a hot topic in computer networks today: software- defined networking

國立清華大學高速通訊與計算實驗室NTHU High-Speed Communication & Computing Laboratory

A Hot Topic in Computer Networks Today: Software-

Defined Networking

Prof. Jang-ping Sheu

High-Speed Communication & Computing Laboratory

National Tsing Hua University

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Outline

Background and motivation

What is SDN ?

An open standard- OpenFlow

The applications of SDN

Challenges

Research resources

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Outline


What is SDN ?

An open standard - OpenFlow


Challenges

Research resources

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Internet in Recent Decade Data increasing continuously: Data Center, Cloud

Computing, and Big Data E-business, Video on demand, MOOCs (Massive Open Online

Courses)

More protocols created with Heterogeneity networks

developing VANET (Vehicular Ad-hoc NETwork), WSN (Wireless Sensor

Network), CRN (Cognitive Radio Network)

5Source: Intel 2012 March

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Traditional Networks - Features

Closed equipment Software bundled with hardware Vendor-specific interface

Only vendors can develop for its constrained environments Over specified

Various and complex protocols: OSPF, BGP, DiffServ, NAT, MPLS, and so on.

No uniform standardization Buggy software in the equipment

Routers are with million of lines of source code Cascading failures, vulnerabilities is popular

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Traditional Networks - inconvenience

Operating a network is too complex and expensive To add or move any device, network must be reconfigured,

such as router, switch and firewall Too expensive to change the topology of network

Not easy to control the communications User cannot write the control code except equipment

vendors Long delays to introduce new features

Difficult to customize: Even vendors and third parties are not able to provide

customized cost effective solutions to address their customers’ problems

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Million of linesof source code

6,000 RFCs（ Request For Comments）

Billions of gates, Bloated, Power Hungry

Vertically integrated, complex, closed, proprietaryNot suitable for experimental ideas

Specialized Packet Forwarding Hardware

OperatingSystem

Feature Feature

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

We Need Modify Existing Equipment

Switch

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Vertically integratedClosed, proprietary

Slow innovationSmall industry

SpecializedOperatingSystem

SpecializedHardware

AppAppAppAppAppAppAppAppAppAppApp

SpecializedApplications

HorizontalOpen interfacesRapid innovation

Huge industry

Microprocessor

Open Interface

Linux MacOS

Windows(OS) or or

Open Interface

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Vertically integratedClosed, proprietary

Slow innovation

AppAppAppAppAppAppAppAppAppAppApp

HorizontalOpen interfacesRapid innovation

ControlPlane

ControlPlane

ControlPlane or or

Open Interface

SpecializedControlPlane

SpecializedHardware

SpecializedFeatures

MerchantSwitching Chips

Open Interface

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Outline


What is SDN ?



Challenges

Research resources

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Software-Defined Networking (SDN)

SDN is an approach to networking in which control is decoupled from hardware and given to a software application called a controller Allows network engineers to support a switching

fabric across multi-vendor hardware and application-specific integrated circuit

Allows a stronger intellectual foundation to networking Allows us to define the right abstractions in different

layers Allows us to transfer technology much faster, in both

directions (academic and Industry) Closing the gap with industry

SDN from Traditional Network Device

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Ethernet Switch

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Data Path (Hardware)

Controller (Software)


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Data Path (Hardware)

Control Path OpenFlow

OpenFlow Protocol (SSL)

Controller


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OpenFlow Protocol (SSL)

Controller

Ethernet Switch


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More Detail in SDN

Specialized Packet

Forwarding Hardware

App App App

Specialized Packet

Forwarding Hardware

App App App

Specialized Packet

Forwarding Hardware

App App App

Specialized Packet

Forwarding Hardware

App App App

Specialized Packet

Forwarding Hardware

OperatingSystem

OperatingSystem

OperatingSystem

OperatingSystem

OperatingSystem

App App App

Network Operating System

Control Programs

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More Detail in SDN

Simple Packet Forwarding Hardware



Simple Packet Forwarding Hardware Simple Packet

Forwarding Hardware

Network Operating System

Control Programs

Packets Delivering in SDN

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Controller

PC

OpenFlow Switch

OpenFlow Switch OpenFlow Switch

User’s code

Decision?OpenFlowProtocol

User’s Rule

User’s Rule User’s Rule

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Potential Application Model in SDN

Data Centers Public and private clouds

WANs Google WAN Eventually, public WANs

Enterprise networks Greater control, fewer middle boxes

Home networks Outsourced management

Cellular Networks Separation of service from physical infrastructure

Research and Education Networks National backbones College campus networks

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Outline


What is SDN ?



Challenges

Research resource

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OpenFlow - What is it ?

