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Last updated: 20 March 2026

Fusion for SIP Trunking Module (Admin View – Process & Functionality)

Module Purpose

Fusion for SIP Trunking provides an automated trunking lifecycle within the portal. It allows administrators to provision, configure, and maintain SIP trunks for different target environments, including IP PBXs, IADs, Microsoft Teams, and similar destinations. The goal is to centralise trunk configuration, reduce manual SBC operations, and align commercial entitlements with technical service delivery.

Administrative Entry Points

In addition to standard configuration items for Fusion (Numbers, Addresses and Settings), the SIP Trunking module also includes:

• Trunks – the main operational area for creating and managing trunks

These menu areas work together rather than in isolation. In practice, the administrator first confirms entitlement and inventory, then allocates numbers, and finally configures or updates the SIP trunk itself.

SIP Trunk Provisioning Flow

A stepwise SIP trunk administration flow is typically as follows:

1. Confirm that the tenant subscription contains the necessary SIP trunking and number entitlements
2. Review available numbers and assign relevant DIDs where required
3. Validate address information if regulatory or emergency-calling compliance requires it
4. Open the Trunks menu and create the required trunk type
5. Review the synchronisation status to confirm provisioning alignment with the SBC
6. Configure high-level trunk behaviour
7. Configure detailed tabs such as capacity, DIDs, calling restrictions, and access trunks
8. Save and validate operational state

The trunk list shows the trunk type, current SBC synchronisation status, and deletion options. This gives administrators both lifecycle visibility and provisioning confidence.

High-Level Trunk Controls

At the top of the trunk configuration view, administrators can typically control:

Disaster Recovery

When enabled, disaster recovery redirects calls to the configured recovery destination. This takes precedence over other routing actions such as rewrite, divert, or forwarding logic. Administrators should therefore treat disaster recovery as an overriding control and configure it carefully.

Inbound / Outbound Activation

Inbound and outbound calling can be activated or deactivated at trunk level, allowing operational control during rollout, migration, troubleshooting, or staged service activation.

Trunk Configuration Tabs

Details & Settings

This tab is used for core trunk identity and presentation settings, including trunk name, billing identifier, and presentation-number formats. It also exposes synchronisation visibility with the SBC, allowing the administrator to confirm whether the configured settings have been provisioned successfully into the call-control environment.

Capacity

This tab controls simultaneous call limits. Capacity can be managed at trunk level or subscription level, depending on the service model and operational requirement. Administrators should verify where the effective limit is applied before making capacity changes.

DIDs

The DIDs tab allows the administrator to assign one or more numbers to a trunk. One DID can be marked as the pilot number. Individual DIDs can have routing-related behaviours such as:

• Rewrite – modify the number for routing purposes
• Divert – commonly used during migration to keep services reachable
• Per-DID disaster recovery – redirect calls for that specific number if needed

This gives administrators granular DID-level behaviour without requiring a separate trunk for every scenario.

Call Barring

This tab allows explicit barring of incoming and outgoing calls and is part of the earliest stages of call processing control. It is useful for hard restriction scenarios.

Block List and Allow List

These tabs operate as exceptions relative to broader call policy. A Block List can prohibit calls that would otherwise be allowed, while an Allow List can explicitly permit calls that would otherwise be blocked. This enables controlled local exceptions without requiring a full change to group-level policy.

Calling Plan

The Calling Plan classifies call destinations, for example premium numbers, by country and prefix. Options are defined at Group level and then exposed for tenant trunk configuration. Some items may require administrator approval and can appear with a lock indicator. Calling Plan evaluation is executed after the relevant group-level block-list logic.

Access Trunks

The Access Trunks tab is used to manage the underlying connection points and routing endpoints associated with a trunk. It is a critical area for resilience, failover, and detailed SBC-related configuration. Each access trunk can define settings such as:

• Locale
• Private Realm
• Access Device / Point of Presence
• Inbound / Outbound permissions
• SIP Options
• Transport type, such as UDP

This is the area where the bulk of service-provider-specific routing and connectivity characteristics are exposed to administration.