Software Defined network

By: Aadarsh Sharma (152401)Nitesh Sharma (152409)ME CSE Regular 2015

• SDN most commonly means that networks are controlled by software applications and SDN controllers rather than the traditional network management consoles and commands that required a lot of administrative overhead and could be tedious to manage on a large scale.

• SDN is a framework to allow network administrators to automatically and dynamically manage and control a large number of network devices, services using high-level languages and APIs.

• SDN is to enable cloud and network engineers to respond quickly to changing business requirements via centralized control console.

What’s SDN ?

A Short History of SDN

~2004: Research on new management paradigmsRCP, 4D [Princeton, CMU,….]SANE, Ethane [Stanford/Berkeley]

2008: Software-Defined Networking (SDN)NOX Network Operating System [Nicira]OpenFlow switch interface [Stanford/Nicira]

2011: Open Networking Foundation (~69 members)Board: Google, Yahoo, Verizon, DT, Microsoft, Facebook, NTTMembers: Cisco, Juniper, HP, Dell, Broadcom, IBM,…..

2013: Latest Open Networking Summit1600 attendees, Google: SDN used for their WANCommercialized, in production use (few places)

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• Traditional networking architectures have significant limitations that must be overcome to meet modern IT requirements. Today’s network must scale to accommodate increased workloads with greater agility, while also keeping costs at a minimum. But the traditional approach has substantial limitations:

• Complexity• Inconsistent policies• Inability to scale

Why SDN ?

• The abundance of networking protocols and features for specific use cases has greatly increased network complexity. Old technologies were often recycled as quick fixes to address new business requirements. Features tended to be vendor specific or were implemented through proprietary commands.

Complexity:

• Security and quality‐of‐service (QoS) policies in current networks need to be manually configured or scripted across hundreds or thousands of network devices. This requirement makes policy changes extremely complicated for organizations to implement without significant investment in scripting language skills or tools that can automate configuration changes.

• Manual configuration is prone to error and can lead to many hours of troubleshooting to discover which line of a security policy or access control list (ACL) was entered incorrectly on a given device.

Inconsistent policies:

• As application workloads change and demand for network bandwidth increases, the IT department either needs to be satisfied with an oversubscribed static network or needs to grow with the demands of the organization.

Inability to scale:

• “What is SDN? The physical separation of the network control plane from the forwarding plane, and where a control plane controls several devices.”

Original Defination

• Makes decisions about where traffic is sent• Control plane packets are destined to or

locally originated by the router itself• The control plane functions include the system

configuration, management, and exchange of routing table information

• The route controller exchanges the topology information with other routers and constructs a routing table based on a routing protocol, for example, RIP, OSPF or BGP

• Control plane packets are processed by the router to update the routing table information.

• It is the Signaling of the network

Control Plane

• Also known as Forwarding Plane• Forwards traffic to the next hop along the path to the

selected destination network according to control plane logic

• Data plane packets go through the router• The routers/switches use what the control plane built

to dispose of incoming and outgoing frames and packets

Data Plane

• An SDN controller is the centralized repository of policy and control instructions for the network or application infrastructure.

• The controller bridges the gap between open, programmable network elements and the applications that communicate with them, automating the provisioning (the setup and management) of the entire infrastructure, including the network, services, and applications.

• The controller gives you a programmatic interface for setting policies andprovisioning services across your network.

SDN Controllers

• Virtualization: Use network resource without worrying about where it is physically located, how much it is, how it is organized, etc.

• Orchestration: Should be able to control and manage thousands of devices with one command.

• Programmable: Should be able to change behavior on the fly.

• Dynamic Scaling: Should be able to change size, quantity• Automation: To lower & minimize manual involvement

– Troubleshooting– Reduce downtime – Policy enforcement

Features

SDN Architecture

SDN Layers

SDN potential use Cases