Quality of Service Testing Most inter-networking technologies have deployed various levels and schemes for Quality of Service (QoS). IT managers can now allocate bandwidth (or at least give a higher priority) for specific users or applications. This greatly reduces contention for high-capacity applications like video-streaming, Voice over IP; backup and other applications that need to act like in a more "connection" oriented environment. When initially deployed it is difficult for IT professionals to fine-tune the QoS policies within their equipment. Basically you have to have a fully running network with actual traffic, each contending for bandwidth. Of course you could set up a multitude of client machines to generate the amount of traffic required and have some sort of software agent facilitating this, but this is impractical. FlameThrower / BitStressor provides a compact and efficient means of testing QoS setup and allows the IT professional to adjust policies on the fly and immediately seeing the results. In fact, FlameThrower / BitStressor was used in recent public demonstrations to prove the QoS capabilities of high-end switches from both Extreme Networks and Foundry Networks. To do this type of testing FlameThrower only requires a connection to the network infrastructure at strategic points (i.e. on multiple sides of a backbone) and connection to ports or vlans configured with the QoS the user wants to test. Traffic setup is a simple point and click proposition with the ability to produce all forms of legal and illegal streams of data. The enc (Sniffer™ trace file format) file playback feature could also be used to test QoS based on an application profile to see if that type of traffic gets high priority or not. You can also throttle the traffic on a port by port basis to see how QoS reacts to real-world "peaks and valleys" conditions. If you have gigabit Ethernet between devices you need a method of stressing the gigabit link up to and beyond capacity (at full duplex this is 2Gbps). Because of most devices’ internal buffering and caching algorithms, this takes a minimum of 12, 100 Mbps ports on each side of the link to fully saturate the wire. FlameThrower can easily accommodate this. To see if QoS is working, most equipment these days has internal statistics showing what traffic is getting through and what is being dropped. Even FlameThrower could be used as a capture point to see statistics on what is coming and going from specific segments.