User's Manual
GXP2130/GXP2140/GXP2160/GXP2170/GXP2135   
ADMINISTRATION GUIDE 
Page 34 of 85 
to  the  STUN  server.  If  NAT  type  is  Full  Cone,  Restricted  Cone  or 
Port-Restricted Cone, the phone will try to use public IP addresses and port 
number in all the SIP&SDP messages. The phone will send empty SDP packet 
to the SIP server periodically to keep the NAT port open if it is configured to be 
"Keep-alive". Configure this to be "No" if an outbound proxy is used. "STUN" 
cannot  be used if the detected NAT is symmetric NAT. Set this to "VPN" if 
OpenVPN is used. 
Proxy-Require 
A  SIP  Extension  to  notify  the  SIP  server  that  the  phone  is  behind  a 
NAT/Firewall. Do not configure this parameter unless this feature is supported 
on the SIP server. 
Account x  SIP Settings  Basic Settings 
TEL URI 
If the phone has an assigned PSTN telephone number, this field should be set 
to  "User=Phone".  Then  a  "User=Phone"  parameter  will  be  attached  to  the 
Request-Line  and  "TO"  header  in  the  SIP  request  to  indicate  the  E.164 
number.  If  set  to  "Enable",  "Tel:"  will  be  used  instead  of  "SIP:" in  the  SIP 
request. The default setting is "Disable". 
SIP Registration 
Selects  whether  or  not  the  phone  will  send  SIP  Register  messages  to  the 
proxy/server. The default setting is "Yes". 
Unregister On Reboot 
If set to "Yes", the SIP user's registration information will be cleared when the 
phone reboots. The SIP Contact header will contain "*" to notify the server to 
unbind the connection. The default setting is "No". 
Register Expiration 
Specifies  the  frequency  (in  minutes)  in  which  the  phone  refreshes  its 
registration with the specified registrar. The default value is 60 minutes. The 
maximum value is 64800 minutes (about 45 days). 
Reregister Before 
Expiration 
Specifies  the  time  frequency  (in  seconds)  that  the  phone  sends   
re-registration request before the Register Expiration. The default value is 0. 
Local SIP Port 
Defines  the local  SIP port  used to  listen  and transmit.  The  default value is 
5060for Account 1, 5062 for Account 2, 5064 for Account 3, 5066 for Account 
4, 5068 for Account 5, 5070 for Account 6.The valid range is from 1 to 65535. 
SIP Registration Failure 
Retry Wait Time 
Specifies  the  interval  to  retry  registration  if  the  process  is failed.  The  valid 
range is 1 to 3600. The default value is 20 seconds. 
SIP T1 Timeout 
SIP T1 Timeout is an estimate of the round trip time of transactions between a 
client  and  server.  If  no  response  is  received  the  timeout  is  increased,  and 
request  re-transmit retries  would  continue  until  a maximum amount  of  time 
define by T2.The default setting is 0.5 seconds. 
SIP T2 Timeout 
SIP T2 Timeout is the maximum retransmit time of any SIP request messages 
(excluding  the  INVITE  message).  The  re-transmitting  and  doubling  of  T1 
continues until it reaches the T2 value. The default setting is 4 seconds. 










