ModernWorks  has over ten years of experience implementing voice over data technologies, from Voice over Frame Relay to Voice over IP. We offer a Voice over IP (VoIP) consulting and testing service (TESTWorks). It is very important that your data network be prepared to handle VoIP traffic, which has special requirements compared to other data traffic.

VoIP, like video, is a real-time application. It is highly sensitive to network delay and packet loss. In a regular data application, packet loss is dealt with by re-transmitting the lost packets. This is generally not noticed by the end user. If packet loss occurs in a VoIP call, pieces of the conversation literally disappear. If network delay is too high, people on a VoIP call tend to start talking over each other. This creates a very difficult conversation. A one way end-to-end network delay of >150ms is generally considered too high. Another delay issue is the variation in delay, referred to as jitter. Jitter is dealt with by using a memory buffer in the PBX called a jitter buffer. The bottom line is that VoIP requires timely packet delivery and your network must be ready for this if you are seriously considering a VoIP implementation for your business.

To overcome inherent network issues and provide consistent business-quality voice calls, all data hardware in the voice path must support quality of service (QOS) protocols. The voice path is the entire network path between any 2 voice endpoints (telephones, PBX). Some QOS protocols are DiffServ Code Point (DSCP), 802.1p, and 802.1q. A QOS strategy can utilize one or more of these protocols. 

Getting Your Network Ready for VoIP

ModernWorks has created a process to ensure a successful VoIP implementation.

1. Hardware Examination - All data hardware (switches, routers, etc.) in the voice path must support QOS.
2. Cabling Evaluation - All cabling (CAT 5, CAT 6, fibre, etc.) should be certified so that there is no question as to reliability. This can typically be done by your telecommunications provider.
3. Network "Noise" Inspection - We refer to "noise" as any undesirable packet on the network. Bad packets can be caused by failing network adapters or equipment. We also want to minimize broadcast traffic and unused protocols. A type of software called a packet sniffer is used to find network noise. The goal here is to have the network running as efficiently as possible.
4. QOS Strategy Creation - The goal of the QOS strategy is to ensure that VoIP traffic is set to the highest priority possible on the network and that this priority is maintained end to end. The creation of this strategy may require changes to the existing data hardware.
5. Load Simulation Test - A preliminary test is run using voice load simulator software to confirm the effectiveness of the QOS strategy. Depending upon the results, changes may have to be made to the strategy or the data hardware.
6. WAN - If there are multiple sites in a WAN configuration, then all previous steps should be completed for each site. The preliminary load simulation test should be run across all WAN links.
7. Comprehensive Test - A comprehensive load simulation test should be run from 1 to 7 days, 24hrs/day. This test is to verify that the network can maintain the required number of simultaneous voice calls consistently.

Following all the steps in this process is a "Best Practice". Each situation is different and is often driven by budget and time constraints, as well as the complexity of the prospective VoIP implementation. Contact us for more details.