Many techniques have been proposed in the last few years to address performance degradations in end-to-end congestion control. Although these techniques require parameter tuning to operate in different congestion scenarios, they miss the challenging target of both minimizing network delay and keeping goodput close to the network capacity. In this paper we propose a new mechanism, called Active Window Management (AWM), which addresses these targets by stabilizing the queue length in the network gateways. AWM acts on the Advertised Window parameter in the TCP segment carrying the acknowledge, but it does not affect the TCP protocol. The proposed technique is implemented in the network access gateways, that is, in the gateways through which both the incoming and outgoing packets related to a given TCP connection are forced to go, whatever the routing strategy used in the network. We show that when the access gateways implementing AWM are the bottleneck in the networks, TCP performance is very close to that of a pseudo constant bit rate protocol providing no loss, while network utilization is close to one.
Power consumption of the Information and CommunicationTechnology sector (ICT) has recently become a key challenge. In particular, actions to improve energy-efficiency of Internet Service Providers (ISPs) are becoming imperative. To this purpose, in this paper we focus on reducing the power consumption of access nodes in an ISP network, by controlling the amount of service capacity each network device has to offer to meet the actual traffic demand. More specifically, we propose a Green router (Grouter) implementing a congestion control technique named Active Window Management (AWM) coupled with a new capacity scaling algorithm named Energy Aware service Rate Tuner Handling (EARTH). The AWM characteristics allow to detect whether a waste of energy is playing out, whereas EARTH is aimed at invoking power management primitives at the hardware level to precisely control the current capacity of access nodes and consequently their power consumption. We test the benefits of the AWM-EARTH mechanism on a realistic scenario. Results show that the capacity scaling technique can save up to 70% of power consumption, while guaranteeing Quality of Service and traffic demand constraints.
In the last few years, network “softwarization” is gaining increasing popularity to achieve dynamicity and flexibility. Cloud computing, as well as the new paradigms of Software Defined Networking (SDN) and Network Functions Virtualization (NFV), are supporting this evolution. However, the need to move services closer to users to guarantee low latency in the service fruition on one hand, and the trend to support personalization of services on the other, are stimulating the migration of services toward edge nodes (in the so-called “fog computing” fashion). This is the target of the INPUT platform, proposed in the INPUT project to support Future Internet personal cloud services in a more scalable and sustainable way, and with innovative added-value capabilities. The INPUT platform enables next-generation cloud applications to go beyond classical service models, and even replaces physical Smart Devices, usually placed in users’ homes (e.g., set-top-boxes, etc.), with virtual entities, providing them to users “as a Service.” In this paper, we present the INPUT paradigm and discuss a relevant use case – namely, the virtual Set-Top-Box – adopted to prove the feasibility of the softwarized SDN/NFV paradigm jointly with the fog-computing approach for the support of personal cloud services. The INPUT platform is also compared with a legacy approach to evaluate the gain in terms of quality of experience (QoE) for both static and mobile users
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