Software Defined Networking: tecnologia e prospettive Prof. Stefano Salsano stefano.salsano@uniroma2.it Seminario nel corso “Advanced Networking and Internet Modeling„ Prof. Francesco Lo Presti 26 Maggio 2015

Outline SDN motivations: Internet ossification, network complexity, barriers to innovation SDN approach, goals and dreams… A bit of technology: OpenFlow Application examples SDN and cloud Google’s SDN WAN SDN and Network Function Virtualization

Internet success The Internet success is a remarkable story, from a research infrastructure to a global network, interconnecting billions of devices and people Innovation looks easy on the Internet as we witness always new and more powerful services and applications Web, P2P, VoIP, social networks, video streaming…

Network ossification The history is a bit different behind the scene: Huge complexity Few people can innovate Closed equipment Network «ossification» 4 4

Classical network architecture Distributed control plane Distributed routing protocols: OSPF, IS-IS, BGP, etc. Feature Operating System Feature Specialized Packet Forwarding Hardware Operating System Feature Specialized Packet Forwarding Hardware Operating System Classical computer network architecture Feature Specialized Packet Forwarding Hardware Operating System Specialized Packet Forwarding Hardware Feature Operating System Specialized Packet Forwarding Hardware

The Networking Industry (2010s) Routing, management, mobility management, access control, VPNs, … Feature Feature Million of lines of source code 5400 RFCs Barrier to entry Operating System Specialized Packet Forwarding Hardware Billions of gates Complex Power Hungry The networking industry is broken. Why doesn’t it look like the server market? Historical accident. Overwhelming complexity. The history of OpenFlow starts with a realization that the state of the industry is broken. Analogy: like the computer industry in the late 70’s and early 80’s before IBM compatibles and Windows: vertically integrated. Closed, vertically integrated, boated, complex, proprietary Many complex functions baked into the infrastructure OSPF, BGP, multicast, differentiated services, Traffic Engineering, NAT, firewalls, MPLS, redundant layers, … Little ability for non-telco network operators to get what they want Functionality defined by standards, put in hardware, deployed on nodes 6 6

Outline SDN motivations: Internet ossification, network complexity, barriers to innovation SDN approach, goals and dreams… A bit of technology: OpenFlow Application examples SDN and cloud Google’s SDN WAN SDN and Network Function Virtualization

Software Defined Network Well-defined open API Constructs a logical map of the network Feature Feature Northbound Network OS Open, vendor-agnostic protocol Southbound OpenFlow Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware 17/09/2013

Analogy with IT industry: from mainframes to PCs App Specialized Applications Linux Mac OS Windows (OS) or Specialized Operating System Specialized Hardware Microprocessor The mainframe industry in the 1980s was vertical and closed: it consisted of specialized hardware, operating system and applications --- all from the same company. A revolution happened when open interfaces started to appear. The industry became horizontal. Innovation exploded. Mainframe industry in the 1980s: Vertically integrated Closed, proprietary Slow innovation Small industry Horizontal Open interfaces Rapid innovation Huge industry

Analogy with IT industry: from closed box to SDN Specialized Features App Specialized Control Plane Control Plane Control Plane Control Plane or or Specialized Hardware Merchant Switching Chips Networking industry in 2010s: Vertically integrated Closed, proprietary Slow innovation Horizontal Open interfaces Rapid innovation

SDN Concept Separate Control plane and Data plane entities Network intelligence and state are logically centralized The underlying network infrastructure is abstracted from the applications Execute or run Control plane software on general purpose hardware Decouple from specific networking hardware Use commodity servers Have programmable data planes Maintain, control and program data plane state from a central entity An architecture to control not just a networking device but an entire network

Network OS and OpenFlow Distributed system that creates a consistent, up-to-date network view, runs on servers (controllers) in the network Uses an open protocol to: Get state information from forwarding elements Give control directives to forwarding elements OpenFlow is a protocol for remotely controlling the forwarding table of a switch or router is one element of SDN

Abstractions in the Control Plane Network Virtualization Well-defined API Routing Traffic Engineering Other Applications Network Map Abstraction Network Operating System or “Controller” Forwarding Separation of Data and Control Plane Forwarding Forwarding Forwarding

