Security is a major concern for any business and when we talk about the VoIP industry, the concern becomes more serious. One of the major question raised by VoIP industry is that Which one is a Better Choice? SBC vs Firewall. All data and media traverse on internet lines, which is why interception of the lines and leakage of data is common. Moreover, the VoIP industry faces major security attacks from hackers and cyber attackers, which include 

  • DOS (Denial of Service) 
  • DDOS (Destructive Denial of Service) 
  • Toll fraud 
  • Call tampering 
  • Vishing 
  • VOMIT (Voice over Misconfigured Internet Telephones) 
  • SPIT (Spam over IP Telephony) 
  • Malware and virus 
  • Call spoofing 
  • And more 

All these threats have made it necessary to implement a reliable security mechanism for VoIP networks and solutions. A session border controller solution and firewall are two popular VoIP security solutions developed by the top VoIP development companies. 

The debate on firewall vs. SBC solution to safeguard a VoIP network has been in the industry since SBC was invented. In this blog post, we will explore more details about both of these options to increase the security of VoIP software, its use, and the complete network in detail. This will give you a better idea of which software is better and recommended for your business. 

Firewall in VoIP 

As the name suggests, the firewall is an obstacle, which is developed and deployed to protect the VoIP solution from external attacks. In the case of a VoIP network when a firewall is installed, it usually creates a hindrance between two different networks. The firewall, technically, is an algorithmic program, which monitors all incoming and outgoing calls, media, and data for security measurement. These inspections are performed based on the protocols and rules defined in the firewall system for VoIP. 

Like a wall, the firewall is a static solution, which is programmed to allow some data and media to enter the VoIP network and stop the rest. Moreover, the firewall can control only layers 2, 3, and 4 of the OSI (Open Systems Interconnection) model. This includes the data link, network, and transport layers.              

SBC in VoIP 

Session border controller solution is a dynamic algorithm and a more advanced version of VoIP security solution. As the name suggests, the SBC system is installed on the border of the VoIP network. It will examine all sessions for security measurements at the border of the network before letting them enter or leave the VoIP network. It is also a program developed by VoIP engineers, which is dynamic in nature. 

Unlike a firewall, SBC software can access all 7 layers of OSI and provide an inspection mechanism to assure the protection of the network at each layer. Thus, along with protection, it can also help in improving the quality of service. 

SBC vs Firewall 

Let’s explore the major aspects to compare both of these security mechanisms for your VoIP network and solution.

Comparison between SBC vs Firewall 

OSI layer 

The common differences between both these VoIP security solutions are quite evident. For example, the firewall can only control 3 layers of the OSI model and a session border controller can control all 7 layers. Thus, at the higher layers of OSI models where voice and video traverse, the firewall has no control, but SBC can control and administer those layers, their security, and their quality. 


The main functionality of both firewall and SBC software is to provide protection against major security threats and cyberattacks. Both of them handle this crucial job based on the algorithms written for this job by programmers. Moreover, a session border controller system also contributes to improving the quality of service by keeping control over call traffic and quality of service. 

A firewall can only block or allow the flow of VoIP traffic and data. On the other hand, SBC can monitor, manage, and control communication sessions in real time for both voice and video data. 


Firewalls are deployed as a gateway in the VoIP network. Technically, firewalls get installed as proxy servers. AnSBC solution gets implemented as a network controller at the border of the VoIP network. It is deployed as a back to back user agent to provide higher control and command over VoIP traffic. 

Topology hiding 

The signaling stream in the VoIP network carries information from the internal network. The network topology details are sensitive and if exposed to hackers or cyber attackers, then they can intercept the network and cause damage. The added security feature, which the session border controller offers over the firewall is topology hiding. This makes sure that even if two different networks exchange data, voice, video, and other forms of media, they cannot check internal and sensitive information of the network. This provides an added layer of security to the users of a feature rich session border controller system. 

Value added functionalities and features 

The firewall does not have any added features or functionalities to offer other than checking the traffic at the stated three OSI layers and allowing or blocking them by opening the wall aka gateway. On the other hand, a session border controller system will have dynamic and useful features to make the whole security solution more effective. 

An SBC in the VoIP network can provide a feature called Codec Transcoding, which is not available in the firewall. This makes a VoIP solution and network compatible with other VoIP networks. Even if SIP variants, codecs, or protocols of two networks are different, these networks can achieve interworking. 

Concluding notes 

Firewall has been in the industry for many years and that is why it is more popular among some VoIP users and engineers. However, the session border controller is an advanced and better version of security mechanisms. In fact, SBC can make a much better difference not only in protecting the VoIP network, infrastructure, and data, but it can also help in achieving multiple other goals. You can improve the quality of service, achieve high compatibility and flexibility between networks, and enjoy higher control over data and packets passing through the network. Thus, a session border controller solution is a much better and superior security system compared to its counterpart. 

If you are interested in safeguarding your VoIP network with a reliable session border controller or custom VoIP security solution like STIR/SHAKEN, then get in touch. 

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