A major shift in telecommunications from circuit to packet switched technology, along with increasing sophistication of the corporate LAN/WAN, is prompting businesses of all sizes to consider merging their voice and data networks. Increased bandwidth availability through gigabit Ethernet and fiber trunk lines allow for telephony to be treated as any other application on the IP network, albeit a very needy one.



Whereas the main motivation for individual consumers to make the switch to VoIP may be cost, as evidenced by the acceptance of such upstarts as Vonage, for businesses, the transition to IP telephony (IPT) could mean a costly network upgrade, fueled by aging or depreciated legacy PBX equipment.

The upside is the imediate potential of adding strategic business capabilities - a triple play of voice, video, and data - and future proofing the network for a host of real and non realtime applications under the concept called Unified Communications. Data and communications, all managed and maintained over one network instead of two.

The Life Cycle of an IPT Network

Just like any major network undertaking, best practices dictate that deployment take place in stages, the success of each successive phase depending on the previous. The first stage is planning and assessment, followed by an intense pre deployment testing and implementation stage, and once the migration has taken place, the ongoing operations and optimizations stage. Taken together, these phases of deployment are what is known as the converged IPT network life cycle.

Planning and Assessment: Business Drivers

The business case for convergence must be clear from the beginning. Why trash a perfectly functioning telephone network with a reliable reputation for a new, burgeoning technology, as of yet only minimally tested? If indeed your existing phone system is out of date, replacement parts are getting hard to find, or its functionality no longer suits the needs of a growing organization, one motivation for converging could be the unwillingness to invest in a new Centrex-centric PBX, based on circuit switched technology.

Managing Expectations

A successful deployment from start to finish should take about a year, with a good 6 months devoted to planning and testing. For organizations that have recently upgraded their network infrastructure, deploying a converged network may not be as costly as networks that are older, and require major renovation.

Realistically, it has been observed that migrating from a legacy PBX to an IP PBX will cost as least as much as buying a new TDM PBX. Where you may get your ROI is on moves, adds, and changes (MAC) in the new IP environment. Studies show that MAC on a TDM system averages about $65, vs. $10 on an IP PBX.

Equally important is managing the expectations of your end users. Let them know early on about deployment plans and keep them apprised of your progress. End users should be surveyed on what aspects of the current system they consider critical to their job functions, and what improvements they would like to see in the new system. Call and voice quality are understandably critical factors to users and like the carrier network you are about to replace, Service Level Agreements (SLA) play an important role to insure acceptable customer service.

Planning for Security

Security considerations are of utmost importance in the planning phase. Treat your PBXs as any other critical application server by keeping it protected from public access, perhaps even in it's own DMZ. Remember that an IP PBX has all the vulnerabilities of IP, and it opens up a whole new Pandora's Box with a connection to the PSTN. Firewalls and intrusion detection should be utilized appropriately and should be current enough to recognize voice traffic.

Also consider segregating your voice traffic through the use of virtual LANs. A VLAN can help increase network performance while having the added benefit of enhanced security.

Hosted vs. In-house

Early consideration should be given to the options available for the type of voice network to deploy, as well as who will be responsible for the deployment. For businesses simply wanting to implement a VoIP solution, a hosted IP PBX can leap frog you into the future, while saving on equipment costs and reducing the headaches associated with a long drawn out deployment process.

For organizations looking to future proof their network, vendor equipment must be chosen and assessed, as well as the management applications being considered for the deployment. Costs associated with upgrading the skill sets of the IT and/or Telephony staff must also be taken into consideration.

Calling in the Pros

Organizations that plan to migrate to IP telephony themselves but find they lack the necessary expertise, might consider bringing in a Systems Integrator to help with the deployment. A Systems Integrator should be chosen and brought in early in the project. They should work closely with the IT department and can also take on the role of trainer in getting them up to speed on the new technology. The cost of bringing in an outsider can be upwards of 20% of the entire project, but may be worth it to assure a seamless transition.

The Managed Service Provider

A growing trend in the industry is for businesses to offload all or part of VoIP deployment responsibilities to a Managed Service Provider. Carriers, equipment vendors, and professional services that now have a couple of years of experience in the field are finding that companies are willing to pay for their expertise. For businesses that find that their IT staff is not up to the task, or could be utilized better elsewhere, an MSP provides the option of outsourcing projects anywhere from doing the network assessment and capacity planning, to taking on the whole ongoing management phase, much like business was doing with their legacy telephony service providers.

Management Solutions

For the enterprise that is planning to leave it up to the IT and Communications departments, now is the time to consider third party management and analysis applications. Third party solutions are just now coming into the market that take a more holistic approach to management, looking at the effects of both real time and not so real time applications on the network as a whole. Solutions being considered should be assessed for their usefulness in the testing stage of deployment. More on these management applications in the ongoing operations and optimization part of this paper.