SIP Trunking and the Role of the Enterprise SBC

SIP Trunking and the Role of the Enterprise SBC

a Tango Networks ebriefing SIP trunks offer companies of all sizes the opportunity to improve and simplify their communications network while reducing costs. As these companies leave their legacy voice communications systems behind, SIP, the Session Initiation Protocol, is the direction in which they are heading. SIP is the primary building block for UC (unified communications) infrastructure, and SIP trunks offer many advantages: reduced costs, dynamic highly scalable architecture, and high reliability. However, SIP trunks do create new security challenges. We'll get to that later, but first it helps to take a minute to better understand the concept of SIP trunking. SIP has been around for a couple of decades now, but only started gaining real traction in the last half dozen years or so, as more and more companies migrated away from older communications systems. SIP offered the promise of cost savings by changing the way we think of trunks and eliminating the need to buy trunks from the local telephone company for every one of your company's locations. SIP was also positioned as the gateway to UC, but because the ROI-type benefits were harder to quantify at the time, the hard dollar savings of SIP trunking became the justification of the migration. 2

SIP Trunking and the Role of the Enterprise SBC Important to note is that SIP trunks aren't really trunks, at least not in a traditional, physical sense. SIP trunks are allocations of capacity set aside to carry voice calls over a data circuit. As a result, SIP trunking upended the traditional telecom model, which involved buying PBX trunks at every location. It is a simplified architecture that has clearly become the preferred method for voice communications. With SIP trunks, your organization needs only a data connection from your service provider. All calls ride on your company's internal data network to the data center, eliminating the need for your company to work directly with local telcos at each company site. The Role of the SBC The session border controller SBC controls the signaling and media streams involved in SIP as each communication session, or call, is established, controlled and maintained for the duration of the session, and then terminated when the session concludes. The word "border" is in the name because it serves as the point of demarcation between the enterprise network and the service provider's network. As such, the SBC secures communication between the service provider network and the company network via techniques such as network address translation, topology hiding, necessary SIP normalization, transcoding, and inter- 3

a Tango Networks ebriefing working between IPv4 and IPv6 Internet addresses. It is a quality of service tool and one that allows a wide range of various media services. While SBCs have traditionally been hardware-based and physically located in specific sites, softwarebased systems offer the promise of additional cost savings as well as increased flexibility. This enables enterprises to more readily deploy their own SBCs and communication infrastructure. There are some compelling reasons for an enterprise to embrace this strategy. Security: The service provider's SBC is deployed to protect the service provider s network, not yours. When deploying your own SBC, you are in control of your security. The SBC allows you to freely up- grade your infrastructure, because it will act as the back-to-back-user-agent to normalize any SIP anomalies between your service provider's network and your UC network. With your SBC, only properly formatted SIP messages enter your network and the SBC will work with your existing security infrastructure to keep out viruses, hackers, and attacks. The SBC is a critical element in your layered security architecture when deploying SIP. Call control: Because only your company really knows the details about the bandwidth configuration and usage of your network, an enterprise SBC can take care of call admission control. For example, if the a call requires high definition presentation and therefore high bandwidth, the SBC can ensure that sufficient 4

SIP Trunking and the Role of the Enterprise SBC bandwidth is dedicated to maintain a high level of call quality. Network address translation: IPv6 is becoming the standard as IPv4 addresses are being consumed. But nearly every enterprise still works with IPv4 addresses. They use many private addresses but only a small number of public addresses, which requires translation. With IP addresses embedded inside SIP messages, the Tango Networks SBC can translate IPv6 to IPv4 addresses and private IP addresses for maximum flexibility. Call recording: With legacy systems, it required special hardware to tap into a trunk and split the audio into two different paths in order to enable call recording. SBCs accomplish this in software, making them the ideal tool for enabling recording, whether that recording is required for regulatory purposes or is a company policy or preference. System adaptations: SBCs offer SIP adaptation tools that assure that SIP messages are compatible between and among PBXs and unified communications call servers from multiple vendors and service provider networks. Transposing, translation: The SBC acts as the translation point in architectures where there are multiple elements that need to communicate but lack a common method to do so. One example would be enabling different codecs on the public side and the private side of the SBC. 5

a Tango Networks ebriefing Routing: In environments with communications systems and applications from multiple vendors, an SBC can route SIP sessions between them to centralize resources, eliminate duplication and reduce operational costs. With network security paramount in a SIP trunking environment, the SBC adds to the layers of protection. The SBC provides session level, or SIP layer, security. Architecturally, this approach lets the SBC perform those functions that it does best, while trusting data network security to the equipment that is best suited for that function. The Tango Networks SBC and Application Server connects any PBX, call server, or UC platform to SIP-based service providers. As a software-only, NFV solution, it is completely customizable and can be quickly and cost-effectively deployed in your data center or on premises at remote sites. Tango Networks' SBC and Application Server The Tango Networks SBC and Application Server is a cost-effective software solution that brings a new level of security, simplicity, and functionality to SIP trunking. 6

SIP Trunking and the Role of the Enterprise SBC Tango Networks SBC and Application Server, is a software solution that simplifies network administration. It reduces the number of proprietary hardware components in your network as it improves the efficiency of scaling and geographic redundancy. The same software platform that supports SIP trunking also enables other Tango Networks Enterprise Mobility applications, such as call recording, business continuity, and mobile unified communications. It features interoperability across call server/uc vendors and service providers, and is SIPConnect compatible. The Tango Networks SBC and Application Server is easily deployed, with web portal-based, one-click provisioning. It offers centralized provisioning and management, disaster recovery and failover routing, least cost routing, and a centralized enterprise dial plan. 7