Connect Two Cloud Voice Systems

You can join two separate Cloud Voice systems so their extensions can reach each other, for example to connect a headquarters site with a branch office. This page walks through the SIP (Session Initiation Protocol) trunk pairing that establishes the link, using each system’s fully qualified domain name (FQDN) to locate the far end. A trunk is simply the signaling path that carries calls between the two systems.

The connection is built from two matched trunks. One system publishes an Account Trunk that acts as the registration host, and the other system points a Register Trunk at that host and signs in. In the example below, the headquarters system hosts the Account Trunk and the branch system registers to it.

System	What to create
Headquarters Cloud Voice	An Account Trunk
Branch Cloud Voice	A Register Trunk

Note

The two trunks are two halves of one link. The Account Trunk defines the login (username, password, and authentication name) that the far end will use. The Register Trunk uses that same login to sign in and reach the host. Build the Account Trunk first, then the Register Trunk.

Create the Account Trunk on the headquarters system

1. Sign in to the PBX (private branch exchange) web portal of the headquarters system and go to Extension and Trunk > Trunk.

2. Click Add to start a new trunk.

3. Under Basic, set the following:

   

   • Name: A label that helps you recognize this trunk.
   • Trunk Status: Set to Enabled.
   • Select ITSP Template: Choose General.

   Note

   ITSP stands for Internet Telephony Service Provider. The template pre-fills settings for a specific carrier. Because you are connecting to another Cloud Voice system rather than an outside carrier, General is the correct choice.

4. Under Detailed Configuration, define the account the branch system will use to register:

   

   • Trunk Type: Choose Account Trunk.

   • Transport: Choose UDP (User Datagram Protocol).

   • Username: Set a username for the trunk.

     Note

     The username also serves as the trunk number.

   • Password: Set a password to go with the username.

   • Authentication Name: Set the authentication name the branch system will use when it registers.

5. Click Save, then Apply.

Note the username, password, authentication name, and transport you entered here. You will re-enter the same values on the branch system in the next section.

Create the Register Trunk on the branch system

1. Sign in to the PBX web portal of the branch system and go to Extension and Trunk > Trunk.

2. Click Add to start a new trunk.

3. Under Basic, set the following:

   

   • Name: A label that helps you recognize this trunk.
   • Trunk Status: Set to Enabled.
   • Select ITSP Template: Choose General.

4. Under Detailed Configuration, point the trunk at the headquarters system:

   

   • Trunk Type: Choose Register Trunk.
   • Transport: Choose UDP.
   • Hostname/IP: The FQDN of the headquarters system, for example hq.example.com.
   • Port: The SIP registration port of the headquarters system, typically 5060.
   • Domain: The FQDN of the headquarters system again, for example hq.example.com.
   • Username: The username you set on the headquarters Account Trunk.
   • Password: The password you set on the headquarters Account Trunk.
   • Authentication Name: The authentication name you set on the headquarters Account Trunk.

   Caution

   The Transport, Username, Password, and Authentication Name must match exactly what you set on the headquarters Account Trunk, and these values are case-sensitive. A single mismatch stops the trunk from registering and blocks every call between the two systems.

5. Click Save, then Apply.

Confirm the connection

Once both trunks are applied, check that they have come up on each system. A healthy trunk shows a green status indicator ().

• On the headquarters portal, go to Extension and Trunk > Trunk and review the Account Trunk’s status.

  

• On the branch portal, go to Extension and Trunk > Trunk and review the Register Trunk’s status.

  

Tip

If a trunk does not turn green, confirm that the headquarters FQDN resolves to the correct address (a DNS, or Domain Name System, check) and that the SIP port (5060 by default) is reachable through any firewall between the two systems. Then re-check that the credentials and transport match on both ends.

Next steps

The trunk only carries the link between the systems. To let extensions place calls across it, add routes on each system:

• Set up communication from headquarters to branch
• Set up communication from branch to headquarters