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Native 10Gigabit Ethernet experiments over long distances

The current solutions for transmitting data over Wide Area Networks (WANs) are expensive and require protocol translation at layer 1. The IEEE recently standardized the 10Gigabit Ethernet (10GE) WAN PHY as a native gateway from the Local Area Networks (LAN) to the WAN. This opened a debate as to whether Ethernet is now a valid alternative to Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) for WANs. In this article, we report on the experience gathered while building the first trans-European native 10Gigabit Ethernet testbed based on WAN PHY. We describe and analyze network tests with a 1700km Ethernet network. Our work validates this approach and indicates that Ethernet can offer a large bandwidth to long-distance bulk data transfers at a trans-European level.

Microscopic examination of TCP flows over transatlantic links

Much of the recent research and development in the area of high-speed TCP is focused on the steady state behavior of TCP flows. However, our experience with the first research only transatlantic 2.5 Gbps Lambda link clearly demonstrates the need to focus on the initial stages of TCP. The work we present here examines the behavior of TCP flows at microscopic level over high-bandwidth long delay networks. This examination has led us to study the influence of the minute properties of the underlying network on bursty protocols such as TCP at these very high speeds combined with high latency. In this paper we briefly describe the requirements for such an extreme network environment to support high-speed TCP flows. We also present results collected using transatlantic links at iGrid2002 where we tuned various host parameters and used modified TCP stacks.

Visualizing Evolutionary Dynamics of Self-Replicators: A Graph-Based Approach

We present a general approach for evaluating and visualizing evolutionary dynamics of self-replicators using a graph-based representation for genealogy. Through a transformation from the space of species and mutations to the space of nodes and links, evolutionary dynamics are understood as a flow in graph space. A formalism is introduced to quantify such genealogical flows in terms of the complete history of localized evolutionary events recorded at the finest level of detail. Represented in a multidimensional viewing space, collective dynamical properties of an evolving genealogy are characterized in the form of aggregate flows. We demonstrate the effectiveness of this approach by using it to compare the evolutionary exploration behavior of self-replicating loops under two different environmental settings.

Visualizing Evolutionary Dynamics of Self-Replicators Using Graph-Based Genealogy

We present a general method for evaluating and visualizing evolutionary dynamics of self-replicators using a graph-based representation for genealogy. Through a transformation from the space of species and mutations to the space of nodes and links, evolutionary dynamics are understood as a flow in graph space. Mapping functions are introduced to translate graph nodes to points in an n-dimensional visualization space for interpretation and analysis. Using this scheme, we evaluate the effect of a dynamic environment on a population of self-reproducing loops. Resulting images visually reveal the critical role played by genealogical graph space partitioning in the evolutionary process.

Exploring practical limitations of TCP over transatlantic networks

Tomorrows large physics and astronomy projects will require to transport tremendous amounts of data over long distances in near real time. Traditional TCP implementations have severe problems in reaching the necessary performance. In the recent past, researchers have shown that TCP implementations can be scaled to achieve multi-gigabit per second speeds over high-bandwidth high-delay networks. The ability of TCP to scale to high speeds opens possibilities for very large data transfers over vast distances. We analyze here whether TCP can fulfill this task and what problems we are faced with. We also examine TCP in the context of dedicated links (Lambdas).

iGrid2002 demonstration: bandwidth from the low lands

We report on a demonstration of several complementary high-performance end-to-end active network throughput measurement tools. These include: the PingWorld Java applet that displays the Round Trip Time (RTT) and losses to sites around the world from the users host; the multi-path analysis tool that visualizes common paths from traceroutes to selected hosts; the IEPM high-performance BandWidth monitoring toolkit which gives achievable throughput for several types of TCP data transfer applications; and the Available Bandwidth Estimation (ABWE) tool that reports in real-time the available bandwidth to several paths within the range from Mbits/s to Gbits/s. We also demonstrated sending high-speed data from 4 hosts at iGrid2002 to over 30 hosts in 10 countries to simulate a high energy physics experiment distributing data to collaborators. The demonstration utilized the high-speed, long latency, trans-Atlantic network set up for iGrid2002 in Amsterdam during September 2002.

TCP Behavior on Transatlantic Lambda’s

Recent research in the area of high speed TCP has revealed that the protocol can misbehave in cases of high bandwidth long delay networks. Here we present work that clearly demonstrates this behavior of TCP flows in detail. This examination has led us to study the influence of the underlying network as well as the end user system using bursty a protocol such as TCP under such conditions. We describe briefly what the requirements are for such an extreme network environment to support high speed TCP flows.