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Software-Defined Networking

Simon Leinen Team Leader, Peta Solutions simon.leinen@switch.ch

eduPERT Performance U! 2013-03-07

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What is SDN!and why should I care?!

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Why SDN?!•  Networking software-defined anyway? •  Well yes, but… (is that of any use to us?) – Vertical integration dominates: Hardware, OS,

“applications” all in a (closed) box – Network-wide functions defined by protocols

Results: •  Resistance to innovation (“fossilization”) •  Cost/performance issues

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Drivers towards SDN!•  Researchers who want to “innovate” – Future Internet/”Clean Slate” initiatives

•  “Warehouse-scale computing” (Cloud) – Need to build scalable, cost-effective fabrics – Research shows it can be done (VL2,

Portland etc.) using fat trees/leaf+spine and multipath load balancing (e.g. Valiant) at edge

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Data Center Networks!

5 Source: “A simpler data center fabric emerges”, Lippis White Paper

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Data Center Networks!

6 Source: A simpler data center fabric emerges, Lippis White Paper

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Leaf-spine traffic flow (multipath)!

7 Source: Interop 2012 talk by Brad Hedlund�

Architecting Data Center Networks…

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“Mainframe business model”!

8 J. Hamilton, “Data Center Networks Are In My Way”, October 2010

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Possible Approaches!•  Separate forwarding/packet processing

logic (data plane) and control plane – OpenFlow (Kurt’s talk)

•  Improve onboard programmability – SDKs, better access to embedded OS

•  Use general-purpose hardware – E.g. Linux/Intel servers (Luke’s talk)

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Dumb Fabric/Smart Edge!Some SDN proponents suggest this architecture for future (DC) networks: •  Use a simple fabric for bottleneck-free bw. – Could be IP, MPLS, or OpenFlow net…

•  Implement functionality at edge – E.g. isolation, load distribution over multipath – E.g. in the CPU-based hypervisor

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NFV (Network Function Virtualization)!

•  Telco buzzword for something natural… •  “Network functions” can be run in VMs •  This is already happening: – Cisco Nexus 1000V – Cisco Cloud Services Router 1000V – Juniper vGW (Virtual Gateway) firewall

•  Note how “hardware-based” firewalls are superseded by Xeon-based ones

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Industry taking SDN seriously?!

•  2012-04-17: U. Hölzle gives talk @ONS about production Google OpenFlow WAN

•  2012-07-23: VMware acquires Nicira for USD 1.05 billion

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Do we have to take it seriously?!

•  If you’re an SDN researcher, yes J •  If you’re a backbone operator… not yet(?) •  If you have to do with campus networks

and edge network devices (firewalls etc.): yes

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What about Performance?!•  New approaches to fast networks:

massive multipath, stupid core, edge functions on CPUs

•  New requirements and new opportunities for instrumentation (measurements)

•  New opportunities for things to go wrong, e.g. OpenFlow table-update bottlenecks

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Further Reading!•  Gentle Introduction to SDN, S. Shenker, 2012�

http://www.youtube.com/watch?v=eXsCQdshMr4

•  Datacenter Networks Are In My Way, J. Hamilton, 2010 (read the slides!)http://perspectives.mvdirona.com/2010/10/31/DatacenterNetworksAreInMyWay.aspx

•  OpenFlow @Google, U. Hölzle, 2012 http://www.youtube.com/watch?v=VLHJUfgxEO4

•  The Future of Networking, and the Past of Protocols, S. Shenker, 2011�http://www.youtube.com/watch?v=YHeyuD89n1Y http://www.slideshare.net/martin_casado/sdn-abstractions

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Further Further Reading!•  Open Networking Summit (industry) – Each April in Silicon Valley

•  HotSDN workshop (research) – Each Summer wherever SIGCOMM is held

•  SDN MOOC by Nick Feamster (Georgia Tech.) – 6 weeks starting on 27 May�https://www.coursera.org/course/sdn?goback=.gde_4359316_member_207551682

•  Meta-list: http://www.nec-labs.com/~lume/sdn-reading-list.html

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