Beyond socket options: making the Linux TCP stack truly extensible

The Transmission Control Protocol (TCP) is one of the most important protocols in today's Internet. Its specification and implementations have been refined for almost forty years. The Linux TCP stack is one of the most widely used TCP stacks given its utilisation on servers and Android smartphones and tablets. However, TCP and its implementations evolve very slowly. In this paper, we demonstrate how to leverage the eBPF virtual machine that is part of the recent versions of the Linux kernel to make the TCP stack easier to extend. We demonstrate a variety of use cases where the eBPF code is injected inside a running kernel to update or tune the TCP implementation. We first implement the TCP User Timeout Option. Then we propose a new option that enables a client to request a server to use a specific congestion control scheme. Our third extension is a TCP option that sets the initial congestion window. We then demonstrate how eBPF code can be used to tune the acknowledgment strategy.Comment: 9 pages, 8 figure

A distributed end-to-end overload control mechanism for networks of SIP servers.

The Session Initiation Protocol (SIP) is an application-layer control protocol standardized by the IETF for creating, modifying and terminating multimedia sessions. With the increasing use of SIP in large deployments, the current SIP design cannot handle overload effectively, which may cause SIP networks to suffer from congestion collapse under heavy offered load. This paper introduces a distributed end-to-end overload control (DEOC) mechanism, which is deployed at the edge servers of SIP networks and is easy to implement. By applying overload control closest to the source of traf?c, DEOC can keep high throughput for SIP networks even when the offered load exceeds the capacity of the network. Besides, it responds quickly to the sudden variations of the offered load and achieves good fairness. Theoretic analysis and extensive simulations verify that DEOC is effective in controlling overload of SIP networks

Bandwidth Estimation for Admission Control in MANET: Review and Conceptual MANET Admission Control Framework

The widespread of wireless mobile network have increased the demand for its applications. Providing a reliable QoS in wireless medium, especially mobile ad-hoc network (MANET), is quite challenging and remains an ongoing research trend. One of the key issues of MANET is its inability to accurately predict the needed and available resources to avoid interference with already transmitting traffic flow. In this work, we propose a resource allocation and admission control (RAAC) solution. RAAC is an admission control scheme that estimates the available bandwidth needed within a network, using a robust and accurate resource estimation technique. Simulation results obtained show that our proposed scheme for MANET can efficiently estimate the available bandwidth and outperforms other existing approaches for admission control with bandwidth estimation

End-to-end congestion detection and avoidance in wide area networks

As human dependence on wide area networks like the Internet increases, so does contention for the network's resources. This contention has noticeably affected the performance of these networks, reducing their usability. This dissertation addresses this problem in two ways. First, it describes TCP Vegas, a new implementation of TCP that is distinguished from current TCP implementations by containing a new congestion detection and avoidance mechanism. This mechanism was designed to work in currently available wide area networks and achieves between 37% and 71% better throughput on the Internet, with one-fifth to one-half the losses, as compared to the current implementation of TCP. Second, it describes x-Sim, a network simulator based on the x-kernel, that is able to simulate the topologies and traffic patterns of large scale networks. The usefulness of the simulator to analyze and debug network components is illustrated throughout this dissertation