You know Voice over IP (VoIP) can potentially save your company money, especially if your employees make many domestic long distance calls and/or international calls. It can also provide your users with convenience features, such as delivery of voice-mail messages their e-mail boxes. But making the switch can be a little scary. You depend on your telephone service and may not be able to do business without it, so it's important to get it right.
You can smooth the way to make the transition easier by following some or all of the following recommendations.
Note: This information is also available as a PDF download.
#1: Assign responsibility
The first step in planning for a VoIP deployment is to determine who will be responsible for each aspect. In some companies, the telephone system is managed by different personnel than the IT infrastructure. When you move to VoIP, the telephone system becomes part of the IT infrastructure. However, IT personnel may be unfamiliar with the special requirements of telephony applications. It is important to ensure that you have people on staff (either by hiring new employees or training existing ones) who understand the intricacies of VoIP.
#2: Plan a multiple-stage rollout
To avoid the risks involved in switching all your phones over to VoIP at the same time, you can first set up a pilot project for one department or group of users. This allows you to identify any unexpected problems while the impact is on a small scale, and you can find solutions before rolling out to the entire company.
#3: Plan your security strategy
Because VoIP calls are transmitted over the public Internet, the voice packets are subject to some of the same security threats as your data traffic. Unauthorized capture of packets to eavesdrop on conversations, man-in-the-middle and other call tampering, viruses, and IP-based Denial of Service (DoS) attacks that can bring down your VoIP network are all possibilities you need to guard against.
Firewalls, encryption, and virus protection are just as important to protecting your VoIP transmissions as they are to protecting your data. Security should be built into your VoIP deployment from the beginning, not addressed as an afterthought.
This whitepaper outlines a proactive approach to VoIP security.
#4: Consider quality of service
Voice transmissions are less forgiving than other, non-realtime IP transmissions, such as e-mail. Latency, jitter, packet loss, and slow network performance can cause calls to be cut off or voice quality to degrade. Users are used to the high quality of the traditional telephone network (PSTN) and will expect the same from their VoIP service. Newer codecs can provide better tolerance to packet loss, but it's important to ensure that your network has sufficient bandwidth and throughput speeds to handle VoIP properly. Remember that encryption and other security measures can slow network performance.
#5: Evaluate and (if necessary) upgrade the network
Many business networks "just grew that way" and have a conglomeration of components hooked together that may or may not support a realtime application such as VoIP. You should do a complete assessment of the network to ensure that all the cabling, switches, and other network components are of sufficient grade and speed. Infrastructure changes, such as creating separate VLANs for voice and data, need to be taken care of early.
#6: Consider future needs
Plan ahead, both in terms of capacity growth and additional applications you may want to add in the future (such as video conferencing capabilities). If you are upgrading the network now to support an existing number of voice users, it may be more cost effective to go ahead and upgrade the infrastructure to a level that will allow you to address those future needs without tearing it all down and doing it over again.
#7: Have a backup plan (for Internet connectivity)
Unlike PSTN lines, your VoIP service is dependent on your Internet connection. No Internet connectivity means no telephone service. Redundant connections (which can also be aggregated to provide more bandwidth) will prevent loss of your phone service if one ISP should experience downtime.
#8: Have another backup plan (for electrical power)
Residential telephones continue to operate during a power failure because they operate on the electricity provided by the phone line. PBX systems generally require backup power systems, and your VoIP equipment will likewise need uninterruptible power supplies (UPS) and/or backup generators to power the VoIP server, switches, etc., in the event of a power outage.
Another option is Power over Ethernet (PoE) switches, which can be used to power the IP phones. PoE allows access to both power and IP packet transmission over the same cable. You can find more information about PoE here.
#9: Consider cooling needs
Rolling out hundreds or thousands of IP phones powered by PoE could put a heat overload on your wiring closets. Any time you greatly increase the number of electronic components, you have to deal with the generation of more heat, and PoE draws a lot of extra electricity. This may require the installation of extra cooling equipment. It also pays, when selecting equipment, to factor in the energy efficiency ratings of switches and other PoE gear. For more information, see Power and Cooling Considerations for Power-over-Ethernet.
#10: Consider legal, compliance, and safety issues
Remember that if you're in a regulated industry (healthcare, finance, etc.), your VoIP network is subject to the same government compliance requirements as your data network, so it's important to institute measures showing you are protecting the privacy of client data.
Another issue is emergency services (E911). The portability of VoIP equipment complicates the ability for emergency operators to identity the physical location of VoIP callers. The FCC requires that interconnected VoIP providers supply 9-1-1 services to their customers, and providers are required to obtain your physical location so it can be associated with your number(s). If you change locations and take your VoIP equipment with you, make sure you update the physical location information. Of course, if power or the Internet connection is down, your VoIP service won't work, so you should ensure that you have backup emergency phone service (landline or cellular/wireless) on site.
Debra Littlejohn Shinder is a technology consultant, trainer and writer who has authored a number of books on computer operating systems, networking, and security. These include Scene of the Cybercrime: Computer Forensics Handbook, published by Syngress, and Computer Networking Essentials, published by Cisco Press. She is co-author, with her husband, Dr. Thomas Shinder, of Troubleshooting Windows 2000 TCP/IP, the best-selling Configuring ISA Server 2000, and ISA Server and Beyond.
Debra Littlejohn Shinder, MCSE, MVP is a technology consultant, trainer, and writer who has authored a number of books on computer operating systems, networking, and security. Deb is a tech editor, developmental editor, and contributor to over 20 additional books on subjects such as the Windows 2000 and Windows 2003 MCSE exams, CompTIA Security+ exam, and TruSecure's ICSA certification.