Introduction to SDN (Software Defined Networking)

Associate Prof Dr Chaodit Aswakul Network Research Group

Department of Electrical Engineering Faculty of Enigneering

Chulalongkorn University !

10 Mar 2016 @ PSU

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OutlineTraditional networkings Network planes rethought SDN birth SDN impact on networking industry SDN abstractions Global SDN innovations SDN impact to Thailand

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Current Network Focuses

ACCESS!• FTTx • 3G UMTS • 4G LTE • WiMAX 802.16x • FemtoCell • WMN • HetNet • Cognitive Radio

CORE!• IPv6 • NGN / NGI • IMS/EPC • FI • DTN • CCN • SDN • Energy Aware

Networking !

APPLICATION!• WSN • BAN • VANET • ITS • Green Net • SDP, SOA • Cloud

!

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Migration of Core Switching

SDHATM

IP

Ng-SDHMPLS

IP

WDM

MPLSIP

DWDM

IPDWDM

Legacy NOW 3-5 years > 5 years

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Drives of Change• Multimedia, mobile personal computing and WWW

dictate the value of networked services • New access network technologies (xDSL, 2.5/3G/4G,

WiFi, WIMAX, FTTH) allow higher level of demands enter core network

• Explosion in available bandwidth due to optical transmission

• Data dominates voice so new network technologies must rather be designed for data hence packet-based backbone

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Network Industry Evolution

Homogeneous Traffic

Fixed ClientsSingle-Service Network

Heterogeneous Traffic

Mobile ClientsMultiple-Service Network

Human-to-human Communications

Machine-to-machine Communciations

Overprovisioning Capacity Plan

Cloud-based Investment ModelWIFUN@EE-CU

Growing Complexitiesmake it hard to master networkings

[Ref: McKeown 2012]WIFUN@EE-CU

Why debugging networks is hardComplex interaction

– Between multiple protocols on a switch/router.

– Between state on different switches/routers.

Multiple uncoordinated writers of state.

!

Operators can’t…

– Observe all state.

– Control all state.

[Ref: McKeown 2012]WIFUN@EE-CU

Making Networks Work (Today)!

traceroute, ping, tcpdump, SNMP, Netflow

[Ref: McKeown 2012]WIFUN@EE-CU

Hope: SDN would provide a new framework to 1. Verify that networks behave correctly 2. Identify bugs and systematically find root causes

[Ref: McKeown 2012]WIFUN@EE-CU

Networking (P)lanes

Data

Control

Management

Service

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Data Plane

For transmission of data packets sent by users

Packet forwarding

Multicasting packet replication

Fragmentation and reassembly of large packets

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Control PlaneNecessary activities for data plane operations,

but not involving end-user data packets

Routing

Setting packet handling policies e.g. security

Base station beaconing to announce availability of services

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Management Plane

For provisioning and monitoring of networks

Fault, configuration, accounting, performance and security management

• Device management: instantiating new devices and protocols, turning existing devices on/off

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Service PlaneFor improv ing performance or secur i t y of

networks via middle boxes

Proxy service

Load balancing, off-loading operations

• Intrusion detection, firewall

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Existing LimitationsData + control

• coupled proprietarily in networking devices

Management + service

• if non-existed, must be handled manually by (admin) master of complexities

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SDN Birth OpenFlow V1.0.0 2009

Propose to separate data and control planes with open interface Switches with only forwarding elements Control logics (that can be centralised) are moved to x86-based controller OpenFlow is the protocol to send/receive forwarding rules from controller to switches

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Martin Casado PhD @ Stanford

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SDN Conceptual Architecture

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forwarding plane of data packets

controller plane

application (management + service) plane

(open) southbound API

(open) northbound API

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SDN Detailed Architecture (Ref: Open Data Center Alliance Usage Model: Software Defined Networking Rev 1.0)

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SDN Impact On Networking

Industry

Comparative View from Computer Industry

!Nick McKeown Stanford Univ.

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SDN InitiativeAppAppAppAppAppAppAppAppAppAppApp

Control Plane

Control Plane

Control Plane or or

Open Interface

Specialized Control Plane

Specialized Hardware

Specialized Features

Merchant Switching Chips

Open Interface

[Slide by McKeown 2011]WIFUN@EE-CU

Computing Industry

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Specialized Operating System

Specialized Hardware

AppAppAppAppAppAppAppAppAppAppApp

Specialized Applications

Microprocessor

Open Interface

Linux Mac OS

Windows (OS) or or

Open Interface

[Slide by McKeown 2011]WIFUN@EE-CU

Transition Expectation

15 [Ref: McKeown 2011]

Vertically integrated

Closed, proprietary

Rapid innovation

Huge industry

Slow innovation

Small industry

Horizontal

Open interfaces

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How SDN is conceived !horizontal architecture

redefining layer abstraction for control plane

!summarised from keynote talks by

SDN co-inventors (prof McKeown & prof Shenker)

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Daily Seen AbstractionsExecutive summary : conclusion of whole report

Abstract of academic paper : input problem & output solution results

Organisation structure of company: responsibilities & interactions of functional units

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Computer Abstraction

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Hardwares

Operating System

Applications

Low-level Language

High-level Language

User Interfaces

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Network Abstraction

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[Slide by Shenker 2011]

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Abstraction

“The Power of Abstraction”

“Modularity based on abstraction is the way things get done”

Barbara Liskov, MIT

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Module Interface

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Network Abstraction

Plenty in data plane

No powerful ones in control plane

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[Ref: Shenker 2011]

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Network Abstraction

To control network devices … how should we abstract them …

as programmable components

distributively vs centrally

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[Ref: Shenker 2011]

