SDN

Software Defined Networking (SDN) are a set of techniques related to the area of computer networks, whose objective is to facilitate the implementation and implementation of network services in a deterministic, dynamic and scalable way, preventing the network administrator to manage such services at low level. All this is achieved by separating the control plane (software) from the data plane (hardware).

SDN architecture



Container technology (left) can reduce the amount of resources used when compared with virtualizing using VMs (right).

 

In the SDN architecture, the splitting of the control and data forwarding functions is referred to as “disaggregation,” because these pieces can be sourced separately, rather than deployed as one integrated system. This architecture gives the applications more information about the state of the entire network from the controller, as opposed to traditional networks where the network is application aware.

 

SDN architectures generally have three components or groups of functionalities:

• SDN Applications: SDN Applications are programs that communicate behaviors and needed resources with the SDN Controller via application programming interface (APIs). In addition, the applications can build an abstracted view of the network by collecting information from the controller for decision-making purposes. These applications could include networking management, analytics, or business applications used to run large data centers. For example, an analytics application might be built to recognize suspicious network activity for security purposes.


• SDN Controller: The SDN Controller is a logical entity that receives instructions or requirements from the SDN Application layer and relays them to the networking components. The controller also extracts information about the network from the hardware devices and communicates back to the SDN Applications with an abstract view of the network, including statistics and events about what is happening.


• SDN Networking Devices: The SDN networking devices control the forwarding and data processing capabilities for the network. This includes forwarding and processing of the data path.

The SDN Architecture is:

• Directly programmable: Network control is directly programmable because it is decoupled from forwarding functions.


• Agile: Abstracting control from forwarding lets administrators dynamically adjust network-wide traffic flow to meet changing needs.


• Centrally managed: Network intelligence is (logically) centralized in software-based SDN controllers that maintain a global view of the network, which appears to applications and policy engines as a single, logical switch.


• Programmatically configured: SDN lets network managers configure, manage, secure, and optimize network resources very quickly via dynamic, automated SDN programs, which they can write themselves because the programs do not depend on proprietary software.


• Open standards-based and vendor-neutral: When implemented through open standards, SDN simplifies network design and operation because instructions are provided by SDN controllers instead of multiple, vendor-specific devices and protocols.

 

PDF document: SDN - Vega, Ernesto