A Trunk is a connection between Webex Calling and the premises, which terminates on the premises with a local gateway or other supported device. Once you create a trunk, you can assign it to a route group. A Route Group is a group of trunks that allow Webex Calling to distribute calls over multiple trunks or to provide redundancy. A Local Gateway is the on-premises device(s) that interconnects the trunk, on-premises PSTN and/or PBX.

Trunks, route groups, and dial plans provide the following benefits:

  • Load-balancing and failover across trunks to Webex Calling and the premises

  • Ability for Webex Calling users to utilize cloud PSTN (CCP or Cisco PSTN) and still be able to reach PBX users in the enterprise

  • Routing of calls to different premises PBX’s

  • Tandem functionality to route calls between premises PBX’s

  • Broader range of migration and co-existence scenarios with premises PBX’s, including mixed sites with premises users and Webex Calling users

  • In-depth visibility of call routing decisions

Once your location is enabled, you must set up PSTN connectivity for Webex Calling users within that location. The following PSTN options are available:

  • Cisco PSTN – Choose this option if you’d like a bundled solution that allows you to order new PSTN numbers and port existing numbers to Cisco. The Cisco PSTN option is only available under the following conditions:

    • You have purchased and enabled the Cisco Calling Plan.

    • The location is in a country where Cisco Calling Plan is supported.

  • Cloud Connected PSTN – Choose this option if you’re looking for a cloud solution that doesn’t require deployment of local hardware, and then select a CCP provider of choice. Cloud PSTN (Cisco PSTN or Cloud Connected PSTN) can only be used to provide PSTN access for Webex Calling users. Calls originating from premises users can’t access cloud PSTN.

  • Premises-based PSTN (Local Gateway) – Choose this option if you want to keep your current PSTN provider. Trunks for premises-based PSTN through local gateway can also be used to connect to premises PBXs. You can retain existing local gateway functionality is retained without making any configuration changes. Locations using local gateway are set to Premises-based PSTN and local gateways become trunks.

Configure your selected PSTN connection within Control Hub by selecting Calling > Locations, select the location you want to modify, then select Assign or Manage and select the PSTN connection of choice.

A trunk is the connection between Webex Calling and the premises, terminating on the premises with a local gateway or other supported device.

Before you begin

All trunks must be assigned to a location within Control Hub.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Call Routing, and then select Add Trunk.

2

Select a location and name the trunk.


 
The name of the trunk can't be more than 24 characters long.
3

Click Save.

What to do next

The trunk information appears on the screen Register Domain, Trunk Group OTG/DTG, Line/Port, Outbound Proxy Address. We recommend that you copy this information from Control Hub and paste it into a local text file or document so you can refer to it when you’re ready to configure the local gateway. If you lose the credentials, you must re-generate them from the trunk information screen in Control Hub. Click Retrieve Username and Reset Password to generate a new set of authentication credentials to use on the trunk.

Note: This action impacts service, so it's recommended to be done during non-business hours.

You can edit the trunk name or view the trunk details and usage in Control Hub.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Call Routing > Trunk.

2

Select the trunk you want to view or modify.

3

On the side panel, next to the trunk name, click the icon to change the name of the trunk.

You can also view the usage information for the trunk.

4

To view additional trunk details, click Manage next to Trunk Info.


 

Use this setting if you lose the trunk information credentials and need to regenerate them. Click Retrieve Username and Password to generate a new set of authentication credentials to use on the trunk. This is service impacting.

You can delete a trunk as long as it's not in use.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Call Routing.

2

Select the trunk you want to delete.

3

From the Actions drop-down menu, click Delete Trunk.

Before you begin

  • Add trunks before configuring a route group.

  • Route groups can include configured trunks from multiple locations.

  • Trunks can be configured singularly or assigned to a route group. Add trunks to route groups to provide redundancy and scalability.

  • Each route group must include at least one trunk with a maximum of 10 trunks per route group.

  • When configuring a route group, you set a priority level to the trunks within that route group. This setting enables calls to be routed in a load-balanced manner.

  • Calls are distributed randomly among trunks with the same priority. If a trunk that is set as highest priority is not available, the system attempts to route the call to a trunk with a lower priority setting. For example:

    • Trunk 1 and Trunk 2 are set at priority level 1.

    • Trunk 3 is set at priority level 2.

    • Webex Calling routes calls to Trunk 1 and Trunk 2 in a load-balanced manner.

