Making OCS Smarter

The Gartner Group recently concluded in a study on UC technologies that interoperability is critical to a UC solution. As I watch emerging technologies move to the mainstream, I could not agree more. I read the Gartner report at about the same time I read an NET white paper on Demarcation Device benefits with Microsoft’s OCS – and was struck by the clarity of this interoperability message.

Anybody considering Microsoft OCS will understand Session Initiation Protocol (SIP). SIP trunking continues to increase in popularity, particularly within OCS environments, for several reasons. First and foremost is cost savings; SIP trunks tend to run 50-70% less than TDM trunks. This is partly due to the power of one – that is, SIP trunks can be added incrementally in units of one rather than 24 or 23. Additionally, SIP trunks have lower overall costs, particularly with domestic and international long distance. The savings associated with SIP are often a significant part of the OCS business justification. Another key benefit of SIP is the ability to cost effectively centralize trunking which offers lower costs and simplified administration at remote locations. Plus SIP trunks can be rerouted or different locations quickly should the need occur. 

SIP is a fairly loose "standard." Unlike in T1 implementations where the incompatibility could be resolved by tweaking various options, nuances to the carrier's implementation could completely prohibit interoperability. This is why equipment support for most SIP implementations is restricted to approved carriers; a necessary reduction in choices in the name of supportability.

One solution is to use a demarcation gateway in the mix. NET is a Microsoft partner with OCS certified gateways can significantly strengthen the OCS implementation without messing up the ROI or supportability. This is an important concept - increasing the utility of UC without risking the supportability can require a multi-vendor approach. To better understand this requires a brief introduction to the OCS architecture.

In OCS, multiple servers play various roles. It is the "Mediation Server" that connects the OCS environment to the Internet telephone service provider (ITSP). The mediation server translates the OCS proprietary Real Time (RT) audio codec (used within OCS deployments) to the G.711 codec (commonly used in SIP networks). The NET VX Series gateways tightly integrate with the mediation servers. This effectively places a hardened appliance in front of the general purpose server decreasing vulnerabilities to external threats. 

This gets back to the interoperability issue and how the use of a demarcation gateway can help. In the Gartner Group paper, Bern Elliot and Steve Blood of Gartner wrote, “No vendor product adequately addresses all of an enterprises’ UC needs. As a result, planners should not expect their UC requirements to be met by one vendor’s products.” By inserting a demarcation gateway that is endorsed by Microsoft into an OCS environment, the user can significantly increase their capabilities and deployment options. For example, the OCS mediation server can translate between the RT Codec and G.711 codec. With the NET gateway, additional codecs can be selected including the G.729 (compressed) or G.722 (wideband) codecs, or even T.38 (for fax support). This is adding codec support, not translations - the gateways perform direct translation to/from RT Audio.

Currently, of the many ITSPs (also known as SIP providers) Microsoft OCS supports just three currently (Sprint, Interoute, and Global Crossing). With NET, the list of supported approved SIP carriers increases to 11. In addition, NET also directly supports a wide list of WAN interfaces including T1, PRI, and even broadband MAN solutions. 

A demarcation gateway also increases security for OCS by enabling a direct connection to the carrier. The gateway only accepts and generates calls toward the OCS infrastructure. As an embedded appliance, it cannot be compromised the way a multi-purpose server can.  Internet-based attacks are blocked at the gateway without impact to the remaining OCS servers and services. It also prevents problems with confused firewalls as a result of encryption (firewalls cannot monitor call state when the calls are encrypted).

But the benefits of a demarcation gateway are not just around signaling – the gateway can provide new sets of features to an OCS environment as well. These gateways support traditional trunks as well as SIP trunks and use least cost routing logic to route calls for efficiency, or as a back-up routing alternative, or even for load balancing. For example, with NET’s VX gateways dialing plans can by modified on the fly per carrier (some carriers require a preceding “+”, some carriers reject it).

Interoperability is the key to UC. Sometimes, interoperability as a core architecture within UC makes the solution itself stronger. The trick is utilizing multivendor solutions without increasing risks associated with non-certified/tested solutions. Gateways like NET’s deliver OCS users a supported way of significantly enhancing the telecom capabilities of the solution. By using a specialized demarcation gateway, a variety of benefits are realized for the OCS deployment - including support for additional carriers, additional features, and additional interfaces - without drifting outside of supported configurations.