Yealink SIP-T2 Series User Manual

Administrator’s Guide for SIP-T2 Series/T19(P) E2/T4 Series IP Phones
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2. Select the desired value from the pull-down list of Use Outbound Proxy In Dialog.
3. Click Confirm to accept the change.
SIP Session Timer
SIP session timers T1, T2 and T4 are SIP transaction layer timers defined in RFC 3261. These
session timers are configurable on IP phones.
Timer T1
Timer T1 is an estimate of the Round Trip Time (RTT) of transactions between a SIP client and
SIP server.
Timer T2
Timer T2 represents the maximum retransmitting time of any SIP request message. The
re-transmitting and doubling of T1 will continue until the retransmitting time reaches the T2
value.
Example:
The user registers a SIP account for the IP phone and then set the value of Timer T1, Timer T2
respectively (Timer T1: 0.5, Timer T2: 4). The SIP registration request message will be
re-transmitted between the IP phone and SIP server. The re-transmitting and doubling of Timer
T1 (0.5) will continue until the retransmitting time reaches the Timer T2 (4). The total registration
request retry time will be less than 64 times of T1 (64 * 0.5 = 32). The re-transmitting interval in
sequence is: 0.5s, 1s, 2s, 4s, 4s, 4s, 4s, 4s, 4s and 4s.
Timer T4
Timer T4 represents the time the network will take to clear messages between the SIP client and
server.

Yealink SIP-T2 Series Specifications

General

Brand	Yealink
Model	SIP-T2 Series
Category	IP Phone
Language	English