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Rob Sherwood Saurav Das Yiannis Yiakoumis. OpenFlow in Service Provider Networks AT&T Tech Talks October 2010. Talk Overview. Motivation What is OpenFlow Deployments OpenFlow in the WAN Combined Circuit/Packet Switching Demo Future Directions. Million of lines of source code. - PowerPoint PPT Presentation
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OpenFlow in Service Provider Networks
AT&T Tech TalksOctober 2010
Rob SherwoodSaurav Das
Yiannis Yiakoumis
Talk Overview
• Motivation• What is OpenFlow• Deployments• OpenFlow in the WAN
– Combined Circuit/Packet Switching– Demo
• Future Directions
Million of linesof source code
5400 RFCs Barrier to entry
500M gates10Gbytes RAM
Bloated Power Hungry
We have lost our way
Specialized Packet Forwarding Hardware
OperatingSystem
App App App
Routing, management, mobility management, access control, VPNs, …
SoftwareControl
Router
HardwareDatapath
Auth
entica
tion,
Secu
rity, A
ccess
Contro
l
HELLO
MPLS
NATIPV6
anycastmulticas
tMobile IP
L3 VPN
L2 VPN VLANOSPF-TE
RSVP-TEHELLOHELLO
Firewall
Multi layer m
ulti
region
iBGP,
eBGP
IPSec
Many complex functions baked into the infrastructureOSPF, BGP, multicast, differentiated services,Traffic Engineering, NAT, firewalls, MPLS, redundant layers, …
An industry with a “mainframe-mentality”
DeploymentIdea Standardize
Wait 10 years
Glacial process of innovation made worse by captive standards process
• Driven by vendors• Consumers largely locked out• Glacial innovation
New Generation Providers Already Buy into It
In a nutshellDriven by cost and controlStarted in data centers….
What New Generation Providers have been Doing Within the Datacenters
Buy bare metal switches/routers Write their own control/management applications on a
common platform
6
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
App App App
Change is happening in non-traditional markets
App
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware
Simple Packet Forwarding Hardware
App App
Simple Packet Forwarding Hardware Simple Packet
Forwarding Hardware
Network Operating System
1. Open interface to hardware
3. Well-defined open API2. At least one good operating system
Extensible, possibly open-source
The “Software-defined Network”
Windows(OS)
Windows(OS)
Linux MacOS
x86(Computer)
Windows(OS)
AppApp
LinuxLinuxMacOS
MacOS
Virtualization layer
App
Controller 1
AppApp
Controller2
Virtualization or “Slicing”
App
OpenFlow
Controller 1NOX(Network OS)
Controller2Network OS
Trend
Computer Industry Network Industry
Simple common stable hardware substrate below+ programmability + strong isolation model + competition above = Result : faster innovation
What is OpenFlow?
Short Story: OpenFlow is an API
• Control how packets are forwarded• Implementable on COTS hardware• Make deployed networks programmable
– not just configurable
• Makes innovation easier• Result:
– Increased control: custom forwarding– Reduced cost: API increased competition
Ethernet Switch/RouterEthernet Switch/Router
Data Path (Hardware)Data Path (Hardware)
Control PathControl PathControl Path (Software)Control Path (Software)
Data Path (Hardware)Data Path (Hardware)
Control PathControl Path OpenFlowOpenFlow
OpenFlow ControllerOpenFlow Controller
OpenFlow Protocol (SSL/TCP)
Controller
PC
HardwareLayer
SoftwareLayer
Flow Table
MACsrc
MACdst
IPSrc
IPDst
TCPsport
TCPdport Action
OpenFlow Firmware
**5.6.7.8*** port 1
port 4port 3port 2port 1
1.2.3.45.6.7.8
OpenFlow Flow Table Abstraction
OpenFlow BasicsFlow Table Entries
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 pipeline5. Modify Fields
+ mask what fields to match
Packet + byte counters
ExamplesSwitching
*
SwitchPort
MACsrc
MACdst
Ethtype
VLANID
IPSrc
IPDst
IPProt
TCPsport
TCPdport Action
* 00:1f:.. * * * * * * * port6
Flow Switching
port3
SwitchPort
MACsrc
MACdst
Ethtype
VLANID
IPSrc
IPDst
IPProt
TCPsport
TCPdport
Action
00:20.. 00:1f.. 0800 vlan1 1.2.3.4 5.6.7.8 4 17264 80 port6
Firewall
*
SwitchPort
MACsrc
MACdst
Ethtype
VLANID
IPSrc
IPDst
IPProt
TCPsport
TCPdport Forward
* * * * * * * * 22 drop
ExamplesRouting
*
SwitchPort
MACsrc
MACdst
Ethtype
VLANID
IPSrc
IPDst
IPProt
TCPsport
TCPdport Action
* * * * * 5.6.7.8 * * * port6
VLAN Switching
*
SwitchPort
MACsrc
MACdst
Ethtype
VLANID
IPSrc
IPDst
IPProt
TCPsport
TCPdport
Action
* * vlan1 * * * * *
port6, port7,port9
00:1f..
