You are here


Softswitches are carrier-class servers that control voice phone calls across circuit- and packet-switched networks, which promise to support intriguing new services by dint of their open application programming interfaces for service software. The attraction softswitches hold is that they cost about a tenth of regular local phone switches, take up much less space, and have open APIs that enable third-party vendors to write complex services the switches control. They also enable completion of calls between circuit-switched and packet networks, enabling carriers to use a single packet backbone for voice and data traffic.

Switching lies at the core of all telecommunications networks, allowing efficient point-to-point communications without direct connections between every node. The Softswitch is a new software-based switching solution that runs on standard hardware to supplement or replace central office switching functions. Softswitches execute the same functions as traditional switches and are completely transparent to end-users. Telecommunications companies are embracing softswiches because they are functionally equivalent to conventional phone switches, only better, faster, and cheaper.

One characteristic of Softswitches is their open architecture, which provides great flexibility for carriers to develop custom solutions based on best-of-breed hardware and software components. Softswitches also tend to be modular, smaller, and less expensive than their conventional switching counterparts. This modularity makes scaling easy, critical when telephony markets and technologies can change overnight. As with conventional switches, high availability and reliability remain the top priority. Softswitches must also maintain compatibility with PSTN networks (Public Switching Telephone Network) and compliance with switching standards.

Softswitches provide several advantages over traditional switching alternatives. They reduce the cost of providing service by using less expensive IP networks. They allow carriers to differentiate their offerings through value-added services, often by simply adding a new server that delivers the desired functionality. Softswitches also allow telecommunications companies to leverage their existing investment in switching, preserve interoperability with PSTN networks, and assure a smooth transition to packet-based IP technology.


• Class 4 Softswitch
Tandem offload / long-haul TDM
Outgrown switch and/or network capacity
Unified backbone network and management 

• Class 5 Softswitch
End-of-life switch replacement
Broadband voice access
Augmenting / migrating existing Class 5 infrastructure
Demanding service / feature set 

Softswitch Benifits:

Reduce Costs

  • Manage networks more efficiently

  • Reduce costs of handling calls

  • Boost capacity of existing lines by offloading data to IP networks

Improve Service

  • Differentiate service through value-added offerings

  • Roll out new services more quickly

  • Provide end users capability to maintain their own service preferences

Facilitate Migration to IP Networks

  • Leverage existing databases

  • Evolve networks and services through a distributed architecture

  • Allow for easy expansion


Softswitch Resources:

Ericsson: Softswith in mobile networks

Softswitch Theory and Practice

Sun: Softswitch Whitepaper / Tutorial

Wikipedia Softswitch