Demystifying SDN Saurav Das AT&T Talk 3/27/14 1

2 A number of slides are courtesy of

Outline What is SDN? (or how was it originally intended) Different Shades of SDN SDN Myths and Misconceptions

© 2013 SDN Academy, LLC™. All Rights Reserved.4 (A) Forwarding Abstraction: Match-Action Tables (B) State-Distribution Abstraction: Global View Network OS running on distributed controllers Configuration; Control over Forwarding; Monitoring What is SDN?

© 2013 SDN Academy, LLC™. All Rights Reserved.5 What is an Abstraction? Data – plane abstractions Where are the control-plane abstractions?

© 2013 SDN Academy, LLC™. All Rights Reserved. Where are the Control-Plane Abstractions? 6 Networking is about getting stuff from here to there … Is OSPF a topology abstraction? Is OSPF a routing abstraction? Can I use it to route IPv6 traffic? well you need v2 for IPv4 and v3 for IPv6 Can I use it to route multicast traffic? no you need MOSPF or PIM Can I use it in Ethernet networks? no you need TRILL (with IS-IS) for that IGP- Route Advert, Link- State OSPF v2 TE Label Distrib ution RSVP- TE VPN- IPv4 Route Advert MP- BGP E-BGP learned Route Advert I-BGP + RR PE Label Distrib ution LDP Developing a Control Plane Abstraction Requires Developing a Data Plane (Forwarding) Abstraction Developing a Control Plane Abstraction Requires Developing a Data Plane (Forwarding) Abstraction

Towards a Forwarding Abstraction 7

(A) Forwarding Abstraction 8 A way to define forwarding behavior that is not layer or vendor specific

Interfaces are the Realizations of Abstractions 9

10 (B) State Distribution Abstraction Abstracted away by Network Operating System State Collection Dissemination & Synchronization Application Isolation Proposed abstraction: global network view Control program should not have to handle distributed- state details

App Switch App Switch Controller northbound interface So What is SDN? southbound Interface eg. OpenFlow 11 Forwarding Abstraction: Match-Action Tables Control Abstraction: Global View Interfaces are the Realizations of Abstractions

© 2013 SDN Academy, LLC™. All Rights Reserved.12 What is SDN? – A Simpler View SDN has two defining characteristics. First, it physically separates the control plane (which decides how to handle the traffic) from the data plane (which forwards traffic according to decisions that the control plane makes). Second, SDN consolidates the control plane, so that a single instance controls multiple data- plane elements -- The Road To SDN,

© 2013 SDN Academy, LLC™. All Rights Reserved.13 Benefits of SDN 1.Simpler Control with Greater Flexibility Networks work because we can master complexity, but what we should be doing is extracting simplicity, with the right abstractions 2.Programmability: Speed of Innovation, Ease of Service Insertion & Faster Time to Market Does not involve changing/creating a fully distributed protocol 3.Lower Total Cost of Ownership (TCO) Lower Opex – easier to manage, troubleshoot, emulate, automate, optimize Lower Capex – replacing proprietary hardware, pay for what you need and no more.

© 2013 SDN Academy, LLC™. All Rights Reserved.14 [1] ‘Pure’ SDN / ‘True’ SDN? 14 (A) Forwarding Abstraction: Match-Action Tables (B) State-Distribution Abstraction: Global View Network OS running on distributed controllers Configuration; Control over Forwarding; Monitoring Separation D C Simplicity Programmability Lower Capex Lower Opex

© 2013 SDN Academy, LLC™. All Rights Reserved. Different Shades of SDN 15 ‘Pure’ SDN or ‘True’ SDN Orchestration/ Automation/ Gluework Traditional Networking + SDN ‘Hook’ Overlay Networks for DC Network Virtualization Traditional Networking + White-Box Traditional Networking + White-Box + Orchestration Decoupled Traditional Networking Decoupled Traditional Networking + Global View Open Source Networking

© 2013 SDN Academy, LLC™. All Rights Reserved.16 [2] Orchestration/Automation/Gluework Separation D C Simplicity Programmability Lower Capex Lower Opex “Controller” Vendor X Vendor X Vendor Y Vendor Y Vendor Z Vendor Z CLI EMS Provides Automation By Orchestrating Across Automation Programmability Modified NMS, OpenStack, cli-scripts  automate Configuration & provisioning Changing Behavior (if-then-else)

© 2013 SDN Academy, LLC™. All Rights Reserved.17 [3] Traditional Networking + ‘SDN Hook’ Legacy Preserving with Claimed Advantages  A.Customer realizes benefits of SDN on same infrastructure B.Allows vendor to build SDN on existing products CLI Replacement ‘Controller’ Instead of CLI expect scripts, write python programs L2 L3 Tunnel ECMP ACL PBR overide Under traditional networking control

© 2013 SDN Academy, LLC™. All Rights Reserved.18 [3] Traditional Networking + ‘SDN Hook’ Legacy Preserving with Claimed Advantages  A.Customer realizes benefits of SDN on same infrastructure B.Allows vendor to build SDN on existing products Point Solutions PCE Exampe: PCE based PCEP BGP-LS RSVP, LDP OSPF v2, OSPF v3, ISIS MP-BGP I-BGP + RR MOSPF, PIM

