Experiences of a Telecommunication Engineer.
My Special thanks go to Sri Lanka Telecom PLC & Etisalat Lanka Pvt Ltd for providing me with a better Training & Working Experience.
Department of Electronic & Telecommunication Engineering, University of Moratuwa.
NOTE: My posts may include some vendor specific names.
Why we can’t use a normal Firewall instead of a SBC
Normal internet browsing traffic consist of comparably large in packet size and lesser number of packets (i.e. lesser number of headers). A typical firewall will inspect and check the headers. VoIP traffic is different from normal internet browsing traffic. VoIP traffic consists of large number of smaller (smaller in length of the packet) packets which comes in bursts. IP packet headers are more or less the same. If we are using a Firewall in VoIP, it has to process large amount of headers. Hence need more processing in a VoIP (That's why we have to introduce a SBC instead of a normal Firewall). On the other hand in a normal firewall, provided security is low as well. Therefore we use an SBC instead of Firewall. Security level of a SBC is very high.