Softphone is a piece of software that you run on your computer. This software performs the functions of a phone set, with the added benefit of upgrading the interface and feature set as you please.

There are several types of softphones available, some free, some cost money and some are open source. Here is a linkto an article I wrote previously about softphones.

If you’ve tested softphones and found that the quality is sometimes not as good as a hard phone then you’re not alone. The simple reason being, hard phones are usually tested with your phone system and use the same codecsas the phone system while softphones are so easy to configure and by default may not have the matching configuration that works best with your PBX.

Some things to look for to improve voice quality are to make sure you use the proper codecs on your softphone, that you’re PC is connected to a switch that supports QoS and that you’re not running other CPU intensive applications that can disrupt the encoding process on the softphone. If you are implement traffic prioritization, then make sure your computer is plugged into a port that prioritizes for voice.

You can manage only what you can measure. Managing a VoIP network requires some rigorous data collection and special analysis techniques.In addition to measuring latency, jitter and hop counts, it’s essential to calculate an overall voice quality score such as a Mean Opinion Score or R-factor score. 

VoIP monitoring tools calculate such scores by using a formula known as the E-Model. This is calculated based on statistics collected from the network and then taking into consideration factors such as codec compression, jitter, delay, packet loss and hop count. These factors all effect the user’s perception of call quality.

Since you have to take into account many different variables from networking side as well as traditional telecom industry, individually, such tools are not well suited for VoIP management and you need specialized VoIP tools such as the ones available from Agilent Technologies, Brix Networks, Empririx, Radcom and Qovia. These tools not only use MOS technology but also let you systematically gather data and in most cases relate to other network events and statistic to help diagnose problems and create SLA (service level agreement) reports.

VoIP requires robust infrastructure that has to be operational 24×7. If your email goes down for 10 minutes it’s not as critical, but if your voice services go down for 10 minutes, it’s a huge deal!

Keeping in mind how critical voice communications is, it is essential to plan the network accordingly. Don’t go cheap on the essential infrastructure components like network switches, routers and even cabling. Most companies tend to use the cheapest contractor for cabling when it can be one of the most critical components of the network that can haunt you for years to come. Make sure who-ever installs your cabling tests and certifies it for the amount of data that will be pushed through it.

Use intelligent switches that support multiple VLANs and QoS. This will come in handy to segregate different types of traffic, like data and voice traffic and prioritize voice traffic. VLANs allow you to have one physical network but logically have it split into multiple, so your voice can travel on VLAN1 while your data travels on VLAN2. You can have other services like video travel on VLAN3.

This not only provides your users a better experience for different voice, data and video services but also will assist in quicker troubleshooting of network issues as they arise and allow for testing of new services before deployment.

Remember, your entire infrastructure has to perform together. You can’t have one switch supporting VLANs while others don’t and you can’t have switches supporting VLANs while your routers don’t. Make the investment in the beginning and enjoy a successful roll-out instead of having to patch things on a routine basis later on.

If you don’t have in-house expertise for some of these technologies, it makes sense to go to a third party. If your planning is right from the beginning, it will be easier to scale your network and provide the quality of service your users expect.

Remember, you’ll have to provide POE (Power over Ethernet) for your VoIP nodes (handsets). You should have power backup on the POE circuit so your phones will stay operational even if there’s a power failure, users will expect this.

It is tempting to assume that you can simply implement VoIP on your existing network, as most vendors claim, and everything will just work, this is not the case.

For VoIP to be successful you have to have a certain level of service in place. Unlike data packets, voice packets must make it to their destination, if a packet is lost, it cannot be resent without repercussions.

So before you start planning your VoIP roll-out, do some home work, you might have to upgrade your network switches to prioritize voice traffic, you may have to upgrade your routers or even network wiring.

Here is an interesting article from Network World about VoIP analysis tools that will help you along the way.

Remember, not all switches/routers are the same; There is a difference between a high dollar (HP Procurve, Cisco, etc.) switch and a low cost (Linksys, D-Link, Netgear, etc.) switch. I know both might say they support 10/100 MBPS, both might be managed but if you test both side by side in a lab, you will see the difference.

Always have some sort of network traffic sniffer/analyzer in your toolkit, sooner or later, you will need it. Ethereal is a good opensource network packet analyzer to have in your arsenal. Ethereal will let you see the traffic flowing back and forth on your network so you’re not running blind when problems arise with voice quality and end node connectivity.

Know what codec your VoIP devices are using, all codecs are not the same and voice quality along with bandwidth usage is heavily dependent on codec used.