The last several years has seen a renewed interest in smart queue management to curb excessive network queueing delay, as people have realised the prevalence of bufferbloat in real networks. However, for an effective deployment at today's last mile connections, an improved queueing algorithm is not enough in itself, as often the bottleneck queue is situated in legacy systems that cannot be upgraded. In addition, features such as per-user fairness and the ability to de-prioritise background traffic are often desirable in a home gateway.In this paper we present Common Applications Kept Enhanced (CAKE), a comprehensive network queue management system designed specifically for home Internet gateways. CAKE packs several compelling features into an integrated solution, thus easing deployment. These features include: bandwidth shaping with overhead compensation for various link layers; reasonable DiffServ handling; improved flow hashing with both per-flow and per-host queueing fairness; and filtering of TCP ACKs. Our evaluation shows that these features offer compelling advantages, and that CAKE has the potential to significantly improve performance of last-mile internet connections.
Having control of the bottleneck queue makes it possible to implement effective queue management that can all but eliminate bufferbloat. Such a queue management scheme usually takes the form of an Active Queue Management (AQM) algorithm, combined with a form of fairness queueing (FQ). Several such schemes exist, and extensive evaluation is available in the literature (e.g., @cite_6 @cite_7 @cite_5 @cite_19 @cite_12 @cite_20 ).
@cite_7 @cite_6 @cite_19 @cite_5 @cite_20 @cite_12
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In the past, networks have been mainly optimized for good system throughput but recently achieving low delay has also gained notable traction. Active Queue Management (AQM) has long been recognized necessary for operating Internet routers with shorter standing queues but only limited deployment has occurred. The recent interest in AQM has resulted in new AQM proposals. In this paper we evaluate CoDel (Controlled Delay) and PIE (Proportional Integral controller Enhanced), both being new AQM proposals, and compare the performance against an aggressive RED (Random Early Detection) variant called HRED (Harsh RED). We focus on AQM behavior during load transients typically occurring at the network edge with the common traffic types of today such as Web transactions. We discover that CoDel auto-tuning does not scale well with the load. With the high-end delays experienced, HRED is better than PIE and CoDel when more than a few simultaneous flows share the bottleneck. Several new active queue management (AQM) and hybrid AQM fairness queueing algorithms have been proposed recently. They seek to ensure low queueing delay and high network goodput without requiring parameter tuning of the algorithms themselves. However, extensive experimental evaluations of these algorithms are still lacking. This paper evaluates a selection of bottleneck queue management schemes in a test-bed representative of residential Internet connections of both symmetrical and asymmetrical bandwidths as well as WiFi. Latency under load and the performance of VoIP and web traffic patterns are evaluated under steady state conditions. Furthermore, the impact of the algorithms on fairness between TCP flows with different RTTs, and also the transient behaviour of the algorithms at flow startup is examined. The results show that while the AQM algorithms can significantly improve steady state performance, they exacerbate TCP flow unfairness. In addition, the evaluated AQMs severely struggle to quickly control queueing latency at flow startup, which can lead to large latency spikes that hurt the perceived performance. The fairness queueing algorithms almost completely alleviate the algorithm performance problems, providing the best balance of low latency and high throughput in the tested scenarios. However, on WiFi the performance of all the tested algorithms is hampered by large amounts of queueing in lower layers of the network stack inducing significant latency outside of the algorithms' control. The availability of cheaper and high capacity Random Access Memory (RAM) has resulted in the growth of buffer size in all the computing devices. This aberrant increase of buffer capacity in network devices has resulted into high latency, leading to reduced throughput; thus decreasing the tendency of absorbing spontaneous burst of traffic. The requirement for Active Queue Management (AQM) has been evident for decades. These solutions require various parameter configuration and are dependent on a particular network condition to work efficiently. Hence an algorithm which is simple, efficient, does not require setting of parameters and works seamlessly irrespective of the network condition is required. Even though Controlled Delay (CoDel) is parameterless and adapts to dynamically changing link rates with no negative impact on utilization, it deviates from its primary purpose of reducing congestion when there is an increase in RTT and when congestion level varies abruptly. As a consequence, a variant of CoDel called Stochastic Fair Queue CoDel (sfqCoDel) is simulated and compared. The Stochastic Fair Queue CoDel proactively drops packets which occupy reasonably larger bandwidth as compared to CoDel, which proactively drops packet irrespective of the bandwidth consumption by packets. This paper aims to perform a comprehensive analysis of Stochastic Fair Queue CoDel for Active Queue Management. A comparison is also carried out between sfqCoDel with CoDel. The sfqCoDel appears to be much better than CoDel in certain areas where CoDel fails to perform well. Active Queue Management (AQM) design has again come into the spotlight of network operators, vendors and OS developers. This reflects the growing concern and sensitivity about the end-to-end latency perceived by today’s Internet users. Indeed, delays on the order of seconds have become common due to the deployment of excessively-sized FIFO DropTail buffers at the edge of many networks. CoDel and PIE are two AQM mechanisms that have recently been presented and discussed at the IRTF and the IETF. However, to the best of our knowledge, they have not yet been thoroughly evaluated or compared against each other except by simulation. We set thus to perform an experimental evaluation using real-world implementations, in both wired and wireless testbeds. We have in addition compared them with a decade-old variant of RED called Adaptive RED, which shares with CoDel and PIE the goal of “knob-free” operation. Surprisingly, in many instances results were much more favorable towards Adaptive RED. We do not call into question the need for new AQMs, however, there are lessons yet to be learned from old designs. Since its formal introduction to IP networks in 1993 as a viable complementary approach for congestion control, there has been a steady stream of research output with respect to Active Queue Management (AQM). This survey attempts to travel the trajectory of AQM research from 1993 with the first algorithm, Random Early Detection (RED), to current work in 2011. In this survey we discuss the general attributes of AQM schemes, and the design approaches taken such as heuristic, control-theoretic and deterministic optimization. Of interest is the role of AQM in QoS provisioning particularly in the DiffServ context, as well as the role of AQM in the wireless domain. For each section, example algorithms from the research literature are presented.