Conference Paper

End-to-End Asymmetric Link Capacity Estimation.

DOI: 10.1007/11422778_63 Conference: NETWORKING 2005: Networking Technologies, Services, and Protocols; Performance of Computer and Communication Networks; Mobile and Wireless Communication Systems, 4th International IFIP-TC6 Networking Conference, Waterloo, Canada, May 2-6, 2005, Proceedings
Source: DBLP

ABSTRACT Knowledge of link capacity is important for network design, management, and utilization. With the increasing popularity of asym- metric link technologies (such as DSL, 1xRTT, and satellite links), it is desirable to have a capacity estimation technique, which can simulta- neously measure forward and backward direction link capacities on an Internet path. Moreover, this estimation must often be "sender only", because of receiver limitations or lack of standards. In this study, we propose a simple, fast and accurate technique, called AsymProbe, to es- timate asymmetric link capacities. AsymProbe is a "sender only", round trip procedure. It achieves asymmetric link capacity estimation by strate- gically altering the ratio of probe and acknowledgement packet sizes. Us- ing simulation and testbed experiments, we validate AsymProbe with a variety of network configurations. The results show that AsymProbe can correctly estimate the asymmetric link capacities as long as an appropri- ate packet size ratio can be employed.

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    ABSTRACT: Measuring network path capacity is an important capability to many Internet applications. But despite over ten years of effort, the capacity measurement problem is far from being completely solved. This paper addresses the problem of measuring network paths of asymmetric capacity without requiring the remote node's control or overwhelming the bottleneck link. We first show through analysis and measurement that the current packet-dispersion methods, due to the packet size limitations, can only measure up to a certain degree of capacity asymmetry. Second, we propose TRIO that removes the limitation by using round-trip times (RTTs). TRIO cleverly exploits two types of probes to obtain three minimum RTTs to compute bothforward and reverse capacities, and another minimum RTT for measurement validation. We validate TRIO's accuracy and versatility on a testbed and the Internet, and develop a system to measure path capacity from the server or user side.
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    ABSTRACT: Knowledge about the bottleneck capacity of an Internet path is critical for efficient network design, management, and usage. In this paper, we propose a new technique, called PBProbe, for estimating high speed links rapidly and accurately. Although it is based on CapProbe, instead of relying solely on packet pairs, PBProbe employs the concept of “Packet Bulk” and adapts the bulk length to compensate for the well known problem with packet pair-based approaches, namely the lack of accurate timer granularity. As a result, PBProbe not only preserves the simplicity and speed of CapProbe, but also correctly estimates link capacities over a much larger range. Using analysis, we evaluate PBProbe with various bulk lengths, network configurations, and traffic models. We then perform a set of experiments to evaluate the accuracy of PBProbe on the Internet over wired and wireless links. Finally, we perform emulation and Internet experiments to verify the accuracy and speed of PBProbe on high speed links (e.g., the Gigabit Ethernet connection). The results show that PBProbe is consistently fast and accurate in the majority of test cases.
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    ABSTRACT: Knowing the capacity of an Internet path is important for efficient network utilization, pricing, and management. Using the capacity information, one can provide better TCP congestion control, multimedia streaming, P2P peer selection, and overlay structuring. Capacity estimation has been extensively studied. Though current approaches have been able to provide fast and accurate capacity estimates, they are mostly "active" in nature (ie, they utilize extra probing packets) and thus tend to be intrusive. In this paper, we propose TCP Probe, a "passive" capacity estimation extension to TCP, to accurately estimate bottleneck link capacity of an Internet path. The TCP Probe extension is packet-pair based, and it is applicable to all TCP variants. Using simulation and Internet measurements, we show that TCP Probe is able to correctly measure bottleneck capacity of a path. Moreover, we present a simple application of TCP Probe where TCP is forced to enter slow start phase when a drastic capacity change from LOW to HIGH is detected. The results show that the capacity estimate provided by TCP Probe enables it to take better advantages of the capacity increase than the original TCP. In summary, TCP Probe is simple, passive, and accurate, and it is applicable to a broad variety of TCP variants. 1 2

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