RDNA: Residue-Defined Networking Architecture Enabling Ultra-Reliable Low-Latency Datacenters

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/userguides/explore-bristol-research/ebr-terms/ 1932-4537 (c)Abstract-Datacenter (DC) design has been moved towards the edge computing paradigm motivated by the need of bringing cloud resources closer to end users. However, the Software Defined Networking (SDN) architecture offers no clue to the design of Micro Datacenters (MDC) for meeting complex and stringent requirements from next generation 5G networks. This is because canonical SDN lacks a clear distinction between functional network parts, such as core and edge elements. Besides, there is no decoupling between the routing and the network policy. In this paper, we introduce Residue Defined Networking Architecture (RDNA) as a new approach for enabling key features like ultra-reliable and low-latency communication in MDC networks. RDNA explores the programmability of Residues Number System (RNS) as a fundamental concept to define a minimalist forwarding model for core nodes. Instead of forwarding packets based on classical table lookup operations, core nodes are tableless switches that forward packets using merely remainder of the division (modulo) operations. By solving a residue congruence system representing a network topology, we found out the algorithms and their mathematical properties to design RDNA's routing system that (i) supports unicast and multicast communication, (ii) provides resilient routes with protection for the entire route, and (iii) is scalable for 2-tier Clos topologies. Experimental implementations on Mininet and NetFPGA SUME show that RDNA achieves 600 ns switching latency per hop with virtually no jitter at core nodes and submillisecond failure recovery time.

XOR-based Source Routing

“…A simple method to generate the encoded path is to concatenate the interface labels. More elaborated strategies presented in [13] and [10] encode the path into an integer number. The routers recover their information by computing the residue of this integer modulo a prime number.…”

“…In this study, we choose to select and focus on two recent competitive works that provide path optimization techniques to minimize the size of a path label encoded inside packets. We will mainly discuss XSR against these two solutions proposed respectively in 2017 [9] and in 2018 [10]. In the latter, the authors propose a whole architecture, referred to as RDNA, that lays on modular arithmetic to compute a label number to identify (following a reverse operation) the output switch port considering a unique router ID [10].…”

RDNA Balance: Balanceamento de Carga por Isolamento de Fluxos Elefante em Data Centers com Roteamento na Origem

“…Seguindo os princípios das Redes Definidas por Software, (do inglês Software Defined Networking -SDN), a RDNAé composta por três elementos representados na Figura 1: i) o controlador RDNA, que consiste em um controlador centralizado capaz de configurar políticas e monitorar os switches da rede; ii) switches de borda, que são os responsáveis por inserir nos pacotes os identificadores das rotas usando a codificação possibilitada pelo Teorema Chinês dos Restos [Liberato et al 2018] e; iii) os switches de núcleo, que não possuem tabelas e realizam o encaminhamento dos pacotes realizando operações de módulo. A operação de móduloé realizada entre o ID da rota presente no cabeçalho do pacote (inserido no pacote pelo switch de borda) e o identificador do switch de núcleo.…”

“…Estes resultados serão apresentados na Seção 4. Análises de escalabilidade do encaminhamento e mais detalhes do roteamento são encontrados em [Liberato et al 2018].…”

“…Dentre as diversas alternativas de implementação de SSR em redes de DC destacase a RDNA (do inglês Residue Defined Network Architecture) [Liberato et al 2018], que explora características do Sistema Numérico de Resíduos (do inglês Residue Number System -RNS) para realizar o roteamento de pacotes no núcleo da rede. A principal característica da RDNAé a divisão entre os elementos de núcleo e borda da rede, onde os elementos de núcleo são mais simples e realizam apenas a tarefa de encaminhamento baseado em operações de módulo, ou seja, sem tabela.…”