1.1 The emergence of software defined network technology

The life cycle of a network system

contradiction

Cloud computing Three types of services Common requirements ：

Disadvantages of traditional network ：

• Traditional networks and their devices can only be configured 、 Not programmable
• The distributed control and management architecture of the network are tightly coupled .* Network deployment 、 Configuration and management need to be done manually on each device
  （1） Management plane ：
  Provide user access interfaces or interfaces for configuring and managing network devices
  （2） Control plane ;
  According to the configuration and management instructions , Generate the corresponding control table
  
  （3） Data plane ：—— The basis of data plane data forwarding
  According to the information given in the relevant control table of the control plane , Carry out specific message processing or forwarding .

New network architecture 、 New network design

1. Network programmability that can flexibly respond to the changes of upper application

2. [ Introduce a centralized and unified control and management layer ]
   “ Control and management ”“ Dynamic response ”

3. [ Decoupling the management plane of network equipment 、 Control plane and data plane ]

SDN Three layer network architecture of

summary ：

1.2 Software defines the development of network technology

SDN The origin of

w2005 year , National Natural Science Foundation : Network innovation experimental environment
(Global Environment Networking Innovations, GENI)
Clean-Slate project

1.3 Software defines the standardization of network technology

ONF Standardization of

·ONF Founded on 2011 year , yes SDN Standardization and industrialization are the most Main driving force .

IETF Standardization of

·IETF It is the most authoritative technology standardization organization in the world , Responsible for the R & D and formulation of Internet related technical specifications
· Network equipment manufacturers lead , More attention SDN Details of how relevant functions and technologies are implemented in the network ;

ITU-T Standardization of

·ITU-T Put forward SDN The implementation architecture of . Studied SDN The object of the scene 、 The relevant architecture is mainly for the network of operators .

ETSI Standardization of

· Set up a working group on network function virtualization Standards （NFV ISG）, Develop requirements and architectural specifications for supporting virtual functional hardware and software infrastructure, as well as guidelines for developing network functions .