In the SoftCo documentation, only one domain name is planned in the IMS scenario. Generally, two domain names exist on the live network. As a result, configuration personnel can configure domain names on the IAD, but do not know how to configure the same domain names on the SoftCo.
Configure the domain names on the SoftCo as follows:
Use the domain name for user authentication when setting IMS connection parameters.
Use the SBC domain name when configuring the SIP trunk for connecting to the IMS.