OpenFlowSwitch.org
Controller
OpenFlow Switch
PC
OpenFlow UsageDedicated OpenFlow Network
OpenFlow Switch
OpenFlow Switch
OpenFlowProtocol
Aaron’s code
Rule Action Statistics
Rule Action Statistics Rule Action Statistics
Network Design Decisions
Forwarding logic (of course)
Centralized vs. distributed control
Fine vs. coarse grained rules
Reactive vs. Proactive rule creation
Likely more: open research area
Centralized vs Distributed Control
Centralized Control
OpenFlow Switch
OpenFlow Switch
OpenFlow Switch
Controller
Distributed Control
OpenFlow Switch
OpenFlow Switch
OpenFlow Switch
Controller
Controller
Controller
Flow Routing vs. AggregationBoth models are possible with OpenFlow
Flow-Based
Every flow is individually set up by controller
Exact-match flow entriesFlow table contains one entry
per flowGood for fine grain control, e.g.
campus networks
Aggregated
One flow entry covers large groups of flowsWildcard flow entriesFlow table contains one entry per category of flowsGood for large number of flows, e.g. backbone
Reactive vs. Proactive Both models are possible with OpenFlow
Reactive
First packet of flow triggers controller to insert flow entries
Efficient use of flow tableEvery flow incurs small
additional flow setup timeIf control connection lost, switch
has limited utility
Proactive
Controller pre-populates flow table in switchZero additional flow setup timeLoss of control connection does not disrupt trafficEssentially requires aggregated (wildcard) rules
OpenFlow Application: Network Slicing
• Divide the production network into logical sliceso each slice/service controls its own packet forwardingo users pick which slice controls their traffic: opt-ino existing production services run in their own slice
e.g., Spanning tree, OSPF/BGP
• Enforce strong isolation between sliceso actions in one slice do not affect another
• Allows the (logical) testbed to mirror the production network
o real hardware, performance, topologies, scale, users
o Prototype implementation: FlowVisor
Add a Slicing Layer Between Planes
DataPlane
Rules Excepts
Slice 1Controller
Slice 2Controller
Control/DataProtocol
SlicePolicies
Slice 3Controller
Network Slicing Architecture
• A network slice is a collection of sliced switches/routers
• Data plane is unmodified
– Packets forwarded with no performance penalty
– Slicing with existing ASIC
• Transparent slicing layer
– each slice believes it owns the data path
– enforces isolation between slices
• i.e., rewrites, drops rules to adhere to slice police
– forwards exceptions to correct slice(s)
Slicing Policies
• The policy specifies resource limits for each slice:
– Link bandwidth
– Maximum number of forwarding rules
– Topology
– Fraction of switch/router CPU
– FlowSpace: which packets does the slice control?
