SDN and NFV: A New Dimension to Virtualization

Software-defined network (SDN) and network function virtualization (NFV) are two technology trends that have revolutionized network management, particularly in highly distributed networks that are used in public, private, or hybrid cloud services. SDN and NFV technologies, when combined, simplify the deployment of network resources, lower capital and operating expenses, and offer greater network flexibility. The increasing usage of NFV is one of the primary factors that make SDN adoption attractive. The integration of these two technologies; SDN and NFV, offer a complementary service, with NFV delivering many of the real services controlled in an SDN. While SDN is focused on the control plane, NFV optimizes the actual network services that manage the data flows. Devices such as routers, firewalls, and VPN terminators are replaced with virtual devices that run on commodity hardware in NFV physical networking. This resembles the 'as-a-service' typical model of cloud services in many aspects. These virtual devices can be accessed on-demand by communication, network, or data center providers.

This book illustrates the fundamentals and evolution of SDN and NFV and highlights how these two technologies can be integrated to solve traditional networking problems. In addition, it will focus on the utilization of SDN and NFV to enhance network security, which will open ways to integrate them with current technologies such as IoT, edge computing and blockchain, SDN-based network programmability, and current network orchestration technologies. The basics of SDN and NFV and associated issues, challenges, technological advancements along with advantages and risks of shifting networking paradigm towards SDN are also discussed. Detailed exercises within the book and corresponding solutions are available online as accompanying supplementary material.

軟體定義網路（SDN）和網路功能虛擬化（NFV）是兩個革命性的技術趨勢，尤其在公有、私有或混合雲服務中使用的高度分散的網路管理中。當SDN和NFV技術結合時，可以簡化網路資源的部署，降低資本和運營成本，並提供更大的網路靈活性。NFV的使用增加是使SDN採用變得有吸引力的主要因素之一。這兩種技術的整合，SDN和NFV，提供了一種互補的服務，其中NFV提供了在SDN中控制的許多實際服務。雖然SDN專注於控制平面，但NFV優化了管理數據流的實際網路服務。路由器、防火牆和VPN終結器等設備被在NFV物理網路上運行的虛擬設備所取代，這與許多雲服務的“即服務”典型模型相似。這些虛擬設備可以根據通信、網路或數據中心提供商的需求隨時訪問。

本書介紹了SDN和NFV的基礎和演進，並強調了如何將這兩種技術整合起來解決傳統網路問題。此外，本書還將重點介紹如何利用SDN和NFV增強網路安全，並開展與當前技術（如物聯網、邊緣計算和區塊鏈）、基於SDN的網路可編程性以及當前的網路編排技術的整合。還討論了SDN的基礎知識和NFV相關問題、挑戰、技術進展以及將網路範式轉向SDN的優勢和風險。本書內還提供了詳細的練習題和相應的解答，並提供了在線補充材料。