Specifying and Analyzing Virtual Network Services Using Queuing Petri Nets

TL;DR

This paper introduces a formal method using Queuing Petri Nets to specify and analyze virtual network services, enabling precise modeling of complex behaviors and aiding in optimal placement and performance evaluation.

Contribution

It presents a novel, unambiguous specification approach for virtual network services using QPNs, including a tool-based workflow for simulation and analysis.

Findings

Enhanced understanding of VNF behavior through QPN modeling

Improved network service performance analysis capabilities

Potential for better VNF placement and QoS management

Abstract

For optimal placement and orchestration of network services, it is crucial that their structure and semantics are specified clearly and comprehensively and are available to an orchestrator. Existing specification approaches are either ambiguous or miss important aspects regarding the behavior of virtual network functions (VNFs) forming a service. We propose to formally and unambiguously specify the behavior of these functions and services using Queuing Petri Nets (QPNs). QPNs are an established method that allows to express queuing, synchronization, stochastically distributed processing delays, and changing traffic volume and characteristics at each VNF. With QPNs, multiple VNFs can be connected to complete network services in any structure, even specifying bidirectional network services containing loops. We propose a tool-based workflow that supports the specification of network services and the automatic generation of corresponding simulation code to enable an in-depth analysis of their behavior and performance. In a case study, we show how developers can benefit from analysis insights, e.g., to anticipate the impact of different service configurations. We also discuss how management and orchestration systems can benefit from our clear and comprehensive specification approach and its extensive analysis possibilities, leading to better placement of VNFs and improved Quality of Service.