Abstract not found

Tools to measure internet properties usually assume the existence of just one single path from a source to a destination. However, load-balancing capabilities, which create multiple active paths between two end-hosts, are available in most contemporary routers. This paper proposes a methodology to identify load-balancing routers and characterize loadbalanced paths. We enhance our traceroute-like tool, called Paris traceroute, to find all paths between a pair of hosts, and use it from 15 sources to over 68 thousand destinations. Our results show that the traditional concept of a single network path between hosts no longer holds. For instance, 39 % of the source-destination pairs in our traces traverse a load balancer. Furthermore, this fraction increases to 70% if we consider the paths between a source and a destination network.

Traceroute is widely used: from the diagnosis of network problems to the assemblage of internet maps. Unfortunately, there are a number of problems with traceroute methodology, which lead to the inference of erroneous routes. This paper studies particular structures arising in nearly all traceroute measurements. We characterize them as “loops”, “cycles”, and “diamonds”. We identify load balancing as a possible cause for the appearance of false loops, cycles and diamonds, i.e., artifacts that do not represent the internet topology. We provide a new publicly-available traceroute, called Paris traceroute, which, by controlling the packet header contents, provides a truer picture of the actual routes that packets follow. We performed measurements, from the perspective of a single source tracing towards multiple destinations, and Paris traceroute allowed us to show that many of the particular structures we observe are indeed traceroute measurement artifacts. 1

Abstract—Traceroute is a tool to report the route packets take between two internet hosts. However, with the deployment of load balancing, there is no longer a single route to a destination, hence classic traceroute systematically misses some of these paths. In this paper, we specify an adaptive, stochastic probing algorithm, called the Multipath detection algorithm, to report all paths towards a destination. We have deployed this algorithm, probing from a single source towards multiple destinations. In our results, we have found instances of load balancing with as many as 16 interfaces per hop. The algorithm also allows us to count load balancing routers, identify their locations, and characterize them by type.

Efficient and cost-effective measurement of network characteristics is pivotal for distributed systems deployed on the Internet. The network characteristics are utilized by Internet-based distributed systems to provide better service to the user and enhance performance for the application. This chapter provides a detailed analysis of existing techniques for the measurement of the four important network characteristics which include latency, bandwidth, path detection and loss rate. The chapter describes key concepts related to network measurements, including techniques for clock synchronization, strategies for time stamping of probes, methods for network analysis, difference between active and passive measurements and comparison of round trip vs. one way delay measurements. It elaborates the usefulness of different transport and network layer protocols (i.e. TCP, UDP and ICMP) for obtaining network measurements and continue this discussion to describe some important measurement tools such as Ping, Traceroue, Pathchar, Sting, Scriptroute, Spruce and Paris Traceroute. The chapter explains the effectiveness and limitations of these tools with respect to the measurement of network characteristics. 1.

Abstract not found