Virtual Voice Network
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Demystifying the Migration to SIP Trunking
Read post: Demystifying the Migration to SIP Trunking
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Beyond SIP Trunking: Building a Future-Ready Communication Infrastructure
Read white paper: Beyond SIP Trunking: Building a Future-Ready Communication Infrastructure
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Setec Case Study
Read guide: Setec Case Study
Carrier flexibility and real-time routing control across GTT’s global voice network
Global enterprises want more say over how their voice traffic moves. Virtual Voice Network gives you the control to route calls, integrate your own carriers and expand across regions without building physical infrastructure in every market.
When voice infrastructure gets in the way of the business
Voice routing should be simple. In practice, it rarely is. Most global enterprises manage a patchwork of regional carrier contracts, site-specific hardware and provisioning processes that move at their own pace. Adding a market, adjusting routing or integrating a preferred carrier often triggers a chain of equipment orders and weeks of delay. None of that serves the business.
On top of it, many organizations still own and operate their own Session Border Controllers. Each one needs maintenance, redundancy planning and specialist attention. The capital is locked in hardware. The operational load falls on teams that have higher-priority work to do.
Voice infrastructure built around fixed physical dependencies cannot keep up with how global enterprises actually grow and change. Without a more flexible approach, organizations face a familiar set of problems:
- Adding new sites or markets stalls while provisioning timelines stretch across weeks
- Carrier integration requires significant infrastructure investment at each location
- Owning SBCs locks capital in hardware and shifts the maintenance burden to internal teams
- Inter-office call costs accumulate across regional carrier agreements with no consolidated model
- Routing changes require external involvement, even for simple adjustments
Virtual Voice Network (VVN) removes those constraints. You connect your locations, carriers and cloud phone systems across GTT’s global voice network and gain real-time control over how calls move, without owning the infrastructure that makes it possible.
With Virtual Voice Network, your organization can:
- Integrate third-party carriers for specific regional features or keep existing partner relationships
- Connect globally without standing up physical infrastructure in every market
- Route inter-office calls on-net and eliminate per-call charges between connected sites
- Retire your SBCs and shift to GTT’s globally redundant, fully managed estate
- Change routing, block calls and adjust dial plans in real time through GTT EnvisionDX
What GTT delivers
Bring your own carrier
Connect a third-party carrier for specific local or national voice requirements, or maintain a preferred
partner in a particular region, while routing everything else through GTT’s global network. You choose
the carrier relationships that fit each market. GTT manages the network layer that connects them.
Without GTT
- Regional carrier contracts managed separately with no centralized oversight
- Adding a carrier in a new market requires physical infrastructure and extended provisioning
- Carrier dependencies create routing rigidity with no clean path to adjust
With GTT
- Third-party carriers integrated into a single voice network with centralized management
- Carriers connect through GTT’s network without requiring local infrastructure investment
- Routing policies and carrier selection managed through a single platform in real time
Results
Your carrier strategy becomes an operational advantage rather than a source of complexity.
Free on-net calling
Sites connected to VVN reach other connected GTT locations on-net, regardless of which local
carrier each site uses for external calls. Internal traffic stays on GTT’s network. Per-call charges
between offices disappear.
Without GTT
- Inter-office calls route through regional carriers and accumulate per-call charges
- No visibility into internal call costs by site or region
- Cost reduction requires renegotiating multiple carrier agreements
With GTT
- Connected GTT sites communicate on-net with no per-call charges between them
- Centralized view of call traffic and cost across the full connected estate
- Savings activate automatically as sites connect to the VVN
Results
Inter-office call costs drop as soon as sites connect. The more locations you bring onto VVN, the greater the reduction across your global estate.
Real-time routing control through GTT EnvisionDX
GTT EnvisionDX is a digital gateway and routing engine for the VVN. Design a dedicated dial plan
for your organization, set egress routing trunks and adjust how SIP traffic flows across sites and
carriers, all in real time, from a single interface.
Without GTT
- Routing changes require carrier involvement and introduce delay
- Dial plans are locked to fixed configurations with limited ability to customize
- Blocking or redirecting calls involves manual escalation
With GTT
- Routing adjustments happen in real time through GTT EnvisionDX with no external dependency
- Dedicated dial plans configured to your organization’s routing logic and business rules
- Call blocking and inter-site rerouting controlled directly from the platform
Results
Your team manages its own voice routing without depending on carriers or extended change processes.