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Million of linesof source code

6,000 RFCs

Billions of gatesCustom Hardware

OS

Routing, management, mobility management, access control, VPNs, …

Feature Feature

[Slide by McKeown 2011]WIFUN@EE-CU

Redefined Control Plane

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Custom Hardware

Custom Hardware

Custom Hardware

Custom Hardware

Custom Hardware

OS

OS

OS

OS

OS

Network OS

Feature Feature

Feature Feature

Feature Feature

Feature Feature

Feature Feature

Feature Feature

[Slide by McKeown 2011]WIFUN@EE-CU

Feature Feature

Network OS

1. Open interface to packet forwarding

3. Consistent, up-to-date global network view 2. At least one Network OS probably many.

Open- and closed-source

SDN Abstraction

Packet Forwarding

Packet Forwarding

Packet Forwarding

Packet Forwarding

Packet Forwarding

[Slide by McKeown 2011]WIFUN@EE-CU

Network OS Centralised Design Choice Example

Gathers local switch information

Constructs global topology view of network

Map central control features into distributed control commands at switches

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Topology Abstractiondifferent network views

for different problems

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Topology Abstraction

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Connectivity Matrix

Routing Matrix

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Global Network View

Abstract Network Views

Networ Operating System

Network Virtualisation

SWITCH

SWITCH

SWITCH

SWITCH

SWITCH

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SDN Module FunctionalitiesControl program: specifies control feature on abstract network model

Network virtualisation: maps abstract network model to global network view

Network operating system: maps global network view to physical switches

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[Ref: Shenker 2011]WIFUN@EE-CU

Global Network View

Network Virtualization

Packet Forwarding

Packet Forwarding

Packet Forwarding

Packet Forwarding

Abstract Network View

Control Programs

Control Programs

Control Programs

firewall.c … if( pkt->tcp->dport == 22) dropPacket(pkt); …

Packet Forwarding

Network OS1.<Match, Action> 2.<Match, Action> 3.<Match, Action> 4.<Match, Action> 5.<Match, Action> 6.… 7.…

1.<Match, Action> 2.<Match, Action> 3.<Match, Action> 4.<Match, Action> 5.<Match, Action> 6.… 7.…

1.<Match, Action> 2.<Match, Action> 3.<Match, Action> 4.<Match, Action> 5.<Match, Action> 6.… 7.…

1.<Match, Action> 2.<Match, Action> 3.<Match, Action> 4.<Match, Action> 5.<Match, Action> 6.… 7.… 1.<Match, Action>

2.<Match, Action> 3.<Match, Action> 4.<Match, Action> 5.<Match, Action> 6.… 7.…

[Slide by McKeown 2012]WIFUN@EE-CU

Switch AbstractionPacket Forwarder

!based on (match, action) principle

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Match-Action PrincipleSwitches

match header of incoming packet

with flow entry in their tables

handle packet as instructed by actions

Controller

construct and update the match-action tables

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Match-Action PrincipleIf no headers match,

packet is enqueued

header is sent to controller,

controller sends a new rule

Subsequent packets handled by the new rule

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Matching Fields (ref: OpenFlow Switch Spec v 1.1.0)

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Example of Actions (ref: Jain 2013)

Forward to physical / virtual port

Enqueue to particular queue in the port

Drop

Modify field e.g. VLAN tags, ToS bits, TTL

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Flow Table Example (ref: Jain 2013)

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Global SDN Innovations

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• Ensuring correctness [Frenetic][HFT][Netcore]Nate Foster, Andrew Ferguson, Mike Freedman, Jen Rexford, Rob Harrison, Dave Walker, ++

• Software Fault Localization [W3]Scott Shenker, Colin Scott, Kyriakos Zarifis, Andreas Wundsam.

• Checking behavior [NICE]Marco Canini, Daniele Venzano, Peter Peresini, Dejan Kostic, Jen Rexford.

• Checking Invariants [VeriFlow] Ahmed Khurshid, Wenxuan Zhou, Matthew Caesar, P. Brighten Godfrey

• Consistent updatesMark Reitblatt, Rick McGeer, ++

• Troubleshooting [OFRewind] Andreas Wundsam, Dan Levin, Srini Seetharaman, Anja Feldma

[Slide by McKeown 2012]WIFUN@EE-CU

Current Academic & Industry Supports

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Software OpenFlow Switches (ref: Jain 2013)

Indigo LINC

Pantou Of13softswitch

XORPlus Open vSwitch

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Hardware OpenFlow Switches (ref: Jain 2013)

Arista 7050 Brocade MLXe, Brocade CER, Brocade CES

Extreme Summit x440, x460, x670 Huawei openflow-capable router platforms

HP 3500, 3500yl, 5400zl, 6200yl, 6600, and 8200zl HP V2 line cards in the 5400zl and 8200zl

IBM 8264 Juniper (MX, EX)

NEC IP8800, NEC PF5240, NEC PF5820 NetGear 7328SO, NetGear 7352SO

Pronto (3290, 3295, 3780) Switch Light platform

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Conclusion

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SDN Impact to ThailandProgrammability of network devices opens new chances for academia to experiment / test research ideas in networks at scale

Lower barrier to entry for new software-based businesses in network industry

More fun in teaching networking

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ReferencesNick McKeown, “Making SDNs Work,” Keynote Talk, ONS 2012.

Nick McKeown, "How SDNs Will Tame Networks,” Keynote Talk, Hot Interconnects, 2012.

Raj Jain, “Lecture Note: Introduction to OpenFlow,” Washington University, 2013.

Scott Shenker, “The Future of Networking and the Past of Protocols,” ONS 2011.

OpenFlow Specifications

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