Yealink T5 Series Administrator's Guide

General Features
411
Default 4
Web UI Settings->SIP->SIP Session Timer T2 (2~40s)
Parameter sip.timer_t4 <y0000000000xx>.cfg
Description
It configures the SIP session timer T4 (in seconds).
T4 represents the maximum duration a message will remain in the network.
Permitted
Values
Float from 2.5 to 60
Default 5
Web UI Settings->SIP->SIP Session Timer T4 (2.5~60s)
Session Timer
Session timer allows a periodic refresh of SIP sessions through an UPDATE request, to determine whether a SIP session
is still active. Session timer is specified in RFC 4028. The phones support two refresher modes: UAC and UAS. Whether
the endpoint functions as a UAC or a UAS depends on the UA that initiates the SIP request. If the initiator is configured
as UAC, the other client or the SIP server will function as a UAS. If the initiator is configured as UAS, the other client or
the SIP server will function as a UAC. The session expiration is negotiated via the Session-Expires header in the INVITE
message. The negotiated refresher is always the UAC and it will send an UPDATE request at the negotiated session expir-
ation. The value “refresher=uac” included in the UPDATE message means that the UAC performs the refresh.
Example of UPDATE message (UAC mode):
UPDATE sip:1058@10.10.20.34:5060 SIP/2.0
Via: SIP/2.0/UDP 10.10.20.32:5060;branch=z9hG4bK2104991394
From: "10111" <sip:10111@10.2.1.48:5060>;tag=2170397024
To: <sip:1058@10.2.1.48:5060>;tag=200382096
Call-ID: 4_1556494084@10.10.20.32
CSeq: 2 UPDATE
Contact: <sip:10111@10.10.20.32:5060>
Max-Forwards: 70
User-Agent: Yealink T58 58.80.0.5
Session-Expires: 90;refresher=uac
Supported: timer
Content-Length: 0
Topic
Session Timer Configuration
Session Timer Configuration
The following table lists the parameters you can use to configure session timer.
Parameter
account.X.session_timer.enable
[1]
<MAC>.cfg

Yealink T5 Series Specifications

General

Brand	Yealink
Model	T5 Series
Category	IP Phone
Language	English