Thursday, 9 January 2014

SDN & OpenFlow 101

Why SDN and Virtual Networking?

What is Network Virtualization?

·         Representation of one or more logical network topologies on the same infrastructure.

·         Many different instantiations

o   Virtual LANs (VLANs)

o    Various technologies and network test-beds

o   Today: VMWare, Nicira, Cisco etc.

Applications of Virtual Networking

·         Experimentation on production networks

o   Can run (virtual) experimental infrastructure in parallel with production

·         Rapid deployment and development

o   Can deploy services independently from underlying vendor hardware

·         Dynamic scaling of resources

o   Can allocate from “pool” of resources


Benefits of Network Virtualization

·         Sharing

o   Multiple logical routers on a single platform

o   Resource isolation in CPU, memory, bandwidth, forwarding tables, … 

·         Customizability

o   Customizable routing and forwarding software

o   General-purpose CPUs for the control plane

o   Network processors and FPGAs for data plane


Control and Data Planes:

·         Control Plane: Logic for controlling forwarding behavior.

o   Examples: routing protocols, network middlebox configuration.ž

·         Data Plane: Forward traffic according to control plane logic

o   Examples: IP forwarding, Layer 2 switching


Why are Separate Control and Data Planes desirable?

·         Independent evolution and development

o   The software control of the network can evolve independently of the hardware.

·         Control from high-level software program

o   Control behavior using higher-order programs

o   Debug/check behavior more easily

Separation of Control and Data planes helps in:

·         Data centers: VM migration, Layer 2 routing

·         Routing: More control over decision logic

·         Enterprise networks: Security applications

·         Research networks: Coexistence with production


Separating Control allows advances in:

·         More rapid innovation: Control logic is not tied to hardware

·         Network-wide view: Easier to infer (and reason about) network behavior

·         More flexibility: Can introduce new services more easily


Network Virtualization Is The Largest Transformation IT in 30 Years


Where will SDN be deployed?

1.       Multi-tenant “virtualized” data centers

      Public and private clouds

2.       WANs

      Google WAN

      Eventually, public WANs

3.       Enterprise networks

      Greater control, fewer middleboxes

4.       Home networks

      Outsourced management

5.       Cellular Networks

      Separation of service from physical infrastructure

6.       Research and Education Networks

      National backbones

      College campus networks



·         It's a protocol for control the forwarding behavior of Ethernet switches in a Software Defined Network

·         Initially released by the Clean Slate Program at Stanford, its specification is now maintained by the Open Networking Forum

·         OpenFlow is similar to an x86 instruction set for the network

·         Provide open interface to “black box” networking node

§  (ie. Routers, L2/L3 switch) to enable visibility and openness in network

§  Separation of control plane and data plane.

§  The datapath of an OpenFlow Switch consists of a Flow Table, and an action associated with each flow entry

§  The control path consists of a controller which programs the flow entry in the flow table

§  OpenFlow is based on an Ethernet switch, with an internal flow-table, and a standardized interface to add and remove flow entries


OpenFlow Basics I




OpenFlow Basics II


OpenFlow Consortium:


§  Evangelize OpenFlow to vendors

§  Whitepaper, OpenFlow Switch Specification, Reference Designs

§  Licensing: Free for research and commercial use


OpenFlow building blocks


Components of OpenFlow Network:


OpenFlow Controllers


·         Secure Channel (SC)

o   SC is the interface that connects each OpenFlow switch to controller

o   A controller configures and manages the switch via this interface.

§  Receives events from the switch

§  Send packets out the switch

§  SC establishes and terminates the connection between OpneFlow Switch and the controller using the procedures

§  Connection Setup

§  Connection Interrupt

§  The SC connection is a TLS  connection.  Switch and controller mutually authenticate by exchanging certificates signed by a site-specific private key.

Dynamic Flow Aggregation on an OpenFlow Network


§  Different Networks want different flow granularity (ISP, Backbone,…)

§  Switch resources are limited (flow entries, memory)

§  Network management is hard

§  Current Solutions : MPLS, IP aggregation

      How does OpenFlow Help?

§  Dynamically define flow granularity by wildcarding arbitrary header fields

§  Granularity is on the switch flow entries, no packet rewrite or encapsulation

§  Create meaningful bundles and manage them using your own software (reroute, monitor)


Virtualizing OpenFlow

      Network operators “Delegate” control of subsets of network hardware and/or traffic to other network operators or users

      Multiple controllers can talk to the same set of switches

      Imagine a hypervisor for network equipments

      Allow experiments to be run on the network in isolation of each other and production traffic

The “Software-defined Network”





·         More innovation in network services

§  Owners, operators, 3rd party developers, researchers can improve the network

§  E.g. energy management, data center management, policy routing, access control, denial of service, mobility

§  Lower barrier to entry for competition

§  Healthier market place, new players


Next: Open vSwitch…


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Breakfast At Serengeti

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The Ngorongoro Family

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Tabloid Time: The Aliens Are a'Landing ?!.. ;-)

At the risk of being ridiculed and being labelled a freak, I shall like to draw everyone's attention to the following recent events....If you watch the videos then turn on the sound for the commentary...

Fireball across Ausin, Texas (16th Feb 2009). According to BBC, apparently, its NOT debris from a recent satellite collision...:

Same in Idaho in recent times. NO meteor remains found yet:

Exactly same in Sweden:

This was recorded on 25th Feb 2007 in Dakota, US:

This year has seen three of the spookiest UFO videos surface, with people in India, Mexico and even in space, NASA, spotting things they couldn't explain:

CHECK out this one on 24th Januray, 2009 in Argentina close to Buenos Aires:
You tube:
Press Coverage

AND Lastly, and more importantly, from Buzz Aldrin on Apollo 11 :

Heh?! Don't know how authentic these news are... don't even know if these are UFO's or meteors or ball lightning or something else. But, if meteors, then where are the meteorites ? However, I see no reason why life cannot exist in other planets and why they could not be sneaking around here :-) . I for one, have long suspected some of my relations to be space aliens or at least X-people from X-files :-)

I am waiting for a job on an Alien spaceship myself. :-)

Giraffes in Parallel Universe

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Serengeti Shall Never Die

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Wildebeeste Calf starts running only 5 min. after being born. CLICK on the pitcture to view Slideshow