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Difference Between Class 4 and Class 5 Softswitch

  • October 4, 2022

Difference Between Class 4 and Class 5 Softswitch

VoIP has made communication cheap and seamless for end users and businesses. There are so many amazing IP telephony solutions that make our life easier. The class 4 Softswitch and class 5 Softswitch are the two most popular VoIP solutions that are widely used.  

In general, this VoIP software is called a VoIP Softswitch solution, which transforms the manual process of switching a call by an operator using a switchboard into the automated one. Softswitch is made of two words Software and Switchboard. It is a focal point of an IP telephony network in any VoIP business as it centralizes the process of routing calls to reach the destination. The VoIP Softswitch can route the call to a public network or a private network depending on the requirement of the call.  

How does a VoIP Softswitch work? 

Usually, a VoIP Softswitch solution gets connected with a media gateway controller, media gateway, signaling gateway, TDM circuit, and IP lines to provide a complete network of call routing. It can route SIP to SIP or SIP to VoIP calls and vice versa. 

It means this VoIP solution is not restricted to providing communication services only between VoIP devices or SIP numbers. It can, in fact, enable PSTN to VoIP calling as well. 

The best VoIP development companies develop the most advanced, robust, feature rich, secured, and scalable VoIP Softswitch software solutions. Depending on the functional model, features, and multiple other factors, this solution can be divided into three different categories: 

  1. Class 4 Softswitch   
  2. Class 5 Softswitch and 
  3. Hybrid Softswitch 

There are also less known solutions available, which are class 1 to class 3 Softswitch solutions.  

As the class 4 Softswitch software and class 5 Softswitch software are directly referred to and are the most popular ones, let’s compare these two major VoIP Softswitch solutions. 

Defining Factor

Class 4 SoftSwitch

Class 5 SoftSwitch


It is also known as a wholesale Softswitch because it routes massive call volume from carrier to carrier. 

It is also known as a retail Softswitch solution because it routes local calls from end user to end user. Alternatively, it may route calls to the class 4 switch to reach the international destination. 

Services area

  • It routes calls at a larger scale and serves at an international level. 

  • A majority of times, it routes calls to long distance destinations.

  • It usually routes calls across countries.   

  • It routes calls at a smaller scale and serves at the local level. 

  • It routes calls to a short distance. 

  • It can route calls within companies, cities, or states. In some cases, with the help of a robust VoIP development company or smart telephony platform provider, it can sometimes route calls within small countries.  

Call routing vicinity 

  • It can route calls across multiple IP networks. 

  • It routes calls across IP or SIP networks and PSTN networks. 


  • It connects carriers and caters to carriers.  

  • Usually, VoIP service providers, internet telephony service providers, telco companies, operators, and similar VoIP business owners use this Softswitch solution. List Item 2

  • It connects end users and caters to the end users. In most cases, these are business people that use a VoIP calling system. 

  • It is used by enterprises, businesses, and end users. 

Call traffic type 

The class 4 Softswitch solution routes massive call volume and often it is wholesale traffic. It routes all types of media to the defined destination. 

It routes a small chunk and often a few calls. It can also transit different media types. 

Role in a VoIP telephone network

To enable long distance calling, it sits in the central location of a telephone exchange and connects local carriers, class 5 Softswitch solutions, etc. 

To enable peer to peer communication, this VoIP Softswitch solution sits at the local network of a business. It can be connected with the class 4 Softswitch software to enable long distance calling for end users. 

Concurrent call capacity 

It can handle massive call traffic and routes thousands of calls per second (CPS).  

It can handle tens or a few hundred calls per second (CPS). 

Business usage 

A class 4 Softswitch solution is used to run long distance VoIP services to provide wholesale call traversal services to telecom companies and service providers. 

The retail Softswitch solution is used to cater to both VoIP service providers and end users. It can be used to offer and leverage a business phone system working on the phenomenon of IP telephony.  

DID usage

  • It does not use DID based call routing. 

  • It uses DID based call routing. 

Tenant support 

Usually, this Softswitch solution does not support tenant creation. It is an independent solution. 

A retail Softswitch solution can be a single tenant or multi tenant system. 

VoIP billing 

An extensive VoIP billing solution integrated into wholesale Softswitch is a must to automate invoicing and billing process. 

If it supports multi tenancy, then it will need a VoIP billing solution. For a single tenant system, VoIP billing might not be needed. 

Key features 

It has a few features compared to the class 5 Softswitch solution

  • Protocol support and conversion 

  • Transcoding 

  • Secure firewall 

  • Session border controller (SBC) 

  • Different call routing rules like: 

  • Least cost routing (LCR) 

  • Hybrid call routing 

  • Prefix based call routing  

  • Priority based routing 

  • Lossless routing 

  • Cost based call routing 

  • CLI and Non-CLI routing 

It has several features compared to the wholesale Softswitch as it is used to provide communication and collaboration services to the end users and businesses: 

  • Authentication, authorization, and accountability 

  • Analog to digital conversion and vice versa  

  • Codec transcoding 

  • Media conversion  

  • IVR 

  • Call forwarding  

  • Call transfer 

  • Call mute and un-mute 

  • Call hold and pickup 

  • Callback scheduling 

  • Call queue 

  • Call routing 

  • Ring office 

  • Time based call routing 

  • Voicemail support  

  • Reports 

  • And Many More

The class 4 Softswitch and class 5 Softswitch are completely different and serve different purposes. However, together they complete the VoIP telephony network. 

If you are interested in any of these VoIP Softswitch solutions