An open standard for that enables researchers to run experimental protocols in the campus networks we use every day

Network administrators can remotely control forwarding tables by it

Currently being implemented by major vendors Enabled switches now commercially available

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OpenFlowController

OpenFlow Switch

FlowTable

SecureChannel

PCOpenFlow

Protocol

SSL

HW

SW

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OpenFlow - Controller

A controller adds and removes flow entries from the Flow Table on behalf of experiments• A static controller might be a generalization of

VLANs.• More sophisticated controllers that dynamically

add/remove flows as an experiment progresses Researchers might control the complete network of

OpenFlow Switches and be free to decide how all flows are processed

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OpenFlow - Switch

Flow Table, with an action associated with each flow entry, to tell the switch how to process the flow

Secure Channel that connects the switch to controller, allowing commands and packets to be sent between a controller and the switch

OpenFlow Protocol, which provides an open and standard way for a controller to communicate with a switch

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OpenFlow - Flow Table Entry

SwitchPort

MACsrc

MACdst

Ethtype

VLANID

IPSrc

IPDst

IPProt

TCPsport

TCPdport

Rule Action Stats

1. Forward packet to port(s)2. Encapsulate and forward to controller3. Drop packet4. Send to normal processing pipeline

Packet + byte counters

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OpenFlow - Cache flow decisions in datapath

“If header = x, send to port 4”

“If header = ?, send to me”“If header = y, overwrite header with z, send to ports 5,6”

FlowTable

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Deployment Modes In-network: OpenFlow-enabled network infrastructure

(upgraded or green-field) Overlay: Legacy network infrastructure with smart edge devices

New boxes, such as gateways Enhanced kernel bridge (e.g., OpenVSwitch in x86 hypervisors)

Examples: In-network: Google uses OpenFlow-enabled controllers switches to

interconnect their data centers Overlay: AT&T, NTT, eBay, Fidelity Investments, and Rackspace use

OpenStack Quantum and Nicira NVP controller to manage the virtual networks in their clouds

Hybrid: Genesis hosting uses NEC controller in intra-data-center scenario

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Outline


What is SDN ?



Challenges

Research resource

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Benefits from SDN

Network Virtualization Switch based Firewall Multipath Forwarding Congestion Control Identify bugs

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Network Virtualization in SDN

The process of combining hardware and software network resources to be some virtual networks

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Virtualization in Traditional Network

L2 virtualization: VLAN Networks can only support a finite number of

VLANS

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SDN-based Network Virtualization

Each tenant can run his virtual network with controller in SDN.

OpenFlow network removes limitations, allowing administrators to create a flow-based virtual network abstraction.

Computer virtualization Network Virtualization

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SDN-based Network Virtualization

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Switch based Firewall in SDN

OpenFlow switches can emulate Firewall by assigning rules to switches.

Controller

H1

H2

H3

Flow Classifer

Cloud

Block this flow

This packet needs to block

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Traditional Switch Path Forwarding

In traditional switches, forwarding packets use spanning tree algorithm to solve looping problem

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Multipath Forwarding in SDN

Forwarding by rule and central controller’s decision.

Controller

Controller can install multipath roles in SDN switches

Congestion Control by SDN

Controller can get SDN switches information to know if congestion happened.

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Controller Controller gets switches status to decide flow rate

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Identify Bugs by SDN

Identify bugs with systematically tracking down their root cause

When an operational network misbehaves, it is very hard to find the root cause

Allows users to define a Network Breakpoint Capture and reconstruct the sequence of events leading to

the breakpoint

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Outline


What is SDN ?



Challenges

Research resource

Countries in Trial of SDN

68 Trials in 13 Countries

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SDN in University of U.S.A Severing as GENI (Global Environment for Network

Innovations) Networking Substrate

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Challenges

Complex designing solutions

Limited TCAM size

Controller delay and overhead

Multi-controller working together

Migrating from legacy to SDN

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SDN - Data-Plane Challenges

State of Specification Maturity Concerns OF 1.0 single flow table, … OF 1.1 leverages multiple tables

Silicon Concerns Spec is much ahead of silicon development… OF Spec is a

moving target for merchant silicon Merchant silicon is not optimized for OF… supports of

current networking features is a higher priority Specific issues

Scalability of Flow-Matches (limited by TCAM size) Cost concerns

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SDN – Control-Plane Challenges

Control Plane scalability Centralized vs. distributed controllers... Single view of the state of the network, forwarding tables,

… is this a distributed database problem? Interoperability

SDN/NON-SDN Inter-Controller Between different controllers Orchestrating SDNs managed by different controllers …

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SDN- Application-Environments Challenges

Network Resource Abstraction & Conflict Resolution Resource abstraction Conflict resolution among different application actions

Development tools and New Application Paradigm Computing system style application… New class of Network Programming Languages… New tools New development skills… New talents... New education

curriculum…

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Outline


What is SDN ?



Challenges

Research resources

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Research Platform for SDN Mininet

Network emulator Designed for emulating SDN networks Easy to use High performance (100 nodes on a laptop)

Network OS for Research NOX (C++/Python) http://noxrepo.org Maestro (Rice University) Helios (NEC) Beacon (Java) coming soon, …

Network OS Commerce ONIX [OSDI 2010, Google, Nicira, NEC] Expect others

http://noxrepo.org/

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OpenFlow Testbed Candidate controllers:

Nicira’s Nox: C++ and python prototyping NTT’s Ryu : python more production level

Candidate switches: Standalone switches

Pica8 (3290): OpenFlow v1.1, a spin-off of Quanta HP (5400zl): either OpenFlow mode or legacy mode. NEC(IP8800): either OpenFlow mode or legacy mode. Pronto: legacy routing stack and OpenFlow enabled features can not be

support in the same VLAN Brocade (CES/CER/MLX/XMR/MLXe): fully support hybrid mode

PC-based switches (decreasing programmability) OVS (OpenVSwitch): pure software based OpenFlow enabled data path Netronome: network processor PCI card NetFPGA (Stanford): research oriented cards

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Thank you !

2011I International Conference on Computer Science an d Network Technology

a hot topic in computer networks today: software- defined networking

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