Availability Evaluation of Multi-tenant Service Function Chaining Infrastructures by Multidimensional Universal Generating Function

TL;DR

This paper introduces a Multidimensional Universal Generating Function approach to evaluate and optimize the availability of multi-tenant Service Function Chaining infrastructures in NFV networks, balancing cost and reliability.

Contribution

It extends the UGF methodology to handle performance vectors and applies it to multi-tenant SFC availability analysis and redundancy optimization.

Findings

Validated in a realistic multi-tenant telecommunication scenario

Achieved steady-state availability evaluation of NFV-based service chains

Optimized redundancy to minimize costs while meeting availability targets

Abstract

The Network Function Virtualization (NFV) paradigm has been devised as an enabler of next generation network infrastructures by speeding up the provisioning and the composition of novel network services. The latter are implemented via a chain of virtualized network functions, a process known as Service Function Chaining. In this paper, we evaluate the availability of multi-tenant SFC infrastructures, where every network function is modeled as a multi-state system and is shared among different and independent tenants. To this aim, we propose a Universal Generating Function (UGF) approach, suitably extended to handle performance vectors, that we call Multidimensional UGF. This novel methodology is validated in a realistic multi-tenant telecommunication network scenario, where the service chain is composed by the network elements of an IP Multimedia Subsystem implemented via NFV. A steady-state availability evaluation of such an exemplary system is presented and a redundancy optimization problem is solved, so providing the SFC infrastructure which minimizes deployment cost while respecting a given availability requirement.