Reducing Internet Latency : A Survey of Techniques and their Merit

Bob Briscoe, Anna Brunstrom, Andreas Petlund, David Hayes, David Ros, Ing-Jyh Tsang, Stein Gjessing, Gorry Fairhurst, Carsten Griwodz, Michael WelzlPeer reviewedPreprin

A Fluid Flow Queuing Network Model for Performance Analysis of Bulk Liquid Terminals

Bulk liquid terminals play a crucial role in enabling the timely discharge and loading of liquid from the tankers and also facilitating oil transport to the hinterland via pipelines and external trucks. However, the speed of operations (and demurrage costs in the likely event of vessel handling delays) depends on the capacities of all terminal resources including berth, loading arms, and storage tank farms. Today, there is a limited understanding of how the interactions among the resources affect the overall vessel sojourn time performance. Using an integrated fluid flow simulation model of a bulk liquid terminal, we are able to gain much insight into the discharge operations of a tanker, in particular, implications of storage tank capacity feedback on the loading arm utilization and vessel sojourn times

Performance modelling of a multiple threshold RED mechanism for bursty and correlated Internet traffic with MMPP arrival process

Access to the large web content hosted all over the world by users of the Internet engage many hosts, routers/switches and faster links. They challenge the internet backbone to operate at its capacity to assure e±cient content access. This may result in congestion and raises concerns over various Quality of Service (QoS) issues like high delays, high packet loss and low throughput of the system for various Internet applications. Thus, there is a need to develop effective congestion control mechanisms in order to meet various Quality of Service (QoS) related performance parameters. In this paper, our emphasis is on the Active Queue Management (AQM) mechanisms, particularly Random Early Detection (RED). We propose a threshold based novel analytical model based on standard RED mechanism. Various numerical examples are presented for Internet traffic scenarios containing both the burstiness and correlation properties of the network traffic

A relationship between different costs of container yard modelling in port using queuing approach

U ovom radu razmatrani su grupni dolasci kontenera na kontenerskom skladištu koji su modelirani višekanalnim sistemom teorije redova čekanja MX/M/c sa c skladišnih dizalica kao kanalima opsluživanja. Pretpostavljeno je da je veličina grupe kontenera, X (broj kontenera y grupi koja dolazi na kontenersko skladište) distribuirana u skladu sa Puasonovskim tipom raspodele. Koristeći opšti izraz za razmatrani model redova čekanja, izveden je izraz za odnos specifičnih troškova koji sadrži verovatnoće stanja sistema, faktor iskorišćenja sistema, srednju vrednost i disperziju veličine grupe. Primenjujući taj izraz, predstavljeni su odgovarajući numerički i grafički rezultati za 1, 2 i 3 skladišne dizalice na kontenerskom skladištu u luci. Takođe ističemo da dobijeni analitički izraz omogućava diskusiju i poređenje vrednosti odnosa specifičnih troškova razmatranih modela redova čekanja MX/M/c sa različitim parametrima performanse luke, kao i poređenja istih sa odnosom specifičnih troškova u odnosu na redove čekanja istraživanih u prethodnim radovima autora koji se odnose na ovaj problem.In this paper we consider batch arrivals of containers at a port container yard which is modeled as a multi-server queue MX/M/c with c yard cranes for the service. It is assumed that the related group size (the number of containers in an arriving group), X is distributed by a Poisson-like distribution. Using a more general formula for such queue models, here it is deduced the expression for the specific cost ratio involving the state probabilities, the utilization factor, the mean and the variance of the group size. Applying this expression, related numerical and graphical results are presented when the number of yard cranes at container yard in port is 1, 2 or 3. We also point out that this expression allows us to discuss and compare the values of specific cost ratio concerning the considered MX/M/c queues with different port performance parameters, as well as with specific cost ratio of the queues investigated in earlier authors' papers on this topic

