OpenFlow and Open Networking An Introduction and Overviewirg-intl.com/pdf/openflow_and_open_networking_ and Open Networking An Introduction and Overview Peter Christy, IRG, pchristy@irg-intl.com

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  • OpenFlow and Open Networking

    An Introduction and Overview Peter Christy, IRG, pchristy@irg-intl.com

    February 2012

    1 February 2012

  • What?: Modernizing the Control Plane

    This is all about modernizing the control plane of a network

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    2 February 2012

  • What?: Modernizing the Control Plane

    This is all about modernizing the control plane of a network o The data plane does the work of moving

    packets through the network

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    3 February 2012

  • What?: Modernizing the Control Plane

    This is all about modernizing the control plane of a network o The data plane does the work of moving

    packets through the network

    o The control plane is the means by which the data plane is configured, and how exceptions are handled

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    4 February 2012

  • The Data Plane A network consists of a set of

    interconnected switches.

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    5 February 2012

  • The Data Plane A network consists of a set of

    interconnected switches.

    Each switch is a server system with a purpose built operating system and application software, as well as specialized hardware in the form of line cards and packet forwarding hardware (PFH).

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    Server PFH

    Kernel

    O/S

    Applications

    6 February 2012

  • The Data Plane A network consists of a set of

    interconnected switches. Each switch is a server system

    with a purpose built operating system and application software, as well as specialized hardware in the form of line cards and packet forwarding hardware (PFH).

    The packet forwarding hardware operates by examining the various header bits on the packet, consulting a set of rules stored in high speed associative memory (CAM) and if an applicable rule is found, using the rule data to select the output link, assign a queuing priority, and possibility rewrite some of the header bits.

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    PFH

    CAM rules

    Server PFH

    Kernel

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    Applications

    7 February 2012

  • The Control Plane For most packets in a data center

    or SP network, the actions of the network are dictated by stored rules, executed by the PFH

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    PFH

    CAM rules

    8 February 2012

  • The Control Plane For most packets in a data center

    or SP network, the actions of the network are dictated by stored rules, executed by the PFH

    The control plane is the means by which the PFH rules are managed.

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    PFH

    CAM rules

    9 February 2012

  • The Control Plane For most packets in a data center

    or SP network, the actions of the network are dictated by stored rules, executed by the PFH

    The control plane is the means by which the PFH rules are managed.

    This can be done by command-line interactions with a network administrator (switch configuration) and then through the exchange of standardized control information with adjacent switches (e.g., routing protocols)

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    PFH

    CAM rules

    10 February 2012

  • History of OpenFlow OpenFlow began as an idea

    about how research networks could be built.

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    11 February 2012

  • History of OpenFlow OpenFlow began as an idea

    about how research networks could be built.

    Why not just build an experimental network? o Researchers cant generally afford to buy

    new devices and a build a new network.

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    12 February 2012

  • PFH

    Kernel

    O/S

    Applications

    History of OpenFlow OpenFlow began as an idea about

    how research networks could be built.

    Why not just build an experimental network? o Researchers cant generally afford to buy new

    devices and a build a new network.

    Why not add experimental software to existing switches? o Modern switches are all different because they

    each have proprietary and different software architecture internally, so writing additional code for them is difficult or impractical.

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    13 February 2012

  • History of OpenFlow OpenFlow began as an idea

    about how research networks could be built.

    Why not just build an experimental network? o Researchers cant generally afford to buy

    new devices and a build a new network.

    Why not add experimental software to existing switches? o Modern switches are all different because

    they each have proprietary and different software architecture internally, so writing additional code for them is difficult or impractical.

    What about programming the PFH? o In contrast to the software designs, PFH

    hardware is all similar. What about directly programming the Packet Forwarding Hardware?

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    PFH

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    14 February 2012

  • PFH

    Kernel

    O/S

    Applications

    OpenFlow: a PFH Control Protocol

    OpenFlow is a protocol by which the PFH hardware in a switch can be managed by software executing in a separate server, external to the switch, in a standardized way.

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    OpenFlow Controller

    Application Server

    15 February 2012

    The OpenFlow Protocol

  • Why Modernize? Paul Baran invented the Internet

    at Rand in the early 1960s.

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    16 February 2012

  • Why Modernize? Paul Baran invented the Internet

    at Rand in the early 1960s.

    WWII and the ensuing Cold War demonstrated

    1. the necessity of reliable communications for defense or in a war and

    2. the lethal destruction possible with missiles, long-range bombers, and nuclear weapons.

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    17 February 2012

  • Why Modernize? Paul Baran invented the

    Internet at Rand in the early 1960s.

    WWII and the ensuing Cold War demonstrated

    1. the necessity of reliable communications for defense or in a war and

    2. the lethal destruction possible with missiles, long-range bombers, and nuclear weapons.

    The phone system in the US at the time was a centralized circuit-switching system that would be very easy to disrupt or destroy.

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    18 February 2012

  • Why Modernize? Paul Baran invented the

    Internet at Rand in the early 1960s.

    WWII and the ensuing Cold War demonstrated

    1. the necessity of reliable communications for defense or in a war and

    2. the lethal destruction possible with missiles, long-range bombers, and nuclear weapons.

    The phone system in the US at the time was a centralized circuit-switching system that would be very easy to disrupt or destroy.

    CO

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    C5 CO

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    19 February 2012

  • Barans Clever Solution Packetized Voice

    Communications o Transform voice communications

    connections into sequences of packets of voice data.

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    20 February 2012

  • Barans Clever Solution Packetized Voice

    Communications o Transform voice communications

    connections into sequences of packets of voice data.

    o Transmit each packet independently.

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    21 February 2012

  • Barans Clever Solution Packetized Voice

    Communications o Transform voice communications

    connections into sequences of packets of voice data.

    o Transmit each packet independently.

    o Have the packet forwarding devices