    • If Trunk 1 and Trunk 2 are unreachable, calls are routed to Trunk 3.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Call Routing.

2

Select Route Group > Create Route Group.

3

Name the route group, then select the trunk(s) to add from the drop-down menu.

4

Select the priority level for the trunk.

5

Click Save.

What to do next

From the confirmation screen, you can visit the Locations page to configure the PSTN connection to individual locations, or you can visit the Dial Plans page to use this route group as the routing choice for a dial plan.

You can change an existing route group's name, add trunks, modify the number of trunks assigned, and change the trunk priority levels. From the route group details page, you can also view the Calls to On-Premises Extensions, Dial Plans, and PSTN Connection.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Call Routing > Route Groups.

2

Select the route group you want to modify.

3

On the side panel, next to the route group name, click the icon to change the name of the route group.

4

To add or edit trunks in the route group, click Manage next to Trunks.

You can add a trunk from the drop-down menu, edit the priority level of an existing trunk within the table, and/or delete an existing trunk from the table.

5

Click Save.

You can delete a route group as long as it's not in use.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Call Routing > Route Groups.

2

Select the route group you want to delete.

3

From the Actions drop-down menu, click Delete Route Group.

Dial plans allow you to route calls to on-premises destinations by use of trunks or route groups. They are configured globally for an enterprise and apply to all users, regardless of location. A dial plan also specifies the routing choice (trunk or route group) for calls that match any of its dial patterns. Specific dial patterns can be defined as part of your dial plan. A dial pattern represents on-premises extensions:

  • ESN/on-net numbers

  • +E.164 patterns

  • SIP URI domains

Numeric Dial Patterns

Numeric patterns can either represent E.164 numbers or enterprise numbers. Patterns for E.164 numbers start with a leading +, followed by a sequence of digits (1-9), and then optional wildcard characters.

Enterprise Dial Pattern

An enterprise dial pattern is represented by a sequence of digits (1-9), followed by optional wildcard characters. Valid wildcard characters are ! (matches any sequence of digits) and X (matches a single digit, 0-9). The ! wildcard can only occur once at the end and only in an E.164 pattern.

Enterprise Dial Plan Examples

+1408555XXXX

11-digit +E.164 number starting with +1408555

+14085551234

Exact dial string +14085551234

+496100!

Any dial string starting with +496100

84969XXX

8-digit ESN starting with 84969

84969764

Exact 8-digit ESN 84969764

SIP URI Dial Pattern Syntax:

Only domains (right-hand side of SIP URI after @) are matched. Options are either:

  • Fully qualified domain

  • Domain with a leading * (indicating all sub-domains of given domain)

Examples:

SIP URI Dial Patter Syntax Examples

Prefix

Meaning

Examples

example.com

Only URIs with host portion “example.com”

alice@example.com

us.example.com

Only URIs with host portion “us.example.com”

alice@us.example.com

*.example.com

URIs with host portion being sub-domain of “example.com”

alice@eu.example.com

alice@sales.us.example.com

Note: alice@example.com is not matched

Once you’ve created your trunks and route groups, you can configure a dial plan in Control Hub.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Call Routing.

2

Click Dial Plans, then Create Dial Plan.

3

Enter a Name for the dial plan.

4

Select a Routing Choice.

Select either a previously created trunk or route group.

5

(Optional) You can manually create or import a dial pattern for the route choices selected.

6

Click Save.

What to do next

You can also bulk-add dial patterns after your dial plan is created. To bulk-add dial patterns using a CSV file, go to the Dial Plans screen and select the Actions drop-down menu from the dial plan to edit, and then choose Import Dial Patterns CSV or Export Dial Patters CSV. Choose Download Template or Import CSV File and click Submit.

You can change an existing dial plan's name, routing choices, and dial patterns in Control Hub.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Call Routing > Dial Plans.

2

Select the dial plan you want to modify.

3

On the side panel, next to the dial plan name, click the icon to change the name of the dial plan.

4

To change the Routing Choice choose another option from the drop-down menu.

5

To manually add a new dial pattern, click Add dial patterns. Or click Import CSV to bulk-add dial patterns.

6

To remove a dial pattern, click the icon next to the dial pattern you would like to remove.

7

Click Save.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Call Routing > Dial Plans.

2

Select the dial plan you want to delete.

3

From the Actions drop-down menu, click Delete Dial Plan.

