IMS SIP Trunk Registration Guide for Yeastar Gateways


  • PBX Model: Gateways
  • Firmware version: TA



The client might have a dedicated IMS SIP trunk from the provider. This kind of SIP trunk usually offers a dedicated cable to be connected with which comes from a specific ISP router, and it's exclusive for voice only without Internet access function.

Have already one similar guide: SIP Dedicated Trunk Application for S-Series VoIP PBX, it is not for IMS trunk as the IMS trunk has something different.



The cases about we have connected the IMS SIP trunk successfully:

  • IMS Vendor: Huawei, ZTE
  • IMS provider: Claro, Telefonica, China Mobile, OTE Greece, Etislalat UAE etc...

IMS SIP trunk mainly follows the 3GPP and SIP RFC3261 protocol. Different countries may have slightly different localize parameters, but not big. Therefore this guide could cover most cases. 


Network Environment

Here is the topology sample:


Here we have a sample:

The IMS SIP trunk interface IP address and SIP trunk Information are offered by the carrier in the practical case.

Gateway LAN

IP address:



ISP Router Interface offered

IP address:



IMS SIP Trunk IP address:



1. Network Settings

  • Fill in the IP address accordingly as the above table mentions.
  • Set 2 IP address for the LAN port


Add a static route for the IMS SIP trunk. Here we the */24 segment of the IMS SIP trunk address. 


This is to make sure the media server of the IMS SIP trunk can be communicated correctly as well. Because sometimes the media server IP address is different from the SIP trunk registration server IP address. But in most cases, a 24 netmask could cover the range.


2. Firewall Settings

For a similar reason as the static route, we add firewall accept rule for the IMS SIP trunk. Also, in most cases, a 24 netmask could cover the range.



3. SIP Trunk Settings

Go to the VoIP Server menu and add 1 SIP trunk. You could use Template Register mode and let all FXS ports use the same IMS trunk to make outbound calls.


Parameter Tips

  • Hostname/IP: the IP address/domain of the IMS SIP trunk server. For example,
  • Port: by default, it is 5060.
  • Domain: the domain of the IMS SIP trunk server. For example,
  • User Name: the phone number of the IMS SIP trunk, usually it starts with prefix +.  For example, +86592123456
  • Authentication Name:  use the format - Username@Domain. For example,
  • From User:  it is the same as the Username. For example, +86592123456
  • Caller ID: +86592123456



3. FXS Port Settings

Go to each port and configure the VoIP Server template as the IMS SIP trunk.


Parameter Tips

  • Caller ID Name: +86592123456
  • Caller ID Number: +86592123456
  • DID Number: +86592123456
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