Network Function Virtualization (NFV) allows datacenters to consolidate network appliance functions onto commodity servers and devices. Currently telecommunication carriers are re-architecting their central offices as NFV datacenters that, along with SDN, help network service providers to speed deployment and reduce cost. However, it is still unclear how a carrier network shall organize its NFV datacenter resources into a coherent service architecture to support global network functional demands. This work proposes a hierarchical NFV/SDN-integrated architecture in which datacenters are organized into a multi-tree overlay network to collaboratively process user traffic flows. The proposed architecture steers traffic to a nearby datacenter to optimize user-perceived service response time. Our experimental results reveal that the 3-tier architecture is favored over others as it strikes a good balance between centralized processing and edge computing, and the resource allocation should be decided based on traffic's source-destination attributes. Our results indicate that when most traffic flows within the same edge datacenter, the strategy whereby resources are concentrated at the carrier's bottom-tier datacenters is preferred, but when most traffic flows across a carrier network or across different carrier networks, a uniform distribution over the datacenters or over the tiers, respectively, stands out from others.

中文翻译：

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NFV数据中心的分层CORD：具有成本-延迟折衷的资源分配

网络功能虚拟化（NFV）允许数据中心将网络设备功能整合到商用服务器和设备上。当前，电信运营商正在将其中心办公室重新架构为NFV数据中心，与SDN一起，可帮助网络服务提供商加快部署速度并降低成本。但是，仍然不清楚运营商网络如何将其NFV数据中心资源组织成一个一致的服务体系结构，以支持全球网络功能需求。这项工作提出了一种分层NFV / SDN集成的体系结构，其中数据中心被组织到一个多树覆盖网络中，以协作处理用户流量。提出的体系结构将流量引导到附近的数据中心，以优化用户感知的服务响应时间。我们的实验结果表明，三层体系结构在集中处理和边缘计算之间达到了很好的平衡，因此受到了青睐，并且应该根据流量的源-目的地属性确定资源分配。我们的结果表明，当大多数流量在同一个边缘数据中心内流动时，首选将资源集中在运营商的底层数据中心的策略，但是当大多数流量在运营商网络或不同运营商网络之间流动时，在服务器上进行统一分配数据中心或层上的数据中心分别脱颖而出。