Avaya 3641 Installation, Configuration And Administration page 66

Part B: Avaya 3641/3645 Wireless IP Telephone
Band roaming
The a—b-b/g roaming option is not visible on the 802.11 Config menu until the key
sequence *#8 (asterisk-pound-eight) is pressed. Once this sequence is pressed, a
confirmation appears and when the Yes softkey is pressed the a—b-b/g roaming option is
visible and enabled as indicated by the asterisk beside it. Select it to open the sub menu
and set the additional roaming options.
This feature should only be activated when the handsets and network have been
configured specifically for this feature.
When the a -- b-b/g roaming option is selected, a submenu appears so that you can set the
channels for 802.11a and the transmit power for both 802.11a and b-b/g as described
above. The additional settings are Preferred Band and RSSI Threshold. The Preferred
Band is the band which the handset should use unless the signal strength of the current
AP drops below the threshold setting, at which point the handset will roam to the non-
preferred band. The Preferred Band options are a or b & b/g mixed or no preference. Only
one selection may be made. No preference is the default and does not require a threshold
setting. If a or b & b/g mixed are selected, the threshold may be set. The RSSI Threshold
setting allows you to set the signal strength at which the handset will band roam from the
preferred band to the non-preferred band. The info line shows the permitted range for the
threshold entry. The default is -65.
Once made visible, the a—b-b/g roaming option remains visible on the menu and may be
selected or not, as above. The roaming option may again be hidden by pressing the secret
key sequence and pressing the No softkey when the confirmation screen appears. The
roaming option is also hidden when the Restore Defaults option is initiated.
Band roaming notes
• Use a-- b-b/g roaming only if the wireless handset must be able to roam between APs
using these different bands because band roaming can cause lapses in audio and
slightly degraded battery life.
•
All APs must use the same subnet, security and SSID.
•
Due to excessive gaps in audio when roaming, band roaming should not be used with
WPA-Enterprise security types such as PEAP and EAP-FAST.
•
The first band the handset checks when powering up in No preference mode is the B-
band. If no B-band is detected, then the phone switches bands and checks the A-
band.
•
The roam time from B to A will increase proportionally to the number of A channels
enabled. Additionally, passive scan requirements for DFS increase roam delay.
Minimizing the number of enabled A bands is therefore recommended.
•
The letter A or B replaces the radio wave graphic in the signal strength icon on the
handset display when band roaming is active to indicate which 802.11 band is
currently being used by the handset. e.g.
• The handset will beep when it band roams while in a call. This setting may be
disabled/enabled on the Config menu. It is enabled by default.
Setting band roaming parameters using the Handset Administration Tool
The Handset Administration Tool (HAT) can be used to configure band roaming. However,
the band roaming options do not appear on the Network tab unless the .ini file is
modified. Follow these steps to modify the .ini file and display the band roaming options:
66 Avaya Voice Priority Processor, Avaya 3641/3645 Wireless IP Telephone, Handset Administration Tool