Nortel 2245 Installation And Configuration Manual page 69

WLAN IP Telephony Manager 2245 configuration
• The WLAN IP Telephony Manager 2245 server tags/untags packets with
the SVP header. SVP packets have the protocol byte of the IP header set
to 0x77. SVP-compliant APs use this proprietary tagging to give priority
to tagged packets. For UDP (UNIStim and RTP) packets going from the
wireless handset to the network, the WLAN IP Telephony Manager 2245
replaces the SVP protocol number, 0x77, with the UDP number, 0x11.
For packets going from the network to the wireless handset, the protocol
number is changed from 0x11 to 0x77.
Because packets which traverse the network between the wireless
handset and the WLAN IP Telephony Manager 2245 are not standard IP
packets (the packets use a non-standard protocol number), there can no
Layer 3 routing in the path. Therefore, the wireless handsets and WLAN
IP Telephony Managers 2245 must be in the same logical subnet.
• RTP packets between the wireless telephone and the WLAN IP
Telephony Manager 2245 always contain 30 ms worth of voice, no
matter what has been configured on the Call Server. The WLAN IP
Telephony Manager 2245 repackages the RTP packets to conform to the
size which has been configured in the Call Server. This provides more
efficient use of the available Radio Frequency (RF) bandwidth at the
expense of slightly increased jitter and latency.
• The WLAN IP Telephony Manager 2245 is configured with a maximum
allowable number of simultaneous media streams on a single AP. The
WLAN IP Telephony Manager 2245 keeps track of the number of media
streams on each AP and blocks calls to/from a wireless handset which
would exceed the configured capacity. For more information on call
blocking, refer to "Call blocking" on
There is a keep-alive packet exchange which runs between the wireless
handset and the WLAN IP Telephony Manager 2245 every 30 seconds. If the
wireless handset detects the WLAN IP Telephony Manager 2245 is
unreachable, the wireless handset resets itself and attempts to re-establish a
connection with the master WLAN IP Telephony Manager 2245.
page
WLAN IP Telephony
Page 69 of 206
54.
Installation and Configuration