Towards Wireless Virtualization for 5G Cellular Systems

Although it has been defined as one of the most promising key enabling technologies for the forthcoming fifth generation cellular networks, wireless virtualization still has several challenges remaining to be addressed. Amongst those, resource allocation, which decides how to embed the different wireless virtual networks on the physical relying infrastructure, is the one receiving maximum attention. This project aims at finding the optimal resource allocation for each virtual network, in terms of channel resources, power levels and radio access technologies so that the data rate requested by each virtual network can be guaranteed and the global throughput efficiency can be maximized.Aunque haya sido definida como una de las tecnologías clave para el desarrollo de la nueva generación de sistemas móviles, la virtualización del acceso radio aún tiene muchos retos a investigar. Entre ellos, la distribución de los recursos, que tiene por objetivo encontrar el mejor encaje de las distintas redes virtuales en la infraestructura física que comparten, es el que está recibiendo la mayor atención. Este proyecto, tiene por objetivo encontrar la repartición óptima de los recursos, tanto a nivel de canal como de potencia y de tecnologías de acceso radio, para que los requisitos de las redes virtuales puedan ser garantizadas y la eficiencia global sea maximizada.Malgrat ha estat definida com una de les tecnologies claus de cara al desenvolupament de la propera cinquena generació de xarxes mòbils, la virtualització de l'accés radio encara té molts reptes oberts a fer front. Entre ells, la distribució de recursos, que té per objectiu buscar el millor encaix de les diferents xarxes virtuals en la infraestructura física que comparteixen, és la que està centrant la màxima atenció. Aquest projecte té per objectiu aconseguir la repartició òptima de recursos, pel que fa al canal, als nivells de potència i a les tecnologies radio disponibles, de manera que els requisits de cada xarxa virtual puguin ser garantits i que l'eficiència global pugui ser maximitzada

Everything Matters in Programmable Packet Scheduling

Programmable packet scheduling allows the deployment of scheduling algorithms into existing switches without need for hardware redesign. Scheduling algorithms are programmed by tagging packets with ranks, indicating their desired priority. Programmable schedulers then execute these algorithms by serving packets in the order described in their ranks. The ideal programmable scheduler is a Push-In First-Out (PIFO) queue, which achieves perfect packet sorting by pushing packets into arbitrary positions in the queue, while only draining packets from the head. Unfortunately, implementing PIFO queues in hardware is challenging due to the need to arbitrarily sort packets at line rate based on their ranks. In the last years, various techniques have been proposed, approximating PIFO behaviors using the available resources of existing data planes. While promising, approaches to date only approximate one of the characteristic behaviors of PIFO queues (i.e., its scheduling behavior, or its admission control). We propose PACKS, the first programmable scheduler that fully approximates PIFO queues on all their behaviors. PACKS does so by smartly using a set of strict-priority queues. It uses packet-rank information and queue-occupancy levels at enqueue to decide: whether to admit packets to the scheduler, and how to map admitted packets to the different queues. We fully implement PACKS in P4 and evaluate it on real workloads. We show that PACKS: better-approximates PIFO than state-of-the-art approaches and scales. We also show that PACKS runs at line rate on existing hardware (Intel Tofino).Comment: 12 pages, 12 figures (without references and appendices