Forwarding Abstractions Purpose: Abstract away forwarding hardware Flexible Behavior specified by control plane Built from basic set of forwarding primitives Minimal Streamlined for speed and low-power Control program not vendor-specific OpenFlow is an example of such an abstraction

SDN promises (or dreams…) Innovation beyond IP, clean slate approaches… Change of paradigm «Redefining Abstractions» (see Scott Shenker presentation) Openness open fast switching hardware, open controllers

Outline SDN motivations: Internet ossification, network complexity, barriers to innovation SDN approach, goals and dreams… A bit of technology: OpenFlow Application examples SDN and cloud Google’s SDN WAN SDN and Network Function Virtualization

Traditional network node: Switch Typical Networking Software Management plane Control Plane – The brain/decision maker Data Plane – Packet forwarder

Traditional network node: Router Router can be partitioned into control and data plane Management plane/ configuration Control plane / Decision: OSPF (Open Shortest Path First) Data plane / Forwarding Adjacent Router Router Management/Policy plane Configuration / CLI / GUI Static routes Control plane OSPF Neighbor table Link state database IP routing table Forwarding table Data plane Routing Switching

OpenFlow Controller Control Path OpenFlow Data Path (Hardware) OpenFlow Basics OpenFlow Controller OpenFlow Protocol (SSL/TCP) Control Path OpenFlow Data Path (Hardware)

OpenFlow Basics Network OS Ethernet Switch Control Program A Control Program B Network OS OpenFlow Protocol Ethernet Switch Control Path OpenFlow Data Path (Hardware)

OpenFlow Basics Network OS Control Program A Control Program B “If header = p, send to port 4” “If header = q, overwrite header with r, add header s, and send to ports 5,6” Packet Forwarding “If header = ?, send to me” Flow Table(s) Packet Forwarding Packet Forwarding

OpenFlow Primitives <Match, Action> Match arbitrary bits in headers: Match on any header, or new header Allows any flow granularity Action Forward to port(s), drop, send to controller Overwrite header with mask, push or pop Forward at specific bit-rate <Match, Action> Header Data Match: 1000x01xx0101001x

General Forwarding Abstraction Small set of primitives “Forwarding instruction set” Protocol independent Backward compatible Switches, routers, WiFi APs, basestations, TDM/WDM

OpenFlow example OpenFlow Client Controller PC Software Layer MAC src Flow Table MAC src dst IP Src Dst TCP sport dport Action Hardware Layer * 5.6.7.8 port 1 port 1 port 2 port 3 port 4 5.6.7.8 1.2.3.4

OpenFlow Basics Flow Table Entries Rule Action Stats Packet + byte counters Forward packet to zero or more ports Encapsulate and forward to controller Send to normal processing pipeline Modify Fields Any extensions you add! Now I’ll describe the API that tries to meet these goals. Switch Port VLAN ID VLAN pcp MAC src MAC dst Eth type IP Src IP Dst IP ToS IP Prot L4 sport L4 dport + mask what fields to match

Examples Switching Flow Switching Firewall Switch Port MAC src dst Eth type VLAN ID IP Src Dst Prot TCP sport dport Action * * 00:1f:.. * * * * * * * port6 Flow Switching Switch Port MAC src dst Eth type VLAN ID IP Src Dst Prot TCP sport dport Action port3 00:20.. 00:1f.. 0800 vlan1 1.2.3.4 5.6.7.8 4 17264 80 port6 Firewall Switch Port MAC src dst Eth type VLAN ID IP Src Dst Prot TCP sport dport Action * * * * * * * * * 22 drop

Reactive vs. Proactive (pre-populated) First packet of flow triggers controller to insert flow entries Efficient use of flow table Every flow incurs small additional flow setup time If control connection lost, switch has limited utility Extremely simple fault recovery Proactive Controller pre-populates flow table in switch Zero additional flow setup time Loss of control connection does not disrupt traffic Essentially requires aggregated (wildcard) rules Simple fault recovery but not necessarily simple or optimal