Datacenter Traffic Control: Understanding Techniques and Trade-offs

Datacenters provide cost-effective and flexible access to scalable compute and storage resources necessary for today's cloud computing needs. A typical datacenter is made up of thousands of servers connected with a large network and usually managed by one operator. To provide quality access to the variety of applications and services hosted on datacenters and maximize performance, it deems necessary to use datacenter networks effectively and efficiently. Datacenter traffic is often a mix of several classes with different priorities and requirements. This includes user-generated interactive traffic, traffic with deadlines, and long-running traffic. To this end, custom transport protocols and traffic management techniques have been developed to improve datacenter network performance. In this tutorial paper, we review the general architecture of datacenter networks, various topologies proposed for them, their traffic properties, general traffic control challenges in datacenters and general traffic control objectives. The purpose of this paper is to bring out the important characteristics of traffic control in datacenters and not to survey all existing solutions (as it is virtually impossible due to massive body of existing research). We hope to provide readers with a wide range of options and factors while considering a variety of traffic control mechanisms. We discuss various characteristics of datacenter traffic control including management schemes, transmission control, traffic shaping, prioritization, load balancing, multipathing, and traffic scheduling. Next, we point to several open challenges as well as new and interesting networking paradigms. At the end of this paper, we briefly review inter-datacenter networks that connect geographically dispersed datacenters which have been receiving increasing attention recently and pose interesting and novel research problems.Comment: Accepted for Publication in IEEE Communications Surveys and Tutorial

A relationship between different costs of container yard modelling in port using queuing approach

U ovom radu razmatrani su grupni dolasci kontenera na kontenerskom skladištu koji su modelirani višekanalnim sistemom teorije redova čekanja MX/M/c sa c skladišnih dizalica kao kanalima opsluživanja. Pretpostavljeno je da je veličina grupe kontenera, X (broj kontenera y grupi koja dolazi na kontenersko skladište) distribuirana u skladu sa Puasonovskim tipom raspodele. Koristeći opšti izraz za razmatrani model redova čekanja, izveden je izraz za odnos specifičnih troškova koji sadrži verovatnoće stanja sistema, faktor iskorišćenja sistema, srednju vrednost i disperziju veličine grupe. Primenjujući taj izraz, predstavljeni su odgovarajući numerički i grafički rezultati za 1, 2 i 3 skladišne dizalice na kontenerskom skladištu u luci. Takođe ističemo da dobijeni analitički izraz omogućava diskusiju i poređenje vrednosti odnosa specifičnih troškova razmatranih modela redova čekanja MX/M/c sa različitim parametrima performanse luke, kao i poređenja istih sa odnosom specifičnih troškova u odnosu na redove čekanja istraživanih u prethodnim radovima autora koji se odnose na ovaj problem.In this paper we consider batch arrivals of containers at a port container yard which is modeled as a multi-server queue MX/M/c with c yard cranes for the service. It is assumed that the related group size (the number of containers in an arriving group), X is distributed by a Poisson-like distribution. Using a more general formula for such queue models, here it is deduced the expression for the specific cost ratio involving the state probabilities, the utilization factor, the mean and the variance of the group size. Applying this expression, related numerical and graphical results are presented when the number of yard cranes at container yard in port is 1, 2 or 3. We also point out that this expression allows us to discuss and compare the values of specific cost ratio concerning the considered MX/M/c queues with different port performance parameters, as well as with specific cost ratio of the queues investigated in earlier authors' papers on this topic

Congestion Control for Streaming Media

The Internet has assumed the role of the underlying communication network for applications such as file transfer, electronic mail, Web browsing and multimedia streaming. Multimedia streaming, in particular, is growing with the growth in power and connectivity of today\u27s computers. These Internet applications have a variety of network service requirements and traffic characteristics, which presents new challenges to the single best-effort service of today\u27s Internet. TCP, the de facto Internet transport protocol, has been successful in satisfying the needs of traditional Internet applications, but fails to satisfy the increasingly popular delay sensitive multimedia applications. Streaming applications often use UDP without a proper congestion avoidance mechanisms, threatening the well-being of the Internet. This dissertation presents an IP router traffic management mechanism, referred to as Crimson, that can be seamlessly deployed in the current Internet to protect well-behaving traffic from misbehaving traffic and support Quality of Service (QoS) requirements of delay sensitive multimedia applications as well as traditional Internet applications. In addition, as a means to enhance Internet support for multimedia streaming, this dissertation report presents design and evaluation of a TCP-Friendly and streaming-friendly transport protocol called the Multimedia Transport Protocol (MTP). Through a simulation study this report shows the Crimson network efficiently handles network congestion and minimizes queuing delay while providing affordable fairness protection from misbehaving flows over a wide range of traffic conditions. In addition, our results show that MTP offers streaming performance comparable to that provided by UDP, while doing so under a TCP-Friendly rate