先决条件 – 局域网和广域网
1. 传统广域网：
传统网络完全基于硬件网络设备，主要依靠多协议标签交换 (MPLS) 来实现弹性和高效的网络流量。许多硬件设备与专有电路一起安装，以将 IP 服务路由到其预期客户。 IT 团队付出了很多努力来管理网络，因为它涉及安装的底层硬件层。
传统网络的扩展很困难，因为它需要适当的高级规划以及所需的网络基础设施来设置和运行。传统连接许多局域网 (LAN) 和虚拟专用网 (VPN)，它仅限于企业、分支机构和数据中心。它允许优先考虑网络上的数据、语音和视频流量。安全问题和管理困难是当今传统广域网的主要问题。
2. 软件定义广域网(SD WAN)：
SD WAN 代表软件定义的广域网，它是一种管理广域网的软件定义的方法。在 SD WAN 中，软件控制着从连接到管理和提供服务的一切。它是一种结合了 MPLS、LTE 和宽带连接等传统 WAN 技术的虚拟网络方法。
SD WAN 非常适合全球企业，因为它提供了更好、更安全的应用程序性能以及优化的云连接和简化的管理。在以云为中心的世界中，SD WAN 比传统 WAN 更可取。利用软件定义网络 (SDN) 来帮助确定最佳路由方式。
传统广域网和SD WAN的区别：
| S.No. | TRADITIONAL WAN | SD WAN |
|---|---|---|
| 01. | Traditional WAN provides a conventional approach of managing Wide Area Network. | Software Defined WAN provides a software defined approach of managing Wide Area Network. |
| 02. | It fails to provide a better flexibility in WAN management. | It provides a better flexibility in WAN management. |
| 03. | New configuration and scale up takes very high time. | New configuration and scale up takes very low time. |
| 04. | In traditional network configuration is done by skilled resources means requires human intervention. | In SD WAN network configuration is done by automatically without requiring human intervention. |
| 05. | It does not provide low cost and high speed connectivity. | It provides low cost and high speed connectivity. |
| 06. | It provides low performance for the application in cloud as it connects to intermediate hub then to cloud. | It provides high performance for the application in cloud as it directly access applications hosted in cloud. |
| 07. | In traditional WAN, Data centers are limited in their capacity to deal with incoming connections to multiple cloud platforms. | In Software Defined WAN, Data centers are not limited based on underlying hardware that comprises the network. |
| 08. | Traditional WAN increases the the complexity associated with management, configuration and infrastructure arrangement of WANs. | Software Defined WAN simplifies the complexity associated with management, configuration and infrastructure arrangement of WANs. |
| 09. | Traditional WAN solutions may not provides secure VPN like SD WAN and also fails to fully integrate additional features like firewall, Wan Optimization, SWG etc. | SD WAN solutions provides secure VPN than traditional WAN and also integrates additional features like firewall, Wan Optimization, SWG etc. |
| 10. | Traditional WAN is secure over an MPLS connection as packets that are sent are private as well as packet loss is avoided. | SD WAN provides a secured data traffic through end-to-end encryption over a virtual private network (VPN) connection also integrates additional security features. |