Microflow vs. Aggregated Every flow is individually set up by controller Exact-match flow entries Flow table contains one entry per flow Good for fine grain control, policy, and monitoring, e.g. campus Aggregated One flow entry covers large groups of flows Wildcard flow entries Flow table contains one entry per category of flows Good for large number of flows, e.g. backbone

Virtualization or “Slicing” Virtualization trend Controller 1 App Controller 2 Virtualization or “Slicing” OpenFlow NOX (Network OS) Network OS App App App Windows (OS) Linux Mac OS Windows (OS) Linux Mac OS Windows (OS) Linux Mac OS Virtualization layer x86 (Computer) Computer Industry Network Industry

Virtualization or “Slicing” Layer Isolated “slices” Many operating systems, or Many versions App Network Operating System 1 Network Operating System 2 Network Operating System 3 Network Operating System 4 Open interface to hardware Virtualization or “Slicing” Layer Open interface to hardware Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware Simple Packet Forwarding Hardware 17/09/2013 30

Outline SDN motivations: Internet ossification, network complexity, barriers to innovation SDN approach, goals and dreams… A bit of technology: OpenFlow Application examples SDN and cloud Google’s SDN WAN SDN and Network Function Virtualization

SDN and cloud Cloud x 10000… “multi-tenant” multi site

SDN and cloud Cloud computing service providers face the issue of multi-tenancy at the network level IP and Ethernet each have virtual network capability, but limited in terms of how many tenants can be supported how isolated each tenant configuration and management complexity SDN is increasingly accepted as the path to "cloud networking"

Neutron service in the OpenStack cloud architecture (was Quantum) Nova Compute Service Virtual Machines Swift Storage Object Store Basic Network Connectivity Nova, Swift, and Neutrum API Servers Disks Neutrum Service Virtual Networks Networks Developers have ability to create multiple networks for their own purposes (multi-tier apps) May support provisioning of both virtual and physical networks – differences captured through plugin’s

Neutrum service in the OpenStack cloud architecture User Application – CLI - Horizon Dashboard - Tools Tenant API Tenant API Network Service (Neutrum) Compute Service (Nova) System Admin Internal API Admin API Plug-In Compute Node Hypervisor vSwitch Physical Network Router/Switch Clustered Network Controller

Available Neutrum plug-ins Open vSwitch Linux bridge Nicira NVP Cisco (Nexus switches and UCS VM-FEX) WIP: VXLAN NTT Labs Ryu OpenFlow controller NEC OpenFlow Big Switch Floodlight Most of them are SDN based !

The zoo of network technologies

Data center simplification Traditional Network Fabric

Network Fabric Defined Flat network Every port virtually connected to every other High speed network; 10 Gig-E, roadmap to 40 Gig-E and 100 Gig-E Operationally simple Optimized for virtual traffic and east west traffic flows Optimized packet processing

The shift toward SDNs Allows for the network to be in better alignment with the current data center trends Brings a high level of agility to the network Enables programmability Improves application performance Abstracts the control layer from the network infrastructure lay Complements fabrics Creates scalable network virtualization

Outline SDN motivations: Internet ossification, network complexity, barriers to innovation SDN approach, goals and dreams… A bit of technology: OpenFlow Application examples SDN and cloud Google’s SDN WAN SDN and Network Function Virtualization

Google’s B4: an SDN success story In April 2012 Google presented their OpenFlow based WAN (“B4”), globally interconnecting the Data Centers B4 is based on a SDN architecture using OpenFlow to control relatively simple switches built from merchant silicon Google engineered the switches and the SDN architecture

B4 worldwide deployment (2011)

Typical WAN engineering rules WAN links are typically provisioned to 30-40% average utilization. This can mask virtually all link or router failures from clients. Such overprovisioning give reliability at the costs of 2-3x bandwidth over-provisioning and high-end routing gear.

