Real Time Communications Featured Article

From SIP Trunking to SBC as a Service

July 10, 2015

Running calls between IP-PBXs and telephony providers through SIP trunking, despite the difficulties over the years, has proven to be a powerful tool for businesses.  In the beginning, businesses needed to operate and configure both the baseline Internet connection and a session border controller (SBC) to provide transcoding between different media and SIP types and provide the all-important security "border" between the corporate network and from the rest of the world. As network function virtualization (NFV) is rolled out in carrier networks , service providers are now able to deliver SBC as a service.  What's not to like?

Consider the issues of operating a stand-alone SBC.  You have to either buy a dedicated appliance or, as more often the case these days, find space on a server to run a virtualized instance of a SBC.  The former approach is going to be more expensive, but requires less engineering provisioning forethought than trying to juggle virtualized sessions on a larger server with other tasks on it.

Once you figure out the location for your on-premise SBC, either physically or virtually, and write the checks to make it happen, the next step is carving out IT staff time to load the software, configure it, and then test and continue to monitor it, along with applying software updates, patches, and configuration changes as needed.  The ongoing overhead for maintaining the SBC alone might make it worthwhile to consider purchasing an SBC as a service.


The financial advantages for purchasing SBC as a service as part of a package from your service provider are pretty obvious, but there are a number of operational benefits as well.  Your IT budget doesn't take a big capital hit up front in purchasing a SBC, for one thing.  Costs for SBC operations can be rolled into operating expense as a part of the overall broadband and voice budgets, and you can get some (admittedly meager) power savings if you had planned to use a dedicated appliance.

However, the two biggest advantages for SBC as a service are in terms of scalability and security.  NFV enables the creating of an SBC in a matter of minutes.  Scaling SBC services up or down is as easy as a phone call, email, or website request to the service provider.  For businesses that are seasonal or otherwise deal with surge events, adding more inbound capacity becomes a necessity in managing costs and not having unutilized resources. 

Transcoding and encryption, both compute-intensive tasks, can be easily handed on-demand by a SBC service.  The service provider has a larger dedicated pool of distributed servers available for heavy lifting and can apply that resource as needed by the business.

Since the SBC is run as a service, there are dedicated staff at the service provider whose sole job is to make sure the SBC is tightly and efficiently run.   Malicious events, such as a distributed denial of service (DDos) attack, are quickly caught in progress through network monitoring and can be countered through using NFV to add more "cloud power" for SBC processing as needed.   The service provider should also have a better view of inbound attacks and be able to apply measures further upstream from the customer to defend and defeat DDoS and other malicious events than an individual enterprise.

If that those reasons aren't enough, the service provider also handles all software upgrades and maintenance.  IT staff can focus on other issues rather than concentration on SBC operations.

Edited by Stefania Viscusi

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