If you operate a TDM network you know, the time is coming… Your equipment is aging, your technicians are retiring, and the spares are sparse.  With Ribbon's call controllers, you can accelerate your network modernization. 

Ribbon acquired Nortel's carrier business in 2010. Our people have decades of in-depth experience deploying and migrating DMS and CS 2000 offices. Over the past decade, our professional services teams have replaced over 30 different switch types, all while keeping the regulators happy and without affecting subscribers.  Ribbon's solutions will integrate into existing front and back office systems, saving providers time and money in the transformation process. It's no surprise that Tier 1, Tier 2, and Tier 3 service providers globally rely on Ribbon to transform their network.

Ribbon has successfully transformed Mobile, Local Exchange Carriers (LECs), Competitive Local Exchange Carriers (CLECs), Rural providers, MSOs, IPX providers, UCaaS providers, including;

  • Over 4,000 End Offices Migrated
  • Over 55M Ports (lines and trunks) Migrated

Ribbon's Call Controllers and Application Server use the latest virtualized software and COTS hardware to enable providers to dramatically shrink their carbon footprint, shrink infrastructure costs, and simplify ongoing support. With Ribbon, moving to modern software doesn't force providers to rip and replace their last mile. Ribbon can help providers transition their legacy last mile, at their own pace, with the industry's most complete and fully integrated gateway portfolio. Of course, the same Ribbon solutions support full VoIP implementations to maximize RoI.

Ribbon enables service providers to deliver mobile, fixed, long-distance, business, and consumer voice services. Our call controllers lead the global market in transforming networks and are the basis for core services and switching infrastructure for millions of users worldwide.

Call Controller Products


C3 Call Controller

Multi-application virtual call server and media resource/media gateway controller, deployed by leading communications service providers

C3 Datasheet


C15 Call Controller

Enable IP and legacy services for Class 5 replacement, including HD voice, Centrex, web portal, mobility, video calling, & call logging.

C15 Datasheet


C20 Call Controller

Provides call and session control, network connectivity, switching, signaling, protocol interworking, voice and communications.

C20 Datasheet

Experts in Network Transformation

Ribbon is the Market Leader in Class 4/5 Transformation Services and We Have the People, Process, Tools, and Capabilities to Get the Job Right.

Over 4000 Offices Collapsed


Over 55M Ports MIgrated


Solutions Migration to Virtualization and NFV


Over 30 Different Switch Types Migrated

End-to-End Proven Class 4 and 5 Transformation Solutions & Services


Virtualizing Your Core Networks

Virtualized Access and Media Gateway Control Function Deployment Options For Service Providers

Download Analytics for C20 Solution Brief

Download our Virtual C20 Datasheet

The C20 simplifies complex architectures delivering voice and multimedia services that enable new services and revenue growth

Call Controller Products and Solutions

Ribbon is the market leader in Class 4/5 transformation services with three state-of-the-art and widely deployed carrier class platforms and software


Services C20 Call Controller C3 Call Controller C15 Call Controller
Applications Class 4 and Class 5 Class 4 Class 4 and Class 5
Server Provider Type Tier 1, 2, and 3 Tier 1 and 2 Tier 3
Deployment Options Virtualized Virtualized Appliance
BHCA Up to 6 Million 1 Million (Per Server Pair) 250,000
CS2000 Upgrade *    
DMS, EWSD, 5ESS, Collapse, Migrate and Replacement *   *
Local and Tandem * * *
IPX / Transcoding   *  
VoLTE   *  
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