SBC replacement
Session Border Controllers are expensive to own, complex to manage and a recurring maintenance
burden. GTT VVN eliminates that overhead. GTT’s intercontinental, fully redundant SBC estate spans
geographically diverse locations across our global network.
Without GTT
- Customer-owned SBCs require capital investment and ongoing maintenance
- In-house SBC management demands specialist staff and extended support windows
- Hardware failure or capacity limits impact voice performance and availability
With GTT
- GTT’s globally redundant SBC estate replaces customer-owned hardware
- GTT manages SBC infrastructure end-to-end as part of the VVN service
- Geographically diverse, fully redundant SBCs maintain availability even when regional issues occur
Results
Organizations reduce capital expenditure, eliminate SBC maintenance overhead and gain access to a more resilient, globally distributed infrastructure than most enterprises could justify building on their own.
How it works
GTT manages the connectivity and routing capabilities that make VVN work so
your team focuses on configuring the policies that suit your business rather than
managing the network underneath them.
1
Site and carrier assessment
We begin by mapping your current voice environment: existing carrier relationships, site locations, cloud phone system integrations and routing requirements. Our team identifies where VVN replaces owned infrastructure, where third-party carriers stay in place and how your dial plan should be structured across regions.
2
Network connection and SBC integration
GTT connects your sites, cloud phone systems and any third-party carriers into the VVN through our globally redundant SBC estate. No new hardware is required on your side. Existing carrier relationships are integrated without disruption to live services.
3
Dial plan configuration
Working with your team, we configure your dedicated dial plan in GTT EnvisionDX, setting egress routing trunks, inter-site routing rules and any call blocking or filtering policies. The configuration reflects how your organization actually routes calls, not a generic template.
4
Go-live and on-net activation
Once configuration is validated, your sites go live on the VVN. Connected locations immediately gain access to on-net calling, real-time routing control and any integrated carrier services. GTT monitors the network from activation forward through our global Network Operations Centers.
5
Ongoing management and adjustment
As your business changes, your routing can change with it. Add new locations, integrate additional carriers, adjust dial plans or expand into new markets, all through GTT EnvisionDX or by working with GTT’s voice specialists. No infrastructure provisioning required on your side.
Why enterprises choose GTT for Virtual Voice Network
Voice infrastructure is only as reliable as the network it runs on. GTT connects over 140,000 customer locations across more than 170 countries, with 80% of customer traffic staying on our top-ranked Tier 1 global backbone. That footprint—backed by 400+ points of presence and a globally diverse SBC estate—means your voice traffic routes with performance and resilience built in.
VVN is designed for enterprises that are already managing complex carrier environments and want a cleaner, more controllable model—not a replacement that forces a full migration before delivering any value. Existing carriers stay connected. Existing services keep running. You gain visibility, control and flexibility from the moment your sites connect.
Discover more in our Voice portfolio
SIP Trunking
Integrating diverse communication capabilities onto a single global platform
Cloud Phone Direct
Global, scalable and high-performing enterprise voice services
Google SIP Link
Use Google desktop features and integrate voice communications with Google SIP Link
Microsoft Teams
We can deliver dedicated SIP trunks to Microsoft Teams services residing in Office 365. As a Tier 1 ISP, GTT peers directly with Microsoft, ensuring the lowest latency connectivity between our voice network and Microsoft Office 365.
Zoom Phone
With Zoom’s BYOC feature, you can use GTT SIP Trunking together with the Zoom Phone cloud. You can enjoy all of the benefits and features of Zoom Phone while benefiting from our global voice solution for outbound calling, as well as new and ported DIDs.
Cisco Webex Calling
Our SIP Trunking service can provide Cloud Connected PSTN (CCP) capabilities for Cisco Webex Calling clients. You can make inbound and outbound telephone calls using telephone numbers assigned by or ported to GTT.
AnywhereNow
Easily incorporate GTT Voice with AnywhereNow cloud-based contact center, natively integrated with Microsoft Teams. You can activate a GTT SIP Trunk group to Microsoft Teams Direct routing and AnywhereNow.
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MPLS
High-performance, secure connectivity for your global enterprise, backed by end-to-end SLAs.
Our Gartner rating
Take control of your global voice routing
Carrier sprawl, hardware overhead and rigid provisioning processes are solvable problems. Virtual Voice Network gives you a cleaner model with carrier flexibility, real-time routing control and a resilient global infrastructure you access without owning.