User's Manual

Table 25: Hotline Service configuration parameters
Parameter name Description Default
HOTLINE_ENABLE Indicates if Hotline Service is
enabled or disabled.
No (indicates that Hotline
Service is disabled)
HOTLINE_URL Used as To field of INVITE
message by the SIP IP
Deskphone to notify the
Proxy Server that this is a call
from a Hotline Phone. The
HOTLINE_URL is not a real
URL of the Hotline target.
The IP Deskphone has no
idea about the Hotline target.
The Proxy server replaces
the To field of INVITE request
message with a real Hotline
target when it receives an
INVITE request from the
Hotline Phone.
Hotline
Session Timer Service
The Session
Timer for the Session Initiation Protocol (SIP) feature (RFC4028) allows the Avaya
1100 Series IP Deskphone to support a keep-alive mechanism for SIP sessions. SIP sessions
are periodically refreshed by UPDATE requests (or re-INVITES for the IP Deskphones that do
not support UPDATE). The UPDATE requests are sent during an active call to allow endpoints
or proxies to determine the status of a SIP session.
The Session Timer Service contains the following elements:
• Session-Expires header
• Min-SE header
• response message (422—Session interval too small)
• tag (timer) for existing headers
The SIP IP Deskphone generates, processes and handles the SIP messages that include the
preceding elements.
Session-Expires header
The SIP
Session-Expires header delivers the Session-Expires interval and provides
information about the entity performing the refreshes. A value of "uac" indicates that the
originating endpoint performs the refresh; a value of "uas" indicates that the terminating
Session Timer Service
SIP Software for Avaya 1100 Series IP Deskphones-Administration November 2012 173