How to Solve the Interoperability Challenge


Interoperability is the biggest challenge in achieving a successful UC deployment, according to 58% of IT professionals who participated in Nemertes’ research benchmark. Getting various legacy and new systems to share presence information, support click-to-call or click-to-conference, and enable easy management is a difficult-to-overcome challenge.

To mitigate integration and interoperability challenges, Nemertes recommends companies standardize on SIP for system-to-system connectivity. Doing so reduces integration complexity by creating a single communications protocol layer for all UC elements. Enterprise IT architects can simplify deployment and management by managing one suite of protocols rather than separate protocols for each type of UC application. IT managers also can take advantage of emerging SIP-based services for extranet connectivity to support communications and collaboration sessions across company or network boundaries.

Integrating SIP with legacy systems such as TDM or video-conferencing platforms based on the ITU H.323 protocol often requires gateways. An alternative approach melds the two islands into a single unified infrastructure, with a shared service server at the core. Examples include SIP session border controllers capable of transcoding between SIP and non-SIP protocols. For video, one may deploy a server capable of supporting both H.323 and SIP. This server functions as both a H.323 MCU, as well as a SIP proxy server, enabling architects to connect either H.323 or SIP endpoints to a single set of core controllers. In this approach, feature transparency is maintained. The core server (or servers) can provide presence information to other UC applications, while supporting the ability of UC dashboards to initiate conferences regardless of endpoint signaling protocol. This later approach offers a lower total cost of operation, reduced architectural complexity, and elimination of feature disparities.

In addition to interoperability, make sure you address the following requirements for a successful implementation:

Directory: Multiple directories must be consolidated into a single directory infrastructure to avoid overlap.

Lack of usable fax services: Fax over IP has always been the thorn in the side of VOIP. While most VOIP vendors support International Telecommunications Union T.38 enable fax over IP between IP enabled fax machines and PSTN gateways, support for fax has not yet materialized in the SIP trunking market, and interoperability among T.38-based solutions is problematic. Even though fax volumes continue to decline, fax is still a key requirement for contracts. Companies often address fax over IP by deploying fax-to-email solutions for in-bound reception, or by using scanners, or fax machines connected to POTS lines for 0utbound faxing, the later resulting in additional cost and complexity.

E-911: While some SIP trunking providers support E-911 services, passing location information on to local PSAPs (Public Safety Answering Points), IT executives face significant challenges in integrating SIP trunking with their E-911 architectures. Key issues include the inability for SIP trunking providers to pass location information to E-911 call routing services. Most SIP trunking providers are limited in their service areas, meaning that they can’t route E-911 calls to local emergency services offices out of their operating locations. IT architects often rely on local POTS lines for 911 access, as with fax, adding additional cost and complexity.

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