SBC vs Firewall : Which one is a Better Choice?

SBC vs Firewall

Every enterprise needs a robust and effective security mechanism to ensure protection of its network from hackers and cyber attackers. While Firewalls are amongst one of the first security mechanisms, with time and change, SBCs or Session Border Controllers have become a more popular choice. We have created this post to give answers to all your questions regarding SBC vs Firewall or the distinction between a Session Border Controller and a Firewall. Let’s get started.

What is Firewall?

As the term indicates, a firewall is a network security system that typically establishes a barrier between two networks. It monitors and controls all the incoming and outgoing traffic by making use of pre-configured security rules or protocols.

So, basically, a firewall lets certain things come inside the network while keeping others out, just like a security guard. It is a static technology which means firewalls can either open up or shut down interfaces. Also, firewalls have control only over 2nd, 3rd and 4th layers of the OSI model i.e. Data Link Layer, Network Layer and Transport Layer.

FirewallHowever, with constant changes being made in security protocols and system updates, changes get introduced in the 3rd and 4th layer of the OSI model. But the layers 5 to layer 7 remain unchanged as firewalls could not access those. This results in some significant quality issues in real-time communications such as echo in voice and video communication.

When the internet came into existence, it offered very little protection to data. Hackers, cyber attackers and spammers could easily get into a network and steal or misuse data shared over the cloud. Firewalls were introduced to offer network security and they did their job well for a long time, but eventually failed to meet the security requirements of the ever growing networks. As the technologies advanced, so did the tactics of hackers who figured out one way or the other to execute their attacks.

What is Session Border Controller?

SBC or Session Border Controllers are much more advanced when it comes to traffic management. While Firewalls are able to work up to 4 layers of the OSI model of a network, SBCs work all the way up to layer 7. SBCs thus act as a single network management solution that addresses all security and application concerns.


SBCs perform their functions to ensure that phone calls and video systems remain free of any quality issues and thus end users can have a smooth communication experience. Moreover, SBCs ensure that quality of communication remains unaffected even when additional people are conferenced in.

From a security perspective, SBCs make use of AI to detect any malicious parties entering the system. It makes use of static and dynamic ACLs i.e. Access Control Lists to define who is authorized to come in and who is not.

SBC vs Firewall

Now let us understand the difference between SBC and Firewall in terms of various parameters. This will help you select the right one for your business.


Session Border Controllers perform the job of managing and controlling real-time voice and video communication sessions. However, Firewalls can either block or allow the data communication flow.


The implementation of Session Border Controller takes place as a Back-to-Back-User-Agent i.e. B2BUA. On the other hand, Firewalls are implemented as proxy servers.

Media & Signaling

Session Border Controllers are actively involved in the processing of both signaling and media paths. Whereas in case of Firewalls, there is no involvement in the audio/video streams or the RTP media path.

OSI Layers

Session Border Controllers can deal with any layer of the OSI stack. However, Firewalls can only look at traffic on layers 2, 3 & 4 of the OSI model.

Topology Hiding

A major parameter that differentiates SBCs from Firewalls is Topology Hiding. SBCs perform Topology Hiding by removing or hiding basic internal network information from the signaling stream. This is done in order to prevent internal network details being propagated to untrusted networks.

Codec Transcoding

Another way SBCs stands out is their ability to perform interworking between incompatible codecs, protocols and SIP variants. SBCs act as real-time translators throughout each session to ascertain that there is no loss of features.


The main role of Firewalls is to provide security to the network while Session Border Controllers go well beyond the security focus of the firewalls. Besides security, SBCs also ensure that the communication traffic is delivered via the optimum route by using intelligent call routing. By doing so, SBCs ensure QoS i.e. Quality of Service and hence boost customer satisfaction.

It is important to understand the functions of both firewalls and SBCs in controlling traffic and implementing security policies. Only then we can be successful in creating a network design that ensures protection of the vital communication systems as well as providing the desired level of QoS to users.


We all know that security of VoIP networks is important and many of us are under the perception that a Firewall offers almost equal security as that of an SBC. So the contemplation whether one really need to purchase an SBC for securing their business network remains there.

However, with all that we have mentioned above, it is evident that Session Border Controllers offer a clear advantage when it comes to securely deliver reliable, high-quality, IP based interactive communications.



REVE SBC is a robust and scalable Class 4 Softswitch platform designed and developed for communication service providers. It comes with a powerful distributed architecture that ensures network availability and resiliency against cyber threats. Integrated with a real-time billing platform that works on intelligent routing, REVE SBC adds more scalability to your IP wholesale business.

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Read Also

Why Communication Service Providers Need an SBC?

An Overview of Session Border Controller

The Author

Kanika Sharma

Kanika is a versatile researcher, blogger, and author, delving into the world of tech blogs covering Telecommunications and Cyber Security. With a solid engineering background, she turns intricate tech jargons into relatable, real-life stories. Her writing isn't just about words; it's a fusion of detail, intrigue, and relevance to the audience, reflecting her passion for writing and design. Beyond her work, Kanika finds joy in painting, and exploring new places while traveling.