On-Line Path Computation and Function Placement in SDNs

Guy Even, Moti Medina*, Boaz Patt-Shamir

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We consider service requests that arrive in an online fashion in Software-Defined Networks (SDNs) with network function virtualization (NFV). Each request is a flow with a high-level specification of routing and processing (by network functions) requirements. Each network function can be performed by a specified subset of servers in the system. The algorithm needs to decide whether to reject the request, or accept it and with a specific routing and processing assignment, under given capacity constraints (solving the path computation and function placement problems). Each served request is assumed to “pay” a pre-specified benefit and the goal is to maximize the total benefit accrued. In this paper we first formalize the problem, and propose a new service model that allows us to cope with requests with unknown duration without preemption. The new service model augments the traditional accept/reject schemes with a new possible response of “stand by.” We also present a new expressive model to describe requests abstractly using a “plan” represented by a directed graph. Our algorithmic result is an online algorithm for path computation and function placement that guarantees, in each time step, throughput of at least a logarithmic fraction of a (very permissive) upper bound on the maximal possible benefit.

Original languageEnglish
Pages (from-to)306-325
Number of pages20
JournalTheory of Computing Systems
Volume63
Issue number2
DOIs
StatePublished - 15 Feb 2019

Keywords

  • Online algorithms
  • Routing
  • Software defined networks
  • Throughput maximization
  • Unknown durations

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