Software-Defined Network
大约 5 分钟
Software-Defined Network
- Control Plane - The brain/decision maker, focuses on how that one switch interacts with its neighbors
- Data Plane - Packet forwarder
- Management plane - carries administrative traffic.
在传统网络中，所有三个平面都在路由器和交换机的固件「firmware」中实现。
Traditional Network: Switch
Data Plane
Data Plane: processing and delivery of packets
- Based on state in routers and endpoints
- E.g.,IP,TCP,Ethernet,etc.
- Fast timescales(per-packet)
Control Plane
控制平面：建立路由器中的状态
- 确定数据包转发的方式和位置
- 路由、流量工程、防火墙状态.......
Management Plane
收集测量数据并配置设备
Networking Lag Behind
Why dose Networking Lag Behind「网络滞后」?
Networks used to be simple: Ethernet,IP,TCP....
新的 "云 "要求导致了极大的复杂性
上述机制是独立设计和部署的。
Consequences:
- Complicated "control plane"design.
- 与优雅「elegantly」的模块化「modular」 "数据平面 "形成鲜明对比。
昂贵的交换机，带有执行这些功能的专有固件！
SDN: New Concepts
- Separate
- Control plane (which decides how to handle the traffic) from
- Data plane (which forwards traffic according to decisions that the control plane makes).
- Network intelligence and state are logically centralized.
- 整合控制平面，使单一软件控制程序通过定义明确的应用程序接口（OpenFlow）控制多个数据平面元件（即路由器、交换机和其他中间设备）。
- Control program runs on commodity servers
- Decouple from specific networking hardware.
- "Programmable"data planes
- Maintain,control,and program data plane from the central entity.
- Generalized flow abstraction,open up to layers 1-7.
Network OS
- Network OS:creates a consistent, up-to-date network view.
- Runs on servers (controllers) in the network.
- Uses an open protocol (e.g.,OpenFlow)to:
- Get state information from forwarding elements
- Give control directives to forwarding elements
- OpenFlow: a protocol for remotely controlling the forwarding table of a switch or router (more to come)
What SDN really is?
With SDN->Network Industry Go Virtualized and Centralized like Cloud
