A Comprehensive Strategy: How to Make the Move to IP Telephony

By Cameron Sturdevant  |  Posted 2004-07-12

A Comprehensive Strategy: How to Make the Move to IP Telephony

Proper planning goes a long way toward smoothing the voice-over-Internet Protocol path, but your company should count on sizable equipment, network architecture and cultural changes when making the move to a voice-over-IP telephone system.

Step 1: Upgrade the Network

One of the biggest challenges to implementing an effective voice-over-IP telephony system is remediating the data network to accommodate voice traffic.

Although it is true that packets containing voice and those that contain data look exactly the same to networking equipment, voice packets must be given priority treatment. In other words, voice applications must act like traditional phone systems.

First and foremost, this means that a telephone call made using IP standards should sound like a wireline call, not like one from a cell phone. To achieve this level of quality, routers and switches must be configured to prioritize voice traffic and prevent jitter.

This is a significant undertaking because network applications are built to accommodate packets that arrive after short delays or are out of order. The use of virtual local area networks and switches that support the 802.1p specification is essential. The 802.1p spec allows a switch to prioritize traffic and suppress multicast propagation, thus improving voice quality.

Next page: Preventing outages and powering up Ethernet.

Outages and Ethernet

Step 2: Prevent Outages

IP telephones must work even when the power goes out, just like wireline phones. This will require UPS (uninterruptible power supply) support for every piece of network equipment that handles voice traffic.

Most enterprises currently provide this kind of backup power only to servers and the central PBX. In a voice-over-IP implementation, however, every switch and router between the telephone handset and the iPBX must have reliable backup power.

This will likely mean an extensive investment in wiring-closet UPSes.

Step 3: Power Up with Ethernet

Perhaps the most significant change in the wiring closet is a shift from unpowered to powered switches. In a power over Ethernet (POE) environment, electricity is supplied to the handset from either a powered switch or a mid-span power injector, a device that looks like an Ethernet switch and adds electricity to the network wire pairs to support POE.

eWEEK Labs recommends using powered switches rather than mid-span power injectors to conserve rack space and ease configuration of the new system.

The POE standard also makes it possible for information technology managers to confidently install IP telephone handsets without regard to the manufacturer of the power sourcing equipment. These handsets work in much the same way as traditional telephone receivers, drawing power over the same cable as the data signal. POE significantly eases handset installation by eliminating the need for technicians to hunt down open outlets.

At the most basic level, voice-over-IP equipment requires properly installed Category 5 cabling. Among other things, I.T. staff must ensure that run lengths, connectors and terminators meet specifications. If there is any doubt about the quality of the network cable or its installation, use a testing tool.

Next page: Getting your staff trained and preventing viruses and spam.

Training and Security

Step 4: Get Your Staff Up to Speed

The time and cost of training end users on a new IP system will depend on the number and complexity of the telephony applications that are implemented.

With a normal phone system, it costs about $100 to move a single employee inside the same office. These costs may be significantly reduced with IP because technicians can use familiar network configuration tools.

End-user training costs may increase, however, depending on the number of new applications in the handset (such as directory information) and the level of integration with end-user applications such as unified messaging.

Step 5: Watch Out for Viruses and Spam

I.T. managers also should consider the new security concerns that an IP system brings with it. Although no viruses that specifically target VoIP telephone systems have been reported, it is only a matter of time before such a virus is released. Unwanted calls, or what weve labeled "VoIP spam," also have the potential to become a nuisance.

Next page: Developing an RFQ.


Developing An RFQ for Voice-Over-IP

When writing a request for quotation (RFQ) for a voice-over-IP system, information technology managers should focus on the costs associated with network remediation services. Also, most IP telephony rollouts happen in phases, usually starting with a small number of users at company headquarters and expanding to include users at branch offices. Be sure to identify and quantify the various phases of the IP implementation.

RFQ Outline: IP Telephony System

1. Describe the network infrastructure assessment processes and costs. Focus on network documentation review, network equipment and operating system configuration, logical architecture change implementation and future change management.

2. List the network equipment with which the IP system can interoperate. Include specific vendors whose products have been tested with the VoIP equipment and software.

3. Describe in detail the IP systems IP traffic analysis tools—in particular, those that measure traffic levels and service quality (including busy-hour call attempts, busy-hour call completions and calls per second).

4. Itemize the hardware chassis, cards, modules and other devices you need to support busy-hour call volumes. ("Our company places X number of simultaneous outbound calls during our busy-call hours and receives X number of simultaneous inbound calls during our busy-call hours.")

5. Itemize the software you need to support busy-hour call volumes, including licensing costs and annual maintenance fees for a three-year period. (Assume the same call-volume scenario described above.)

6. Describe the voice-mail system, including license costs per voice mailbox, integration with e-mail system(s) for unified messaging, and additional costs for integration kits or professional services.

7. List and detail any network services that must be implemented to support telephone handsets or any other component of the system, including Dynamic Host Configuration Protocol, Domain Name System and FTP. Include the directory services with which the system can be integrated.

8. List and detail quality- of-service standards supported by the handsets, call processor, media gateways, network switches and other network equipment.

9. Describe security features of the handsets, call managers and other components, including features that will protect the system from any viruses and spam.

10. List and detail available IP handsets, including station features. Highlight equipment that uses the IEEE 802.3af power over Ethernet standard. It might also be a good idea to calculate the total cost of all the IP handsets youll need, both in your companys headquarters and in branch offices.

eWEEK Labs Senior Analyst Cameron Sturdevant can be reached at Cameron_Sturdevant@ziffdavis.com.

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