Introduction SDN before history, to understand the clean slate project
from 1969 DARPA test network start, based on Ethernet and TCP / IP, Internet, because the bulk of the design, simplicity, was a great success, and accumulated a lot of technology to address different different problems arise in the period.
At the same time there are many defects, focused on scalability, security, mobility and QoS, of course, there are many techniques to try to solve these problems, such as no inter-Domain Routing CIDR, network address translation NAT, MPLS, traffic engineering, etc. these techniques help in varying degrees throughout the Internet and a variety of proprietary protocols to today, but in any case there are always new problems, the reason is because these existing technologies are repaired in-house network framework. A growing number of researchers believe that redefine the network architecture may be the ultimate solution, and this scheme is called clean slate scheme.
clean has broad and narrow sense on the internet research, refers to the next generation network NGN projects in a broad sense, the agreement is a clean slate by a Stanford University professor Nick mckeown laboratory research programs, SDN was born in the narrow sense of the clean slate program in.
SDN is recognized as the birthplace of Stanford University, originated in the campus network, to carry forward the data center, is the pioneer of a Stanford graduate student named Martin casado exact pioneer OpenFlow is the pioneer of the concept rather than the SDN.
Furthermore, network equipment manufacturers are not allowed to reprogram the hardware, the code is written directly into a switch or router, and can not allow open source code, even if open source, and that code is complex and not easy to change, which gives users transformation and control network is a big trouble, then flexible control interface, there are always times can not be met.
So Martin casado want to set about establishing a flexible, programmable as possible to the same computer network, and wrote "called ethane network architecture," This project is part of the clean slate program. Ethane project will help understand learning OpenFlow and SDN. This project is safety-related, involving a number of security policy, the project attempts a centralized controller, so that network administrators can easily define policy-based security controls network flow, and these policies apply to a variety of network devices , thus control the security of the entire network communication. In fact, SDN subsequent development is also confirmed this point, the security area is very suitable for SDN deployments, because the security field itself stressed configuration management rather than dynamic network protocol, also stressed centralized control, this idea is very consistent with SDN.
The Casaso mentor is Nick mckeown, Mckeown spent a lot of time on OpenFlow common mode chip design for a reason. Mckeown has created a number of companies, was acquired by PMC-sierra, cisco, vmware. Mckeown attaches great importance to this project for their students, give a lot of guidance, inspired by Ethane project, Casado and Mckeown found that if Ethane design more general, traditional data networking equipment forwarding data plane and control plane routing control two functional modules separated by a centralized controller to controller interface standard of the vertebral manage network devices and a variety of configuration, the more possibilities the design, management and use of network resources will be provided, making it easier to promote innovation and development of the network.
But they did not start concept OpenFlow and SDN, but set out to develop a NOX called the controller, used for switches in the network centralized control, a by-product of NOX OpenFlow just because they found the switch focused on the use of NOX time control, if each switch can provide a unified standard interface controller, then it will be very easy to control, so OpenFlow was born.
OpenFlow several scenarios:
Campus network experimental support for communications protocols;
network management and access control;
network isolation and the VLAN;
WiFi-based mobile network;
non-IP network;
processing based on a data packet, and the like
OpenFlow-based network brings programmable features, it is further proposed the concept of SDN,
born from the SDN history can be seen, most essential feature of SDN is the separation of control and forwarding.
OpenFlow technology soon attracted the attention of the industry, many companies have been involved, March 21, 2011, Deutsche Telekom, Facebook, goole, Microsoft, Verizon, Yahoo! Launched ONF (open networking foundation) organization, aims to promote SDN, OpenFlow and began the standardization work, as more companies join the organization, ONF and SDN's influence is expanding rapidly.
Many companies saw an opportunity in which, there are many companies see the negative impact of technological change on their own brought along with competing interests, some organizations set up outside the ONF.