Towards Wireless Virtualization for 5G Cellular Systems

Although it has been defined as one of the most promising key enabling technologies for the forthcoming fifth generation cellular networks, wireless virtualization still has several challenges remaining to be addressed. Amongst those, resource allocation, which decides how to embed the different wireless virtual networks on the physical relying infrastructure, is the one receiving maximum attention. This project aims at finding the optimal resource allocation for each virtual network, in terms of channel resources, power levels and radio access technologies so that the data rate requested by each virtual network can be guaranteed and the global throughput efficiency can be maximized.Aunque haya sido definida como una de las tecnologías clave para el desarrollo de la nueva generación de sistemas móviles, la virtualización del acceso radio aún tiene muchos retos a investigar. Entre ellos, la distribución de los recursos, que tiene por objetivo encontrar el mejor encaje de las distintas redes virtuales en la infraestructura física que comparten, es el que está recibiendo la mayor atención. Este proyecto, tiene por objetivo encontrar la repartición óptima de los recursos, tanto a nivel de canal como de potencia y de tecnologías de acceso radio, para que los requisitos de las redes virtuales puedan ser garantizadas y la eficiencia global sea maximizada.Malgrat ha estat definida com una de les tecnologies claus de cara al desenvolupament de la propera cinquena generació de xarxes mòbils, la virtualització de l'accés radio encara té molts reptes oberts a fer front. Entre ells, la distribució de recursos, que té per objectiu buscar el millor encaix de les diferents xarxes virtuals en la infraestructura física que comparteixen, és la que està centrant la màxima atenció. Aquest projecte té per objectiu aconseguir la repartició òptima de recursos, pel que fa al canal, als nivells de potència i a les tecnologies radio disponibles, de manera que els requisits de cada xarxa virtual puguin ser garantits i que l'eficiència global pugui ser maximitzada

On offloading control plane applications to the data plane

One of the most active areas in computer networking is Software Defined Networking (SDN). SDN separates the two core functions of a network element (e.g., router): the control-plane and the data-plane. Traditionally both these functions were implemented on the same device; SDN decouples them, and allows multiple control-plane implementations for managing each data-plane. Despite the additional flexibility brought by separating these functions, SDN still assumes that the behavior of the network data-plane is fixed. This is a significant impediment to innovation. As a reacScheduling is one of the main active players in the quest for programmable networks. Despite the numerous research efforts that have been dedicated in latest years, not a single scheduling framework has resulted to be powerful enough to outperform the rest in a wide variety of scenarios. A new perspective to the problem has been therefore recently brought up, which suggests abandoning the pursue of a global scheduling solution, and moving into a more flexible and programmable conception. Network equipment should be designed to support different algorithms, from which it could select and configure the most appropriate one at each moment to face the instantaneous requirements of the dynamic nature in traffic demands. With the idea of making scheduling more programmable, new abstractions have been already defined, based on decoupling the process in two steps: a programmable-pipeline determining the order in which packets should be transmitted, and a fixed-logic push-in first-out (PIFO) queue draining packets in the desired arrangement. While PIFO abstraction is innovative and deeply promising, its hardware implementation is not straightforward. To the intrinsic difficulties of such a complex queuing design, adds the fact that ASIC production is by definition a multi-year process, propelling the release of a hardware built-in PIFO too far from expectations. Aiming to fill this temporal problem, in this thesis, a novel approach is proposed. Would it be possible to achieve a PIFO-behavior with the current resources available in nowadays networks? By trying to answer this question, we will embark in a journey that will span from revising the first quality of service proposals introduced at early networks, to discussions on how to reach predictability in potential future generations. Altogether, with the focus centered on squeezing the maximum benefit from the recent advances in network programmability, with special emphasis in the latest proceedings for programmable forwarding data planes

QVISOR: Virtualizing Packet Scheduling Policies

The concept of programmable packet scheduling has been recently introduced, enabling the programming of scheduling algorithms into existing data planes without requiring new hardware designs. Notably, several programmable schedulers have been proposed, which are capable of running directly on existing commodity switches. Unfortunately, though, their focus has been limited to single-tenant traffic scheduling: i.e., scheduling all incoming traffic following one single scheduling policy (e.g., pFabric to minimize flow completion times). In this paper, we emphasize the fact that today’s networks are heterogeneous: they are shared by multiple tenants, who run applications with different performance requirements. As such, we introduce a new research challenge: how can we extend scheduling programmability to multi-tenant policies? We envision QVISOR, a scheduling hypervisor that enables multi-tenant programmable scheduling on existing switches. With QVISOR, tenants program the scheduling policies for their traffic flows; operators define how tenants should share the available resources; and QVISOR does the rest: deploying the scheduling policies into the underlying hardware