If you’re familiar with unified communications (UC) you’re probably well aware of the value of rich, multi-modal, presence-driven collaboration tools in enhancing business productivity and speeding decision making within the enterprise. Typically these tools are delivered over a corporate network to users within an organization. The transport protocol used for the delivery is usually SIP, Session Initiation Protocol. Using SIP has enabled organizations to quickly deploy sophisticated tools that truly contribute to successful collaboration and productivity. The SIP protocol has also allowed for services to be deployed to corporations and even end user consumers in a very affordable manner. At least that’s what a service provider pitches when trying to sell their services. In many cases that is true, but sometimes they don’t tell the whole story because in many cases they leave an important component out of the equation at worst or gloss over it at the least. An example is with telephony services delivered over the internet. One of the services that can be delivered using SIP is basic dial tone in the form of trunks from the “telephone company”.
When a company installs an IP data network and connects it to the outside world to deliver their services to their clients and associates they expose themselves to hackers intent on either causing data loss, stealing information or causing general mayhem. The IT staff will typically install a data network firewall to prevent unauthorized access to sensitive company information. When implementing SIP voice from an outside carrier, e.g.; AT&T, Verizon and US Signal just to name a few, they will deliver their service using the internet in many cases. It’s a great way to allow for lots of traffic to occur without the need for the entire infrastructure required to get the “lines” to the corporate PBX. The PBX is still in place and serves the needs of the telephone users the same way it always has but the delivery mechanism from the Telco is different. It’s similar to when all of the lines coming into a company were analog circuits delivered on individual cable pairs and then along came T1 circuits that allowed for 24 trunks to be delivered on a single circuit. SIP trunks represent that next generation of service delivery. Actually they aren’t called trunks anymore in the SIP world, although people still refer to them that way sometimes. They are now referred to as sessions which are nothing more than the number of simultaneous calls that can be active at the same time using a given amount of bandwidth. SIP service is very affordable for a SIP Service Provider (SSP) to install since there really isn’t any infrastructure required at the corporate site from the Telco to make it work. The data packets are routed to the PBX’s IP gateway hardware and the PBX processes the calls just like any other call. The well understood risks of malicious attack from the public Internet make the extension of collaboration beyond the corporate firewalls a risky and difficult undertaking. In other words, a data firewall by itself is not sufficient enough to prevent unauthorized access to the SIP sessions. Data centers need a voice firewall as well. Voice firewalls are referred to as Session Border Controllers. What is a Session Border Controller? How does it work? Why do I need one? Stay tuned! In the next blog we will discuss Session Border Controller and why it is becoming an increasingly important part of your data infrastructure.
