Autonomic resource arbitration and service-continuable network function migration along service function chains

Service function (SF) chaining enables network operators and infrastructure providers to flexibly orchestrate virtualized network functions (NFs) at various places on software defined virtual networks. Meanwhile, with the rapid prevalence of Internet-of-Things (IoT) applications and mobile network services, quality-of-service (QoS) requirements are getting increasingly diverse and network traffic volume and pattern are varying rapidly. The time-varying network traffic requires the infrastructure provider to dynamically adjust the appropriate amount of computational resources (e.g. CPU) assigned to an NF to efficiently process the traffic in the SF chaining infrastructure. In this paper, to adequately allocate CPU resources (available in limited amount) to virtual networks (VNs) requiring to satisfy diverse QoS levels in response to traffic variation without manual operations, we propose autonomic arbitration of CPU resources along SF chains which combines two CPU resource adjustment methods: The first method performs resource arbitration among VNs within a node, and the second method migrates NFs among nodes within a VN. These methods autonomically adjust the amount of CPU resource allocated to each NF so that over utilization of CPU can be avoided as much as possible. Moreover, during the autonomic resource adjustments in SF chains, the proposed methods are able to maintain communication paths on the substrate network so that the service is not interrupted at all. We also propose differentiated resource allocation for QoS differentiation and transferable resource searching. Through computer simulation, we verify that our autonomic resource adjustment methods can reduce the occurrence of CPU-saturation by more than 90%.

I. Introduction

Virtualizing network infrastructures [1]–[5] and/or network functions (NFs) [6] [7] enables virtual networks (VNs) on top of the same underlying physical infrastructure to be isolated from each other by allocating network resources separately. Virtual network operators (VNOs) have been emerging rapidly in the telecommunication market for virtual network service provisioning. Mobile VNOs have already been providing virtual network services by leasing physical lines and servers from other carriers. Likewise, network function virtualization (NFV) techniques enable us to implement all functions of the traditional network equipment in software on virtualization infrastructures consisting of general-purpose servers, at reduced CAPEX/OPEX because multiple NFs can be installed on a common physical machine (i.e. consolidating physical network equipment). NFs include firewall, deep packet inspection (DPI), network address translation (NAT), content caches, multimedia transcoding, and so on.