Technology and Standards
As opposed to a mediated bottleneck on the Internet, an unmediated bottleneck has not properly deployed Secure Active Queue Management (SAQM) technology. These bottlenecks can effectively be "gamed" or exploited by newer versions of TCP, including "Mustang", "Relentless," and "FAST" which can consume more bandwidth than the other TCP flows sharing the bottleneck. UDP based protocols can also effectively exploit unmediated bottlenecks. Although these newer TCP implementations can be viewed as being "unfair", or impolite to other flows traversing the bottleneck, they are simply exploiting a bug, performance defect or security loophole, due to global synchronization (TCP phase synchronization), in both Passive and Active Queue management systems, such as RED, or WRED. A Secure Active Queue Management (SAQM) system such as the Secure Mediation Controller (SMC), effectively closes this loophole so that all flows receive approximately the same level of service while allowing network operators to set mediation policies that can include throttled and higher bandwidth services for protocols like ISTP.