You can enable the Calls to On-Premises Extensions setting in Control Hub. This setting applies to users within a location that are registered to a PBX and allows you to route unknown extensions (calling number length of 2-6 digits) to the PBX using an existing trunk or route group.

Before you begin

The Calls to On-Premises Extensions setting is enabled per location.

This setting allows preservation of dialing habits in a mixed cloud/premises environment. Users can continue to use abbreviated dialing (for example, 4 digits), even if the site is partially migrated to Webex Calling.

When enabled, calls made by users at the location to an unknown extension (between 2-6 digits) are routed to the selected route group/trunk as premises calls.

Calls routed through trunks at the location from an unknown extension are handled as premises calls.

Calls are considered as originating from an unknown extension when the caller ID does not match any of the existing dial plan patterns.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Locations.

2

Select the location to modify.

3

On the panel, click Internal Dialing.

4

Check the box next to Enable routing unknown extensions to the Premises as internal calls to enable this setting.

5

Select a routing choice from the drop-down menu.

6

Click Save.

In Control Hub you can configure call routing settings between Webex Calling and premises. These settings determine how your unknown numbers are handled when using trunks and route groups to an on-premises PBX, and the caller ID format for calls routed between Webex Calling and your PBX.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Service Settings.

2

Scroll to Call Routing between Webex Calling and premises and choose how you would like to handle unknown numbers.

  • Standard Behavior is the default and recommended option to achieve the best level of interoperability with an on-premises PBX.
  • Legacy Behavior (not recommended) provides backward compatability for the legacy local gateway behavior and is not recommended when dial plans are configured for the organization.

 

The unknown number handling service setting is set to Legacy Behavior to preserve routing behavior. This setting can be modified to take advantage of new call routing features (for example, dial plans and route groups).

3

Choose your caller ID format.


 

When the +E.164 phone number option is chosen, Webex Calling selects the external Calling Line ID (CLID), which is an E.164 number. When the ESN (enterprise significant number) option is chosen, Webex Calling selects the internal CLID, which is an ESN.

4

Click Save.

The Verify Call Routing tool in Control Hub provides:

  • Simulation of calls to analyze routing decisions.

  • Useful guidance during the design and configuration phases of a deployment.

  • Events in Webex Analytics Platform that include call routing decisions.

  • Support in troubleshooting instances.

1

From the customer view in https://admin.webex.com, go to Services > Calling > Call Routing.

2

Select Verify Call Routing.

3

From the drop-down menus, select a user or a trunk to verify.

4

Enter a number or URI.

5

Click See Routing Result to view the call routing.

Example 1: Multi-site PBX

Deployment description

  • Enterprise customer with 100 sites across US.

  • Multi-site PBX deployment (or network of PBX’s), with main PBX spread over two main sites for HA.

  • 8-digit enterprise dial plan: 8 + 3-digit site code + 4-digit extension.

  • 30 sites remain on-premises, 70 sites move to Webex Calling. PSTN remains on-premises, through SIP Trunks at the two main sites.

  • No mixed sites. For each site users are either all on-premises or all cloud-registered.

Deployment solution

  • Single Dial Plan with 30 E.164 + 30 ESN patterns that routes calls for the on-premises users to a Route Group with two Trunks, terminating on two local gateways at the two main sites.

Example 2: Mixed Cloud-PBX sites

Deployment description

  • Enterprise customer with 50 sites across the US: 10 large sites and 40 small branches.

  • PBX’s at large sites, key switches at branches.

  • 7-digit Enterprise dial plan: 8 + 2-digit site code + 4-digit extension.

  • Webex Calling only at branches, slow migration from PBX’s at large sites (mixed sites with both Webex Calling and PBX users).

  • Cloud-connected PSTN for all cloud users (premises users continue to use existing PSTN).

  • Cloud and PBX users at each large site must retain extension-only dialing capabilities.

Deployment solution

  • Dial plans to route calls to each of the PBX’s from any other site. Also, for each large site, Calls to On-Premises Extensions configured to route calls to a trunk that terminates on a local gateway at the site.

Configurable Limitations for Trunks, Route Groups, and Dial Plans

Description

Maximum Limitation

Dial patterns that a CSV can upload to a dial plan

10000

Trunks that can be configured per location

100

Route groups per enterprise customer

10000

Trunks configurable within a route group

10

Dial plans configurable per enterprise customer

10000

Dial patterns configurable with one dial plan

10000