This month we continue our series on evaluating VoIP voice quality. Voice quality, of course, is the bottom line in determining whether your VoIP network is accepted by end users. Implementors must be prepared with standards-based measurement tools to track and fine-tune voice quality. Based on the vendor responses received from the first column in this series (April 2002), there are now, more than ever, excellent tools available to help you with this critical task.

TOOLS FOR EVALUATING NETWORK QOS

For the moment, let's assume that whatever VoIP gateways or IP phone devices you are using are operating properly. That is, they do not suffer from internal defects that would themselves degrade voice quality. Thus, any voice-quality problems that callers experience would be the result of network transport issues. One of the things you'll need in your VoIP network-builder toolkit is the ability to monitor the quality of the data circuit upon which VoIP calls will ride. Here are two companies that produce solid network QoS monitoring tools:

NetIQ (San Jose, CA - 408-856-3000, www.netiq.com) produces an innovative product called the Chariot VoIP Assessor, which generates simulated VoIP traffic and produces in-depth reports that predict how well VoIP will work on your network. Among the reporting tools is an executive summary "go/no go" report, plus reports to help you pinpoint where network improvements need to be made. We cannot emphasize enough how important it is to test your network before you add VoIP endpoints. The Chariot uses something called the "E-model" to convert measured data circuit impairments (i.e. packet loss, jitter, and latency) into an "R Factor" from 0 to 100, which is mapped to an equivalent MOS estimate of effective voice quality over time. The R Factor calculation takes into account what types of codecs you plan to use in your endpoints. Highly recommended.

NetIQ's other VoIP measurement products provide additional diagnostic drill-down capabilities: VoIP Manager Suite is a powerful real-time monitoring tool, and Chariot, their workhorse network performance test tool, supports a VoIP Test Module.

Kahala Systems (Orange, CA - 714-516-9229, www.kahalasystems.com) is a smaller company with several interesting offerings that can be downloaded as trial versions off their website. activStream generates simulated real-time media streams using RTP on a network in a controllable, measurable way. More than a traffic generator, it simulates audio with voice-modeling that mirrors human speech patterns. activStream Standard provides tools to turn up VoIP services. It sends real-time media streams to nodes on the network or even network analyzers like Kahala System's wav.3 or Acterna's DNA-323, to measure performance. activStream Professional connects to any number of Testpoints hosted on Windows servers or PCs located at strategic points in your network. Real-time media streams are sent to and from the Testpoints and analyze how the network responds. With no "per-seat" license fees, you can deploy as many Testpoints as needed.

MORE FEEDBACK

In closing, I recently received a bit of interesting feedback from a vendor of a VoIP QoS monitoring tool:

Dear Dr. C:

Your case for an ITSP/CLEC installing standards-based VoIP gear along with a "real-time monitoring solution" is very valid. Our company Amoebatel (www.amoebatel.com) makes a real-time VoIP voice quality monitoring solution that provides reports on poor voice quality for every call. We would like to share some recent feedback from customers:

1. Unfortunately, we find many of the service providers to whom we have shown our solution consider real-time VoIP QoS monitoring "nice to have" and not a "must have."

2. Many have cited that they have not yet reached the capacity to justify installation of a real-time QoS monitoring solution.

3. Many SPs are also stuck with gateways supporting non-standard protocols, whose manufacturers are not willing to share the proprietary protocol information to a monitoring company like us.

4. Lastly, the current market conditions are forcing CLECs to conserve dollars; they therefore are reluctant to budget for the "nice to have" products.

Regards, Siva

Sometimes, reality bites. More next month.

Chris Bajorek is co-founder of CT Labs, an independent full-service converged communications and IP Telephony product testing and certification lab. He can be reached at cbajorek@ctlabs.com.

This month we continue our series on evaluating VoIP voice quality. Voice quality, of course, is the bottom line in determining whether your VoIP network is accepted by end users. Implementors must be prepared with standards-based measurement tools to track and fine-tune voice quality. Based on the vendor responses received from the first column in this series (April 2002), there are now, more than ever, excellent tools available to help you with this critical task.

TOOLS FOR EVALUATING NETWORK QOS

For the moment, let's assume that whatever VoIP gateways or IP phone devices you are using are operating properly. That is, they do not suffer from internal defects that would themselves degrade voice quality. Thus, any voice-quality problems that callers experience would be the result of network transport issues. One of the things you'll need in your VoIP network-builder toolkit is the ability to monitor the quality of the data circuit upon which VoIP calls will ride. Here are two companies that produce solid network QoS monitoring tools:

NetIQ (San Jose, CA - 408-856-3000, www.netiq.com) produces an innovative product called the Chariot VoIP Assessor, which generates simulated VoIP traffic and produces in-depth reports that predict how well VoIP will work on your network. Among the reporting tools is an executive summary "go/no go" report, plus reports to help you pinpoint where network improvements need to be made. We cannot emphasize enough how important it is to test your network before you add VoIP endpoints. The Chariot uses something called the "E-model" to convert measured data circuit impairments (i.e. packet loss, jitter, and latency) into an "R Factor" from 0 to 100, which is mapped to an equivalent MOS estimate of effective voice quality over time. The R Factor calculation takes into account what types of codecs you plan to use in your endpoints. Highly recommended.

NetIQ's other VoIP measurement products provide additional diagnostic drill-down capabilities: VoIP Manager Suite is a powerful real-time monitoring tool, and Chariot, their workhorse network performance test tool, supports a VoIP Test Module.

Kahala Systems (Orange, CA - 714-516-9229, www.kahalasystems.com) is a smaller company with several interesting offerings that can be downloaded as trial versions off their website. activStream generates simulated real-time media streams using RTP on a network in a controllable, measurable way. More than a traffic generator, it simulates audio with voice-modeling that mirrors human speech patterns. activStream Standard provides tools to turn up VoIP services. It sends real-time media streams to nodes on the network or even network analyzers like Kahala System's wav.3 or Acterna's DNA-323, to measure performance. activStream Professional connects to any number of Testpoints hosted on Windows servers or PCs located at strategic points in your network. Real-time media streams are sent to and from the Testpoints and analyze how the network responds. With no "per-seat" license fees, you can deploy as many Testpoints as needed.

MORE FEEDBACK

In closing, I recently received a bit of interesting feedback from a vendor of a VoIP QoS monitoring tool:

Dear Dr. C:

Your case for an ITSP/CLEC installing standards-based VoIP gear along with a "real-time monitoring solution" is very valid. Our company Amoebatel (www.amoebatel.com) makes a real-time VoIP voice quality monitoring solution that provides reports on poor voice quality for every call. We would like to share some recent feedback from customers:

1. Unfortunately, we find many of the service providers to whom we have shown our solution consider real-time VoIP QoS monitoring "nice to have" and not a "must have."

2. Many have cited that they have not yet reached the capacity to justify installation of a real-time QoS monitoring solution.

3. Many SPs are also stuck with gateways supporting non-standard protocols, whose manufacturers are not willing to share the proprietary protocol information to a monitoring company like us.

4. Lastly, the current market conditions are forcing CLECs to conserve dollars; they therefore are reluctant to budget for the "nice to have" products.

Regards, Siva

Sometimes, reality bites. More next month.

Chris Bajorek is co-founder of CT Labs, an independent full-service converged communications and IP Telephony product testing and certification lab. He can be reached at cbajorek@ctlabs.com.