Most VoIP services may assume that setting up class 4 and class 5 softswitches are all that they need to run their business. These two are sufficient but security is a prime consideration and for that, the normal firewall is simply insufficient. A session border controller in the network at both ends is ideal and recommended.
Why session border controller is indispensable
VoIP is IP based traffic over an open network system where any IP address can connect to another and therein lies a vulnerability that is open to exploitation. It is easy to eavesdrop or inject malware, both of which are harmful to VoIP service providers and their business clients. A denial of service attack may result in loss of communications. Hackers can search for and find ports that are open, something that the SBC hides as part of its security feature. Then again toll fraud is another occurrence in which hackers may hairpin calls and spoof service providers. In the absence of a suitable session border controller any hacker with malintent can intrude and gain access and make calls as a local extension, mimic IP address, user names and passwords and play havoc with identity theft. They may even start spamming. Without an SBC in place it is open season for hackers. VoIP service providers can see disruption of services, loss of reputation and loss of customers. These are the various “whys” for the need of a tightly integrated software SBC solution in the network.
How SBC keeps VoIP secure
Smart SBC solutions for developers who infuse a degree of AI into the solution help the session border controller to monitor incoming and outgoing traffic and block or allow access. Suspicious traffic can lead to alerts to administrators. SBCs typically use B2BUA technology to handle SIP traffic.
Normal firewalls have issues with NAT but the SBC sits as a trusted VoIP firewall that allows network address translation (NAT), topology hiding and IP address cloaking. Besides, port forwards are not necessary.
SBCs with smart intrusion detection systems can detect attempts at policy violation or malicious activity and automatically terminate connection while issuing an alert.
SBC solutions for VoIP security handle access control lists much better and define with precision the acceptable IP address even as they monitor activities. Most attacks occur at the ACL, which is a TCP/IP layer and vulnerable. SBC handles ACL along with peering and authentication before a call is processed.
The SBC also handles call admission control and restricts traffic in case of a security breach. They make sure that call rates are never exceeded and this saves precious revenue of carriers and service providers.
SBC also provide better security by encrypting all SIP signals so, even if someone should eavesdrop downstream, he just cannot decipher or decode media stream.
While interoperability and media transcoding may not fall within the security features ambit, SBCs do handle these parts much better and make for a more seamless communication experience across diverse networks. Malformed SIP packets are restructured automatically, further aiding in the user experience. Then there are other features like flexible routing, least cost routing, dial plans and others that further contribute to making a session border controller an indispensable part of the VoIP network. Better still, billing, accounting and monitoring can be layered into the SBC, independent of the class 4 softswitch.