The Create External Trunks page has two sections. The upper section contains the base settings needed for an External Trunk. The lower section, which consists of a series of collapsible sections, contains other settings that you can use to refine your external trunk configuration. 

Genesys Cloud recommends that you rely on the base BYOC Cloud trunk settings described in this article. However, if your carrier has other requirements, you can use the additional settings to refine your external trunk configuration. For more information, see Configure advanced external trunk settings. 

There are two types of BYOC Cloud trunks (BYOC Carrier or BYOC PBX) that you can select depending on how your telephony system is set up. Each trunk type also has a subtype that is designed to narrow down the settings that are required for that type of trunk. For the BYOC PBX trunk type, there is only one subtype. For the BYOC Carrier trunk type, there are three subtypes: One is a generic subtype that you can use for most carrier configurations. The second is a Verizon-specific subtype that you use if Verizon is your carrier. The third is a WhatsApp-specific subtype that you choose if you are using WhatsApp Business Calling.

If you need more information about any of the settings on the External trunk page, see External trunk settings.

Configure an external trunk

1. Click Menu > Digital and Telephony > Telephony > Trunks.
2. Click the External Trunks tab.
3. Click Create New.
4. In External Trunk Name, enter a trunk name.
5. From the Type lists, select the type and subtype for the BYOC Cloud trunk you want to create.

6. Set Trunk State to In-Service.
7. Select the appropriate trunk transport protocol from the Protocol list.
   Note: Genesys Cloud selects the recommended protocol by default. In most situations, this protocol is best protocol for the selected trunk type. For more information, see Choose a trunk transport protocol.

8. Under Inbound select your Number Plan Site. This setting allows you to identify the site with the number plan that you want to use. For more information, see Improve inbound call handling with the Number Plan Site feature.
9. Configure the appropriate SIP routing settings for your trunk subtype:

10. If you cannot use either the FQDN or the TGRP format for the inbound SIP termination identifier, enable DNIS Replacement Routing.

11. Under Outbound,  enter the appropriate identifiers in the Outbound SIP Termination FQDN, Outbound SIP TGRP Attribute, and Outbound SIP DNIS boxes to configure your outbound request URI.

12. To specify any SIP Servers or Proxies enter a value in the Hostname or IP Address box, a port number in the Port box, and then click Add . 
13. Choose the appropriate Digest Authentication setting.
    • If you enable Digest Authentication, you must specify the associated Realm, and the User Name, and Password to use as the authentication credentials.
14. Under Caller ID, specify the Caller Address and Caller Name for the trunk and then use the Prioritized caller ID locations to specify the location from which and order in which you want to display caller ID information to the call recipient.

15. Under SIP Access Control, you can build a list of IP or CIDR addresses to which you want to permit SIP access. To do so, enter an address and click Add . If you configure a BYOC WhatsApp Business Calling trunk, the Allow the Following Addresses section prepopulates with the necessary IP addresses. 
16. If you are configuring a BYOC PBX trunk, the PBX Passthrough setting appears.
    • Enable this setting if you want to allow your PBX to pass calls intended for the PSTN directly through Genesys Cloud.

17. If you are configuring a Verizon BYOC Carrier trunk subtype, you must configure a few Verizon-specific settings in the Custom SIP headers section.

For more information, see Configure Custom SIP headers.

18. Click Save External Trunk.

For more information about any of the settings on the Create/Edit External Trunk page, see External trunk settings.