Intelligent Flow Discard
Congestion is inevitable within any IP network. Since most networks suffer performance problems during congestion that result in extreme delays, lost connections, and disappointed users, many networks are "designed" with enormous amounts of excess capacity in terms of both transmission facilities as well as router ports. This excess build-out is essentially a crude attempt to allay the threat of congestion by building more than enough "buffer space" to handle the inevitable activity peaks and usage spikes that can render even the most aggressively designed networks inadequate. This "pay and pray" approach of purchasing more and more transmission and networking equipment is doomed to failure over the long run, since the overall volume of network traffic is now accelerating at a rate that far outpaces Moore's Law – network traffic is doubling every 12 months while overall packet processing power doubles roughly every 18 months. The numbers simply do not line up - a better solution is required and fortunately Anagran has that solution in the form of Intelligent Flow Discard™ (IFD).
IFD is an innovative form of congestion control that takes a proactive metering approach to managing flows as they arrive. Since the FR-1000 maintains vital state information on every flow while constantly measuring output load on each port, it can intelligently meter incoming traffic by flow class as it arrives, by dropping single packets from just the right flows at just the right time to optimize the performance of TCP traffic as congestion escalates. Since traditional network equipment has no insight into flow state, packets normally get dropped across many and eventually all flows as congestion escalates. In essence, all traffic suffers including time-critical traffic like video and voice. By metering based on flow class, the Anagran FR-1000 can fully protect these vital video and voice services while penalizing only those flows that are instigating the congestion in the first place. As a result, IFD serves to not only complement existing routers, but it also protects them, and the downstream network, as well.
For TCP traffic, IFD ensures equitable use of network capacity for all traffic based on flow class. For UDP traffic like streaming video and VoIP, IFD ensures constant flawless quality by automatically invoking Call Admission Control (CAC) whenever an incoming stream threatens the quality of existing streams. Pre-emption of existing flows by higher priority flows is also possible for emergency services applications, for example. It is important to note that the FR-1000 ability to automatically invoke Call Admission Control on UDP streams is an inherent capability of the product, and requires absolutely no external signaling mechanisms which are known to face serious latency and scalability challenges.
