DC.p4

Abstract

The P4 programming language [29,16] has been recently proposed as a high-level language to program the forwarding plane of programmable packet processors, spanning the spectrum from software switches through FPGAs, NPUs and reconfigurable hardware switches. This paper presents a case study that uses P4 to express the forwarding plane behavior of a data-center switch, comparable in functionality to single-chip shared-memory switches found in many data centers today.This case study allows us to understand how specific P4 constructs were useful in modeling specific data-center switch features. We also outline additional language constructs that needed to be added to P4 to support certain features of a data-center switch. We discuss several lessons that we learned in the process and distill these into a proposal for how P4 could evolve in the future.

RESISTING: Um Novo Mecanismo de Fast-Reroute com Distribuição de Pacotes em Switches Programáveis P4

“…É importante destacar que essa estratégia é viável porque o mecanismo ECMP, ao operar com múltiplos caminhos alternativos instalados no plano de dados, não depende de elementos externos para a recuperac ¸ão de falhas. Na linguagem P4, o FRR e o ECMP são componentes separados [Merling et al 2020, Sivaraman et al 2015, exigindo esforc ¸o de desenvolvimento para sua integrac ¸ão no plano de dados. Discutimos mais sobre a integrac ¸ão desses componentes na Sec ¸ão 4.…”

Virtual Queues for P4: A Poor Man’s Programmable Traffic Manager

“…State during execution includes information from packet headers, metadata provided by the device or computed by the program and state kept in counters, registers, and meters [26]. While the P4 language is target-independent, i.e., it abstracts from the specific hardware characteristics of the switch, a P4 compiler translates P4 programs into the instruction set of the packet processor [27]. The current specification of the language (P4 16), introduced the concept of the P4 architecture that defines the P4-programmable blocks of a target and their data plane interfaces.…”

Keeping P4 Switches Fast and Fault-free through Automatic Verification

“…The hybrid approach is highly effective, but burdens backends, static analyzers, and verification frameworks, as now these also have to take into account low-level targets. We recommend [13] and [7] on the transpiring software revolution in networking, the growing empowerment of network operators at the expense of switch vendors, and the question whether P4 will free the network from fixed-function switching interfaces (e. g. OpenFlow) by making protocol-inpedendent packet processing possible.…”