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Propositions for a robust and inter-operable eXplicit Control Protocol on heterogeneous high speed networks

Dino Martín Lopez Pacheco 1, 2
1 RESO - Protocols and softwares for very high-performance network
Inria Grenoble - Rhône-Alpes, ENS Lyon - École normale supérieure - Lyon, CNRS - Centre National de la Recherche Scientifique : UMR5668
Abstract : The congestion control protocols aim to fairly share the network resources between users and avoid congestion. In this thesis, we have first compared the performance of different protocols in networks where the bandwidth varies over time (Variable Bandwidth Environments -- VBE --) due to the aggregation/disaggregation of flows and/or the presence of Quality of Service (QoS) mechanisms.

Thus, we have shown that the routers-assisted protocols providing Explicit Rate Notification (ERN protocols) provide higher fairness level and avoid congestion better than End-to-End (E2E) protocols (e.g., TCP-based protocols). However, the absence of inter-operability of ERN protocols with the non-ERN routers (like the DropTail routers) and the E2E congestion control protocols (like TCP) prevent the deployed of ERN protocols in current networks.

In order to solve the problems of inter-operability of ERN protocols with non-ERN routers, we have proposed a solution which detects the set of non-ERN router between two ERN routers, estimates the available bandwidth in that set of non-ERN routers, and creates a virtual router that computes a feedback reflecting the estimated available bandwidth.

Regarding the inter-operability problems of ERN protocols with E2E protocols, we have proposed a solution which provides friendliness between both kind of protocols. The mechanisms implemented by our friendliness solution can be divided in two steps. First, our solution estimates the resources needed by the ERN and E2E protocols in terms of bandwidth. Later, our friendliness solution randomly drops packets belonging to the E2E flows, with a probability updated on base of the results found in the first step.

Since the success of ERN protocols depends on the information about the state of the network provided by the routers (the feedback), in this thesis we have studied the behavior of ERN protocols in scenarios where a percentage of the feedback has been lost. Such studies show that feedback losses in networks with VBE may lead to a chaotic behavior of ERN flows. Therefore, we have proposed a new architecture for ERN protocols which improves the responsiveness and the robustness of ERN flows in networks with VBE and feedback losses.

The set of mechanisms and solutions presented in this thesis, easy to apply to several ERN protocols, have been implemented and validated on the eXplicit Control Protocol (XCP). Thus, we have shown that our solutions surmount the inter-operability problems of ERN protocols in a wide range of network topologies and scenarios.

This thesis has provided the basis for creating an ERN protocol able to be gradually deployed in current heterogeneous large bandwidth-delay product networks, where users frequently need to move very large amount of data (e.g., Data Grid).
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Contributor : Dino Martín Lopez Pacheco <>
Submitted on : Friday, July 11, 2008 - 10:59:37 AM
Last modification on : Wednesday, November 20, 2019 - 2:34:18 AM
Long-term archiving on: : Friday, May 28, 2010 - 11:26:11 PM


  • HAL Id : tel-00295072, version 1



Dino Martín Lopez Pacheco. Propositions for a robust and inter-operable eXplicit Control Protocol on heterogeneous high speed networks. Networking and Internet Architecture [cs.NI]. Ecole normale supérieure de lyon - ENS LYON, 2008. English. ⟨tel-00295072⟩



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