FlowSpace: Maps Packets to Slices
Real User Traffic: Opt-In
• Allow users to Opt-In to services in real-timeo Users can delegate control of individual flows to Sliceso Add new FlowSpace to each slice's policy
• Example:o "Slice 1 will handle my HTTP traffic"o "Slice 2 will handle my VoIP traffic"o "Slice 3 will handle everything else"
• Creates incentives for building high-quality services
FlowVisor Implemented on OpenFlow
CustomControlPlane
StubControlPlane
DataPlane
OpenFlowProtocol
Switch/Router
Server
Network
Switch/Router
Servers
OpenFlowFirmware
Data Path
OpenFlowController
Switch/RouterSwitch/Router
OpenFlowFirmware
Data Path
OpenFlowController
OpenFlowController
OpenFlowController
FlowVisorOpenFlow
OpenFlow
FlowVisor Message Handling
OpenFlowFirmware
Data Path
AliceController
BobController
CathyController
FlowVisorOpenFlow
OpenFlow
Packet
Exception
Policy Check:Is this rule allowed?
Policy Check:Who controls this packet?
Full Line RateForwarding
Rule
Packet
OpenFlow Deployments
OpenFlow has been prototyped on….
• Ethernet switches– HP, Cisco, NEC, Quanta, + more underway
• IP routers– Cisco, Juniper, NEC
• Switching chips– Broadcom, Marvell
• Transport switches– Ciena, Fujitsu
• WiFi APs and WiMAX Basestations
Most (all?) hardware switches now based on Open vSwitch…
Most (all?) hardware switches now based on Open vSwitch…
Deployment: Stanford
• Our real, production networko 15 switches, 35 APso 25+ userso 1+ year of useo my personal email and
web-traffic!
• Same physical network hosts Stanford demoso 7 different demos
Demo Infrastructure with Slicing
Deployments: GENI
(Public) Industry Interest
• Google has been a main proponent of new OpenFlow 1.1 WAN features– ECMP, MPLS-label matching
– MPLS LDP-OpenFlow speaking router: NANOG50
• NEC has announced commercial products– Initially for datacenters, talking to providers
• Ericsson– “MPLS Openflow and the Split Router Architecture: A Research
Approach“ at MPLS2010
OpenFlow in the WAN
OPEX: 60-70%
CAPEX: 30-40%
… and yet service providers own & operate 2 such networks : IP and Transport
DDC
DDC
DDC
DDC
IP/MPLSIP/MPLS IP/MPLS
IP/MPLS
IP/MPLSIP/MPLS
IP/MPLSIP/MPLS
CDD
CDD
CDD
DD
DD
DD
DD
C C
DD
DD
GMPLS
Motivation
• managed and operated independently
• resulting in duplication of functions and resources in multiple layers
• and significant capex and opex burdens
… well known
IP & Transport Networks are separate
DDC
DDC
DDC
DDC
IP/MPLSIP/MPLS IP/MPLS
IP/MPLS
IP/MPLSIP/MPLS
IP/MPLSIP/MPLS
CDD
CDD
CDD
DD
DD
DD
DD
C C
DD
DD
GMPLS
Motivation
• IP links are static
• and supported by static circuits or lambdas in the Transport network
IP & Transport Networks do not interact
What does it mean for the IP network?IP backbone network design
– Router connections hardwired by lambdas– 4X to 10X over-provisioned
• Peak traffic• protection
IP
DWDM
Big Problem
- More over-provisioned links
- Bigger Routers
How is this scalable??*April, 02
Bigger Routers?Dependence on large Backbone Routers• Expensive• Power Hungry
Juniper TX8/T640
TX8
Cisco CRS-1
How is this scalable??
Functionality Issues!Dependence on large Backbone Routers• Complex & Unreliable
Network World05/16/2007
Dependence on packet-switching• Traffic-mix tipping heavily towards video
• Questionable if per-hop packet-by-packet processing is a good idea
Dependence on over-provisioned links
• Over-provisioning masks packet switching simply not very good at providing bandwidth, delay, jitter and loss guarantees
How can Optics help?