Google’s Requirements Google fully controls applications and server using the WAN The most bandwidth intensive applications are large-scale data copies: they can adapt to available capacity The number of data center is limited, making centralized bandwidth control feasible

Traffic Engineering Using SDN, B4 simultaneously supports standard routing protocols and centralized TE TE algorithms allow to: adjudicate among competing demands during resource constraint use multipath forwarding/tunneling dynamically reallocate bandwidth in the face of link/switch failures Many B4 links to run at near 100% utilization and all links to average 70% utilization

The SDN switches

SDN based WAN architecture

Performance measurements link utilization ratio high prio / low prio low prio loss high prio loss

…and if you are not Google ? A truly open SDN eco-system will grow, including controllers/network OS, management tools, switching equipment, and “network applications” (e.g. a TE component) Vendors will include SDN concepts in their solutions, mostly in a proprietary way ?

«SDN washing» All main networking equipment vendors are now offering their SDN products and solutions “SDN washing” – when networking vendors essentially take their existing technologies and try to re-label them as SDN products

OpenDayLight Cisco, Juniper, Ericsson, IBM, NEC and other network vendors are joining up to standardize SDN (April 2013) with OpenDayLight project

OpenDayLight

Outline SDN motivations: Internet ossification, network complexity, barriers to innovation SDN approach, goals and dreams… A bit of technology: OpenFlow Application examples SDN and cloud Google’s SDN WAN SDN and Network Function Virtualization

SDN and NFV (Network Function Virtualization) NVF: a Network-operator-driven specification group within ETSI. Initiated by 13 carriers now grown to 23 members http://portal.etsi.org/portal/server.pt/community/NFV/367

SDN and NFV (Network Function Virtualization) Independent Software Vendors BRAS Firewall DPI CDN Tester/QoE monitor WAN Acceleration Message Router Radio Network Controller Carrier Grade NAT Session Border Classical Network Appliance Approach PE Router SGSN/GGSN Generic High Volume Ethernet Switches Generic High Volume Servers Generic High Volume Storage Orchestrated, automatic remote install Network Functions Virtualisation Approach hypervisors The Classical network appliance approach uses a proprietary chassis for every new service, some typical examples are shown above left. Although inside the appliances use similar chips they are packaged very differently outside. This creates complexity through the entire life cycle of network services e.g. Design, procurement, test, deployment, configuration, repair, maintenance, replacement, end-of-life, removal. There is no economies of scale (some boxes may only sell in the thousands as opposed to 9 Million IT servers every year). The need for start-ups to develop new hardware, including getting it NEBs and ETSI qualified, is a significant cost and deterrent to enter the telecoms market. The Network Virtualisation (NV) approach replaces physical network appliances with software virtual appliances running on commodity IT servers. Using open IT techniques allows a competitive and innovative ecosystem to exploit the many x86 and Linux programmers in the world. The Virtual Appliances can be installed on IT servers using orchestration software, this will automatically and remotely install software, driven either by traffic demands or customer orders. To complement the standard high volume IT servers we will also use standard high volume storage and Ethernet switches. The standard high volume Ethernet switches will use merchant silicon which spreads the cost of switching ASICs over the widest possible Enterprise & Carrier market. 56

NFV and SDN are complementary Open Innovation Network Functions Virtualisation Software Defined Networks Creates operational flexibility Reduces Reduces CapEx, OpEx, space & power delivery time consumption Creates control abstractions to foster innovation. Creates competitive supply of innovative applications by third parties

Outline SDN motivations: Internet ossification, network complexity, barriers to innovation SDN approach, goals and dreams… A bit of technology: OpenFlow Application examples SDN and cloud Google’s SDN WAN SDN and Network Function Virtualization Final remarks 17/09/2013

The two paths to SDN (r)evolution New Abstractions / high level modeling of networks Disruptive low cost net architectures and open hardware Open Source Software (for Carriers’ Class nodes) Open Innovation Revolutionary path : disruptive innovation Evolutionary path : progressive innovation Seamless integration in current networks, compatibility with legacy Solutions from traditional Vendors (or even Start-ups) … Costs Reductions (CAPEX, OPEX)

Questions ? Thank you for your attention ! Stefano Salsano, Ph. D. Associate Professor e-mail: stefano.salsano@uniroma2.it http://netgroup.uniroma2.it/Stefano_Salsano/ Phone: +39 06 7259 7770 Fax: +39 06 7259 7435 UNIVERSITY OF ROME “TOR VERGATA” Department of Electronics Engineering Via del Politecnico, 1 - 00133 Rome - Italy