© 2013 SDN Academy, LLC™. All Rights Reserved.19 [3] Traditional Networking + ‘SDN Hook’ Legacy Preserving with Claimed Advantages  A.Customer realizes benefits of SDN on same infrastructure B.Allows vendor to build SDN on existing products ‘Controller’ Hybrid Solutions / ‘Ships-in-the- night’ Some VLANs have SDN control

© 2013 SDN Academy, LLC™. All Rights Reserved.20 [3] Traditional Networking + ‘SDN Hook’ Separation D C Simplicity Programmability Lower Capex Lower Opex Legacy Preserving with Claimed Advantages  A.Customer realizes benefits of SDN on same infrastructure B.Allows vendor to build SDN on existing products CLI Replacement ‘Controller’ Instead of CLI expect scripts, write python programs Point Solutions ‘Controller’ Eg. PCE based Hybrid Solutions / ‘Ships-in-the- night’ ‘Controller’ Some VLANs have SDN control

© 2013 SDN Academy, LLC™. All Rights Reserved.21 [4] Overlay Networking ‘Controller’ Separation D C Simplicity Programmability Lower Capex Lower Opex Underlying L2/L3 fabric R1 R2R3 B1 B2 B3 Orchestrator OpenStack, CloudStack, VMWare vSwitch, vRouter R1 R2 R3 B3 B1 B2 Context: Data center network virtualization for public/private cloud; presented from the viewpoint of the cloud provider (not the tenant)!

© 2013 SDN Academy, LLC™. All Rights Reserved.22 [5] Traditional Networking + White Box Data Path (Hardware) Data Path (Hardware) Control Plane (Software) Separation D C Simplicity Programmability Lower Capex Lower Opex Merchant Silicon White -box

© 2013 SDN Academy, LLC™. All Rights Reserved.23 [5.5] Traditional Networking + White Box + Orchestration Data Path (Hardware) Data Path (Hardware) Control Plane (Software) Separation D C Simplicity Programmability Lower Capex Lower Opex Merchant Silicon White -box

© 2013 SDN Academy, LLC™. All Rights Reserved.24 [6] Decoupled Traditional Networking Separation D C Simplicity Programmability Lower Capex Lower Opex Traditional networking control plane Usually proprietary, could be OF, See IETF ForCES 1. Software stacks 2. Merchant Silicon

© 2013 SDN Academy, LLC™. All Rights Reserved.25 [6.5] Decoupled Traditional Networking + Global View Separation D C Simplicity Programmability Lower Capex Lower Opex Traditional networking control plane Usually proprietary, could be OF, See IETF ForCES 1. Software stacks 2. Merchant Silicon ‘Controller’

© 2013 SDN Academy, LLC™. All Rights Reserved.26 [7] Open Source Networking Separation D C Simplicity Programmability Lower Capex Lower Opex Has Open Source ever worked in networking? What are the best know open source networking projects… Quagga OVS … not used in production without modification What about controllers?: No open source controller used in production No open source networking project today is complete solution Open source is part of the solution

© 2013 SDN Academy, LLC™. All Rights Reserved.27 Separate D C Simplicity Programm- ability Lower Capex Lower Opex True SDN Orchestration /Automation Traditional netw. + SDN ‘Hook’ Traditional netw. + White Box Overlay Networks for DC net virt. Decoupled Traditional Netw. Decoupled Trad. n/w + Global View Open Source Different Shades of SDN Traditional netw. + White Box + Orch.

© 2013 SDN Academy, LLC™. All Rights Reserved.28 Myths & Misconceptions SDN is Network Virtualization SDN == NFV SDN is about centralized control OpenFlow is not mature

© 2013 SDN Academy, LLC™. All Rights Reserved. statebehaviorInterface msg match Eth, VLAN, IP, L4 flows 1.0 Q4 ‘09 single message queue w/optional barriers ports forward {0, 1, n} 1.1 Q1 ‘11 + Multiple Tables/Pipelines: + Group Tables + forward 1-in-n (ECMP) + match QinQ, MPLS, SCTP + match virtual ports + extensible match + extensible actions 1.2 Q4 ‘11 + IPv6 + multiple controllers 1.3 Q2 ‘12 + per-flow metering + tunnel-id OpenFlow has evolved towards production readiness. + multiple channels (auxiliary connections) 1.4 Q4 ‘13 + optical ports + synchronized tables + bundle messages

© 2013 SDN Academy, LLC™. All Rights Reserved.30 Myths & Misconceptions SDN is Network Virtualization SDN == NFV SDN is about centralized control OpenFlow is not mature OpenFlow does not work with current hardware OpenFlow does not scale Do we really need another protocol? I can’t just throw away my existing network …

Source: Ed Crabbe, Google 31

Source: Ed Crabbe, Google 32

33 Source: Guru Parulkar

34 Source: Guru Parulkar

Q & A