How Session Border Controller Can Keep Your VoIP Network Secure

Session Border Controller

Businesses are switching over to TCP and IP based communications due to obvious benefits and this have led to rising of VoIP service providers. These service providers tie into telecom carriers at one end and to business users at the other end. It is sufficient to have class 4 and class 5 soft switches to get this operation going but then there crops up the question of security, so vital for business communication. Existing anti-virus solutions or firewalls may not be sufficient to address security concerns.

It is all in the packets

Voice and audio data are converted to packets that travel over the internet. These packets can be tapped into and the ports that they travel through can be opened by hackers. They can then listen in or launch malicious attacks. Packets can carry identifying data about origin and destination and that makes company communications quite vulnerable. Simple firewalls with single routers can take care of local SIP connection but there is more to data packets that calls for a more sophisticated solution that only a proper session border controller can provide.

Typical firewalls only address network data. SBC focuses on SIP traffic and audio/video streams with emphasis on security in addition to other functions that enhance VoIP services.

Hardware or software

Some advocate the use of hardware-based session border controller configuration. While this may have its plus points there are cons too such as cost and upgrade limitation. Software SBC VoIP solutions integrate much better with class 4 and class 5 while offering a much easier and less expensive upgrade path. In addition, one can include customized billing and monitoring, features that VoIP services find desirable to have. It can take care of virtually all security aspects besides offering other benefits.

Session Border Controller
Session Border Controller



A telecom carrier may have an SBC at his end but it is not sufficient. Ideally, SBC should be part of the VoIP chain at the Service Provider’s end as well as at the user end. For VoIP service, SBC is indispensable to prevent denial of service and distributed denial of service attacks that can simply bring services to a standstill. Smart SBCs have a feature that monitors and manage IP traffic and can issue an alert in case of the suspicious activity that a typical DoS attack indicates enabling administrators to take timely action.


Business clients need absolutely confidentiality of conversations that PSTN lines assure but which a VoIP network cannot assure unless an SBC is in place. SBC uses transport layer security to secure packets and it also hides network topology. Eavesdropping is not possible and hackers cannot decipher network topology. SBC  hides topology, adding a further layer of security. SBC typically apply TLS to packets and implement secure real-time transport protocol to prevent eavesdropping.

Toll frauds

Frauds can happen from within a client company when an employee makes use of the network for personal purposes or hackers can make use of the account to make free calls. VoIP services can lose huge amounts due to toll fraud and if it happens to a client account they may lose that client as well. SBC configuration prevents different ways to prevent toll fraud as well as the ability to detect attempts and issue alerts. It keeps customers happy and VoIP service providers have loyal customers.

With the right SBC VOIP solutions in place, security is as high as it can get to assure peace of mind for VoIP service providers and their clients. Then, there are other benefits too that SBCs bring in their wake.

Interoperability, media transcoding, NAT

While it takes care of security much better than firewalls can, SBCs also manage IP traffic in a way that results in fewer dropped packets. It also takes care of scaling according to traffic. Media transcoding is not a big thing but it does matter when calls originate or terminate across various geographical regions where people may be using various different codecs. SBC delivers smooth, jitter-free audio quality regardless of bandwidth. Interoperability between various devices does not pose a problem. The system can pay back for itself over time since it has intelligent least cost routing features that save money for the VoIP service provider and enhances revenue. Administrators can assign policies and rights to authenticate users. The billing feature tracks each account separately and does so without errors. One can even include direct payment facility within the SBC.

To sum it up, SBC is just indispensable in today’s environment where security is a vital concern in business communication. That it also includes least cost routing, monitoring, and analytics, media transcoding, interoperability, billing, and NAT is an added bonus. Software SBCs are quite flexible in the way they can be implemented into various existing VoIP networks and class 4/5 switches so they should be the preferred option and, if you can get a hosted solution, it is so much better.

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