Suggested Readings A. Manzalini, V. Vercellone, M. Ullio, «Software Defined Networking: sfide ed opportunità per le reti del futuro», Notiziario Tecnico Telecom Italia, n.1/2003 http://www.telecomitalia.com/content/dam/telecomitalia/it/archivio/documenti/Innovazione/NotiziarioTecnico/2013/n1-2013/NT1-4-2013.pdf N. McKeown et al. «OpenFlow: Enabling Innovation in Campus Networks», CCR 2008 http://www.openflow.org/documents/openflow-wp-latest.pdf

Main sources Jennifer Rexford “Enabling Innovation Inside the Network” Scott Shenker with Martín Casado, Teemu Koponen, Nick McKeown and others “The Future of Networking, and the Past of Protocols” Rob Sherwood (with help from many others) “An Experimenter’s Guide to OpenFlow” - GENI Engineering Workshop June 2010 Brandon Heller, Rob Sherwood, David Erickson, Hideyuki Shimonishi, Srini Seetharaman, Murphy McCauley, “Tutorial 1: SDN for Engineers” Dan Pitt, “The Open Networking Foundation: OpenFlow & SDN from lab to market” Yeh-Ching Chung, “Network Virtualization - Software Defined Network”

Main sources Tom Nolle “The role of software-defined networks in cloud computing” Lew Tucker, “Quantum: What it is and Where it’s going” Zeus Kerravala, “The Time for ICT is Now” Tom Nollle “Understanding the relationship between SDN and NFV” Bob Briscoe (+ Don Clarke, Pete Willis, Andy Reid, Paul Veitch), “Network Functions Virtualisation” Antonio Manzalini, “Software Will Eat the Networks – Welcome to the Blue SDN”

My work on SDN OSHI Open Source Hybrid IP/SDN networking http://netgroup.uniroma2.it/OSHI/ The DREAMER project http://netgroup.uniroma2.it/DREAMER/ S. Salsano, P. L. Ventre, F. Lombardo, G. Siracusano, M. Gerola, E. Salvadori, M. Santuari, M. Campanella, L. Prete “OSHI - Open Source Hybrid IP/SDN networking and Mantoo - a set of management tools for controlling SDN/NFV experiments”, submitted paper (May 2015) S. Salsano, P. L. Ventre, L. Prete, G. Siracusano, M. Gerola, E. Salvadori, “Open Source Hybrid IP/SDN networking (and its emulation on Mininet and on distributed SDN testbeds)”, 3rd European Workshop on Software Defined Networks, EWSDN 2014, 1-3 September 2014, Budapest, Hungary M. Gerola, M. Santuari, E. Salvadori, S. Salsano, P. L. Ventre, M. Campanella, F. Lombardo, G. Siracusano, “ICONA: Inter Cluster ONOS Network Application”, demo paper, 1st IEEE Conference on Network Softwarization (Netsoft 2015), London, UK, 13-17 April 2015 N. Blefari-Melazzi, A. Detti, G. Morabito, S. Salsano, L. Veltri, “Information Centric Networking over SDN and OpenFlow: Architectural Aspects and Experiments on the OFELIA Testbed”, to appear in Elsevier Computer Networks, Special Issue on Information-Centric Networking (ICN), 2013 N. Blefari-Melazzi, A. Detti, G. Mazza, G. Morabito, S. Salsano, L. Veltri, “An OpenFlow-based Testbed for Information Centric Networking”, Future Network & Mobile Summit 2012, 4-6 July 2012, Berlin, Germany L. Veltri, G. Morabito, S. Salsano, N. Blefari-Melazzi, A. Detti, “Supporting Information-Centric Functionality in Software Defined Networks”, SDN’12: Workshop on Software Defined Networks, Co-located with the IEEE International Conference on Communications (ICC), June 10-15 2012, Ottawa, Canada A. Detti , C. Pisa, S. Salsano, N. Blefari-Melazzi, “Wireless Mesh Software Defined Networks (wmSDN)”, The 2nd International Workshop on Community Networks and Bottom-up-Broadband (CNBuB 2013), Lyon, France, October 7th, 2013 17/09/2013