic indication message (DTIM) is information sent as part of a beacon to wireless client informing about buffered data on access point. The recommended value is dependent on beacon period of 100ms is 5.

Data Rates

In the 802.11g configuration:

  • Beacon rate should be set to 6 MBit/s
  • Multicast rate should be set to "automatic"
  • Transmission rate 1, 2, 5.5 should be disabled
  • Transmission rate 6 should be set as mandatory
  • Other rates should be set as supported

If possible do not use 802.11b clients at all, cause this affects data rate of 802.11g clients.

Quality of Service and WMM

In order to use U-APSD power save feature that enables longest battery life time of IP72 its very important to correctly configure DSCP mappings on Trapeze and set ToS values on whole innovaphone infrastructure.

Best practice was to set ToS Priority values on ALL innovaphone components (not only IP72) to following values:

  • 0xb8 for RTP (Expedited Forwarding, codepoint 101110 RFC 2598)
  • 0x68 Signaling (Assured Forwarding 31, low drop, Class 3, codepoint 011010 RFC 2597)

Refer to Howto:The_IPv4_TOS_field_and_DiffServ for more information about ToS and DSCP on innovaphone devices.


Additionally default CoS to DSCP and DSCP to CoS mappings on Trapeze have to be changed:

  • RTP: DSCP 46 shall map to CoS 6 and vice versa.
  • Signaling: DSCP 26 shall map to CoS 4 and vice versa.
set qos dscp-to-cos-map 46 cos 6
set qos cos-to-dscp-map 6 dscp 46 


Without setting correct QoS mappings U-APSD will not work with Trapeze, causing bad sound quality on IP72.

Troubleshooting

The most often problem on VoWiFi setup is the speech quality on IP72. To localize the cause use tools provided by Trapeze wireless switch console.

At first find Sess-ID of handset posing a problem:

MXR-2# show sessions network ssid myssid

User                         Sess  IP or MAC         VLAN            Port/
Name                           ID  Address           Name            Radio
---------------------------- ----  ----------------- --------------- ---------
00:01:3e:10:09:3d              52* 172.16.1.73       default            AP 2/1
00:01:3e:10:09:51              51* 172.16.1.237      default            AP 3/1
00:01:3e:10:0a:16              54* 172.16.1.22       default            AP 1/1
00:01:3e:10:0a:88              53* 172.16.1.193      default            AP 1/1
last-resort-myssid             55* 08:00:28:32:00:00 default            AP 3/1

5 sessions match criteria (of 5 total)


In our example it is 00:01:3e:10:09:51 with Sess-ID 51.

Lets look at clients data:

MXR-2# show sessions mesh-ap session-id 51
Local ID:          51
Global ID:         SESS-51-560f54-608324-fa271b
State:             ACTIVE
SSID:              myssid
VLAN Name:         default
Tag:               3
AP/Radio:          3/1
MAC Address:       00:01:3e:10:09:51
User Name:         00:01:3e:10:09:51
IP Address:        172.16.1.237
Session Start:     Wed Jun  4 19:38:44 2008 GMT
Last Auth Time:    Wed Jun  4 19:38:44 2008 GMT
Last Activity:     Wed Jun  4 19:39:32 2008 GMT  ( <15s ago)
Session Timeout:   0
Idle Time-To-Live: 169
Login Type:        MAC
EAP Method:        NONE, using server 192.168.0.222
Protocol:          802.11 WMM
Session CAC:       disabled
Stats age:         0 seconds
Last packet rate:  54 Mb/s
Last packet RSSI:  -51 dBm
Last packet SNR:   44
                  Packets          Bytes
Rx Unicast                  14429            1539665
Rx Multicast                    5                820
Rx Encrypt Err                  0                  0
Tx Unicast                  14696            2109801

Queue            Tx Packets       Tx Dropped       Re-Transmit
Background                      5                0                0
BestEffort                    523                0                3
Video                           0                0                0
Voice                       13941                0               51

The values you should check here:

  • Protocol - make sure WMM is enabled.
  • Voice Queue - check number of Tx packets. This number have to be significant greater then number of best effort packets (the most packets are RTP packets). If not, check ToS setting on IP-Phones or DSCP mappings on trapeze. UAPSD will not work without correct mapped RTP and signaling packets.
  • Re-Transmit - the number of retransmitted packets should not exceed 20%. Greater retransmission rate will be noticeable on IP72 as packet loss. If so, increase WLAN coverage using more APs.


Known Problems

IP72 used with Trapeze WiFi infrastructure (Nortel) using UAPSD and AES may not work correctly. IP72 may loose connectivity sporadically which again may break calls and registration at gatekeeper. A fix is available with version 6.0.6.1.0 from Trapeze.

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