Welltech SIPPBX 6200 V.3.1.1 - Manual (Page 39)

Welltech Technology Co., Ltd.
SIPPBX 6200S, 6200GS, 6200N Release 3.1.1
User Guide
- 39 -
Advance System Configuration
Start Path: System Core > System > Advance
Figure 4.1-2
Advance Parameter Description:
• Call Validation Time: The timer to check periodically call is valid or not.
SIPPBX 6200x will send re-INVITE periodically for call validation. This
parameter also refers to the session timer RFC 4028 Min-se header. SIP
command 422 will be sent when Session-Expires time is smaller than call
validation time.
• NAT Compare Method: How to detect a NAT user.
- IP Only: Compare IP only
- IP / Port: Compare IP and UDP port
• RetransmissionT1 (msec.): T1 determines several timers which were defined
in RFC3261. For example, when an unreliable transport protocol is used, a
Client Invite transaction retransmits requests at an interval that start at T1
seconds and doubles after every retransmission. A Client General transaction
retransmits requests at an interval that starts at T1 and doubles until it
reaches T2. (Default Value: 500ms) **.
• RetransmissionT2 (msec.): Determines the maximum retransmission interval
Which were defined in RFC3261. For example, when an unreliable transport
protocol is used, general requests are retransmitted at an interval which starts