Softswitch
What Is a Softswitch?
A softswitch is software that controls how calls are set up, routed and ended in a voice network. It does the job of a traditional hardware telephone exchange, but runs on general-purpose servers and handles calls over IP. Service providers use softswitches to route traffic between carriers and to deliver calling features to business and residential subscribers.
How does a softswitch work?
A softswitch separates call control from the voice traffic itself. The call-control layer determines how a call is established, routed and managed, while separate media resources and IP networks may carry or process the audio. Its main parts are:
Call agent (call control): the software that makes routing decisions and applies features
Media gateways: devices that convert voice between IP and traditional phone networks
Signaling: SIP for IP calls, and SS7 links or gateways where the network connects to the traditional phone system
Supporting systems: billing records, provisioning, number databases and admin portals
Class 4 vs. Class 5 softswitch
Class 4 softswitch | Class 5 softswitch | |
|---|---|---|
Main job | Routes transit traffic between carriers | Serves end subscribers |
Typical traffic | High-volume long-distance and wholesale calls | Local calling for businesses and households |
Features | Routing, least-cost routing, trunking | Voicemail, call forwarding, hunt groups, auto attendants, hosted PBX |
Typical users | Wholesale carriers and long-distance providers | CLECs, hosted voice and UCaaS providers |
Many service provider migrations involve the subscriber-facing Class 5 layer, because that is where customers' users, features and call flows live.
Softswitch vs. PBX vs. UCaaS platform
A PBX serves the phones of one organization. A Class 5 softswitch serves many customers at once from a provider's network. UCaaS platforms build on the same call control and add multi-tenant management, apps, video and integrations. Platforms providers use for hosted voice, such as Metaswitch, Cisco BroadWorks and NetSapiens, are often discussed under the softswitch category, though each is built differently.
What does migrating off a softswitch involve?
Moving customers from one softswitch platform to another is more than a data export. Each customer environment needs to be rebuilt and confirmed on the destination platform:
Subscribers and accounts: users, extensions and permissions
Features and call flows: auto attendants, hunt groups, voicemail and forwarding rules, checked for feature parity
Dial plans and routing: local rules, trunks and inbound number routing
Devices: phone models, firmware and provisioning configurations
Numbers: re-routing or number porting, timed with each cutover wave
Providers also migrate to consolidate. Running more than one softswitch platform, often after an acquisition, can mean duplicate integrations, billing workflows and operational knowledge. See telecom platform consolidation.
Vox Matic helps service providers migrate customers from platforms such as Metaswitch and BroadWorks to NetSapiens, using Otto™ to automate repeatable extraction, transformation and provisioning work. Fuse.Cloud estimated that its BroadWorks-to-NetSapiens migration would take approximately 18 months using a manual approach. Working with Vox Matic, it was completed in approximately six months. Results vary according to source environment, scope and customer complexity. Read the case study.
Frequently asked questions
Is Metaswitch a softswitch?
Yes. Metaswitch provides Class 5 softswitch and calling feature platforms used by many service providers for business and residential calling.
Is a softswitch the same as a SIP server?
Not exactly. Many softswitches use SIP, but a softswitch also handles routing logic, features, billing records and connections to the traditional phone network.
Why do providers migrate from one softswitch to another?
Common reasons include consolidating platforms after an acquisition, standardizing on one platform for all customers and moving to a platform with the features and integrations they want to offer.
Related terms
Planning a move from Metaswitch or BroadWorks?
NetSapiens is a trademark of Crexendo, Inc. Metaswitch and BroadWorks are trademarks of their respective owners. Otto™ and Forge™ are trademarks of Vox Matic. Vox Matic is an independent migration services provider. References to third-party products are for identification and interoperability purposes only and do not imply endorsement, except where an authorized partnership is expressly identified.