(嗖嗖声) (whooshing)
这是多个视频中的一个 - [Instructor] This is one of multiple videos
讨论 SDN，网络可编程性, discussing SDN, network programmability,
网络自动化、覆盖及相关技术。 network automation, overlays and related technologies.
另一个非常流行的软件定义网络潮流 Another very popular software-defined networking trend
是软件定义的广域网。 is software-defined WAN.
下面是思科收购另一家公司的一个例子 Here's an example of Cisco purchasing another company
特别是他们的 SD-WAN 解决方案。 specifically for their SD-WAN solution.
思科已经有了一个叫做 IWAN 的产品, Cisco already have a product called IWAN,
因此，思科现在又购买了一款新产品 so Cisco have now purchased a additional product
在这个地方。 in this space.
应用了软件定义网络的概念 SD-WAN applies software-defined networking concepts
到广域网或广域网。 to the WAN or wide area network.
在过去，公司使用帧中继 In the past, companies used Frame Relay
因为他们有广泛的区域联系。 for their wide area connections.
然后他们转移到了 MPLS。 Then they moved to MPLS.
如今，互联网已经足够好了 These days, the internet is good enough
你可以发送大量的流量 that you can send a lot of traffic
通过互联网或公共云 across the internet or public cloud
而不是通过一个更昂贵的 MPLS 网络发送。 rather than sending it across a more expensive MPLS network.
Sdx 中心有这个定义 SDX Central have this definition
软件定义的广域网或者 SD-WAN that software-defined wide area network or SD-WAN
是 SDN 技术的一个具体应用 is a specific application of SDN technologies
应用于广域网连接 applied to WAN connections
用于连接企业网络。 which are used to connect enterprise networks.
所以，SD-WAN 的想法 So, the idea with SD-WAN
交通是可以动态控制的 is that traffic can be dynamically controlled
以及通过 MPLS 网络发送的一些流量 and some traffic sent through the MPLS network
而其他流量则是动态发送的 while other traffic is sent dynamically
通过网络云。 through the internet cloud.
而不是使用静态 vpn Rather than using static VPNs
还有原则型路由, and policy-based routing,
控制器可以集中使用 a controller can be used centrally
通过 MPLS 网络转发一些流量。 to forward some traffic across the MPLS network.
例如，加载延迟应用程序 So, as an example, load latency applications
比如语音和视频 such as voice and video
可以通过 MPLS 网络发送 could be sent through the MPLS network
而其他交通工具 whereas other traffic
可以通过互联网转发。 could be forwarded across the internet.
以集中式控制器为例 Centralized controllers as an example
会有更好的视野 will have better visibility
应用程序遍历广域网。 of applications traversing the WAN.
它们可以阻止非对称路由 They can stop asymmetric routing
动态转发数据流 and dynamically forward traffic
通过不同的网络路径。 across different network paths.
Sd-wan 解决方案可以使用覆盖 An SD-WAN solution could use an overlay
通过各种隧道进行交通 where traffic is sent through various tunnels
是动态形成的 that are dynamically formed
但最终的结果是 but the net result is that it's easier
管理流量的转发 to manage the forwarding of traffic
通过广域网。 across wide area networks.
它可以通过图形用户界面来控制 It can be controlled through a graphical user interface
以及易于使用的界面 and an easy-to-use interface
更好的管理 allowing for better management
更少的资源和节省公司的资金 and less resources and saving companies' money
通过昂贵的链路传送一些流量 by sending some traffic across expensive links
但是其他通过廉价连接的交通。 but other traffic across less expensive links.