Kentrox, provider of the Q1300 QoS Appliance, recently published a new whitepaper that explains what VoIP Quality of Service (QoS) is, why it’s important, and how products from the company provide the necessary tools to keep your network healthy.

 

This article is a summary of the whitepaper, which can be downloaded here.

 

For those not familiar with the term “Quality of Service” or “QoS,” Kentrox offers the following definition: “the ability of a network to provide individualized service to selected network traffic over various underlying technologies including Frame Relay, ATM, Ethernet and 802.1 networks, SONET, and IP-routed networks.”

 

Wow, that’s a mouthful. You might be asking, “Why do I need QoS?”

 

Kentrox answers that, too: “Newer applications such as Voice over Internet Protocol (VoIP) and real-time video conferencing cannot tolerate glitches in network performance. A delay of even 1/6th of a second can impact voice call quality.”

 

So there you have it. According to Kentrox, the Wide Area Network (WAN) is the most important area where QoS is needed, because where WAN meets LAN, traffic bottlenecks can occur that reduce speeds from Gigabit to fractional T1.

 

“This is where routing buffers overflow and data gets delayed and discarded,” Kentrox explains. “Real-time applications cannot tolerate these factors, and the quality of the user experience suffers.”

 

QoS resolves potential traffic problems by pulling high-priority VoIP packets into a separate queue, allowed them through first.

 

“The best effort data can then be buffered and/or discarded as needed. This non-real-time application can recover via retransmission and the network is optimal,” Kentrox said.

 

There are quite a few different ways in which QoS can be implemented, according to Kentrox. In the whitepaper, the company provides some pretty technical information about those different types, which are divided into two main categories, listed below.

 

Layer 2 Implementations

            ATM Adapation Layers

            Frame Relay CIR

 

Layer 3 Implementations

            Integrated Services (IntServ)

            Type of Service (TOS)

            Differentiated Services (DiffServ)

 

The whitepaper focuses mostly on Layer 3 QoS, in particular DSCP, because that’s the most dominate type, Kentrox said.

 

Broadly, the benefit of DSCP is that it “allows each packet to be marked with the traffic requirements of the enclosed data.” For a more technical explanation, see the whitepaper.

 

Kentrox’s line of Quality of Service solutions, designed specifically for small to medium sized business, come preconfigured to support all DiffServ classes.

 

“The products can also remark DSCP bits to prepare each packet for its journey across the network,” Kentrox said in the whitepaper.

 

The company is all about usability. It’s QoS products provide a user-friendly Graphical User Interface for easy of configuration, which is performed via point-and-click dropdown menus.

 

To learn more, visit Kentrox’s VoIP Quality of Service channel on TMCnet.com, and the company website at http://www.kentrox.com.

 

 

VoIP Quality of Service