Joint Multi-dimensional Resources Allocation For NFV Service Chaining In Inter-datacenter Optical Networks

Network Function Virtualization(NFV)can realize virtual network function(VNF)by using generalized commercial off-the-shelf equipments in datacenters(DC)to re-place the special-purpose network elements,and to achieve the flexible deployment.Hence,datacenter should schedule the IT resources to deploy VNF to increase resources utilization.The data-rate of a traffic flow may change when it goes through an NFV ser-vice chaining,the traffic flow in inter-DC can exhibit high throughput and high bursti-ness,which challenge the physical infrastructure.Elastic Optical Network(EON)re-alize agile bandwidth management and provide huge spectrum capacity in the optical layer,which is a promising physical infrastructure for supporting inter-DC EON to de-ploy NFV service chains,also,the optical service chain has low power consumption.But,this agile feature require the network control and management should allocate net-work resources efficiently.Firstly,we discuss the multi-dimensional resources fragmentation in Inter-DC EON while provisioning basic component of NFV service chaining.To address this issue,we investigates the problem of joint defragmentation(DF)for the spectrum and IT re-sources in Inter-DC EON.Specifically,we re-optimize the allocations of multi-dimensional resources jointly with complexity-controlled network reconfigurations.For the joint DF operation,we first study the request selection process and proposed a joint selection strategy that can perform the spectrum-and IT-oriented selections adaptively accord-ing to the network status.Then,we formulate a mixed integer linear programming model and design several heuristics to tackle the problem of network reconfiguration in the joint DF.Simulation results demonstrate that the proposed joint DF algorithms can significantly reduce the blocking probability in Inter-DC EON by consolidating the spectrum and IT resource usages effectively.Secondly,we study how to allocate spectrum and IT resources jointly for realizing efficient NFV service chaining in Inter-DC EON.We first formulate an integer linear programming model to solve the problem,and then several algorithms are proposed,which including a longest common subsequence based heuristic algorithm.The pro-posed algorithms are evaluated with extensive simulations,simulation results indicate that the proposed algorithms can arrange the spectrum utilization in a much more load-balanced manner and reuse the deployed VNFs efficiently.