Whether it is about a big corporation or a small office, SBC or Session Border Controllers have become indispensable parts of any network. In this post, we are going to learn and understand all about SBCs - What they are and their role in telecom.
A session border controller is hardware or software-based technology that controls communication between two end devices over a network. Let’s break the terminology into three simple parts to understand it more easily:
Session - It is the communication that happens between two parties. It can be in the form of a phone call where each call is made up of two streams that together make a session. Here the SBC controls and supports the flow of sessions.
Border- As the term indicates, it is the boundary between one part of a network and the other. The flow of data from one network to another is managed by SBC.
Controller - It is that part of the SBC that is responsible for controlling and influencing data streams and sessions.
Functions of a Session Border Controller
Protection and Security of the Network
SBCs work effectively to prevent various types of attacks including Denial-of-Service Attacks, Spoofing Attacks, Toll Fraud, etc. SBCs do so by hiding the network architecture and making it difficult for cyber attackers to get into the sensitive parts of the network. Also, SBCs implement state-of-the-art encryption algorithms to ensure that communication is not being intercepted or tampered with.
Session Traffic Surveillance
We can imagine SBCs as the gatekeepers to VoIP networks whether it is an enterprise’s or a service provider’s network. Here Session Admission Control is the process used by SBCs to determine who has the authorization to access the network and who does not.
Offers a Smooth Experience
Since different VoIP solutions use different audio codecs it demands protocol translation for communications to happen successfully. SBCs enable the translation of SIP variants between devices and thus offer a smooth experience in terms of interworking between different networks.
Enables SIP Trunking
In SIP trunking, the connectivity is between an on-premise phone system and a Public Switched Telephone Network. An SBC monitors all sessions that cross the internal network and the external network, determining where each session should be routed. While performing this job, it considers various factors like assigned priorities, bandwidth usage, network policies, etc.
Role of SBCs in Telecom Security
Before we understand the role of session border controllers in securing the telecom networks, let us take a look at some of the major attacks that happen in the telecom domain:
Registration Storms: It happens when multiple devices, say hundreds or thousands, try to register with a SIP server of a VoIP network at the same time.
Spoofing: Here the attacker modifies or disguises his identity on the network to gain an illegitimate advantage. It can be a change in an email address, phone number, website URL, display name, etc.
Denial-of-Service Attack: DoS and DDoS attacks are one of the most frequent types of attacks that happen in the industry. Here the attacker floods the network with hundreds and thousands of requests in order to slow down or even cause a complete shutdown of the entire system.
Service Theft: Here the attacker gains access to a VoIP system that is inadequately secured. By doing so, the attacker uses services and resources without paying for them. The bill is paid by the enterprises or service providers as they realize this later.
Stop Telecom Attacks with SBC
It is clear that malicious and fraudulent attacks are on a continuous rise. But such attacks can be easily prevented or managed by deploying Session Border Controller at the required network perimeters. An SBC does the following to keep a check on telecom attacks and frauds.
● It acts as a B2BUA i.e. Back Back User Agent which makes all the signal and media traffic run through the SBC and thus hides the topology of the network. Thus, the critical or vulnerable elements of the network such as IP addresses remain hidden and secure.
● By implementing media and signaling encryption, an SBC ensures that no malicious party can get access to VoIP calls and video conferences, as also all other types of communications.
● SBC performs monitoring of incoming calls and requests to identify and block abusers if any. It maintains certain lists such as whitelists, blacklists, and grey lists.
If your VoIP network is still not equipped with a Session Border Controller, then it’s high time you get one to safeguard from cyber-attacks and fraud.