• Optical Switches– 10X more capacity per unit volume (Gb/s/m3)– 10X less power consumption– 10X less cost per unit capacity (Gb/s)– Five 9’s availability
• Dynamic Circuit Switching– Recover faster from failures– Guaranteed bandwidth & Bandwidth-on-demand– Good for video flows– Guaranteed low latency & jitter-free paths– Help meet SLAs – lower need for over-provisioned IP links
DDC
DDC
DDC
DDC
IP/MPLSIP/MPLS IP/MPLS
IP/MPLS
IP/MPLSIP/MPLS
IP/MPLSIP/MPLS
CDD
CDD
CDD
DD
DD
DD
DD
C C
DD
DD
GMPLS
Motivation
• IP links are static
• and supported by static circuits or lambdas in the Transport network
IP & Transport Networks do not interact
What does it mean for the Transport network?
IP
DWDM
*April, 02
Without interaction with a higher layer• there is really no need to support dynamic services• and thus no need for an automated control plane• and so the Transport network remains manually controlled via NMS/EMS• and circuits to support a service take days to provision
Without visibility into higher layer services• the Transport network reduces to a bandwidth-seller
The Internet can help…• wide variety of services• different requirements that can take advantage of dynamic circuit characteristics
What is needed
… Converged Packet and Circuit Networks
• manage and operate commonly
• benefit from both packet and circuit switches
• benefit from dynamic interaction between packet
switching and dynamic-circuit-switching
… Requires• a common way to control
• a common way to use
But
… Convergence is hard
… mainly because the two networks have very different architecture which makes integrated operation hard
… and previous attempts at convergence have assumed that the networks remain the same
… making what goes across them bloated and complicated and ultimately un-usable
We believe true convergence will come about from architectural change!
FlowNetwork
DDC
DDC
DDC
DDC
IP/MPLSIP/MPLS IP/MPLS
IP/MPLS
IP/MPLSIP/MPLS
IP/MPLSIP/MPLS
CDD
CDD
CDD
DD
DD
DD
DD
C C
DD
DD
GMPLS
UCP
FlowNetwork
… that switch at different granularities: packet, time-slot, lambda & fiber
Simple,network of Flow Switches
Research Goal: Packet and Circuit Flows Commonly Controlled & Managed
pac.c
52
… a common way to control
Exploit the cross-connect table in circuit switches
Packet FlowsSwitchPort
MACsrc
MACdst
Ethtype
VLANID
IPSrc
IPDst
IPProt
TCPsport
TCPdport
Action
52
Circuit Flows
Signal Type
VCG52 Signal Type
VCG
The Flow Abstraction presents a unifying abstraction
… blurring distinction between underlying packet and circuit and regarding both as flows in a flow-switched network
OpenFlow Protocol
PacketSwitch
CircuitSwitch
Packet & Circuit Switch
NETWORK OPERATING SYSTEM
Variable Bandwidth
Packet Links
Variable Bandwidth
Packet Links
DynamicOptical Bypass
DynamicOptical Bypass
Unified RecoveryUnified
Recovery
UnifiedControl Plane
Unifying Abstraction
Networking Applications
Packet & Circuit Switch
PacketSwitch
VIRTUALIZATION (SLICING) PLANE
Underlying Data Plane Switching
Traffic Engineering
Traffic Engineering
Application-Aware QoSApplication-Aware QoS
… a common way to useUnified Architecture
Congestion Control
Congestion Control
Example Application
..via Variable Bandwidth Packet Links
OpenFlow Demo at SC09
Video Clients Video Server
192.168.3.12192.168.3.10λ1 1553.3 nm
λ2 1554.1 nm
192.168.3.15
OpenFlowController
OpenFlow Protocol
GE to DWDM SFP convertor
GE
O-E
NF2
GE
E-O
NetFPGA based OpenFlow packet switch NF1
25 km SMF
to OSA
to OSA
AWG
WSS based OpenFlow circuit switch
1X9 Wavelength Selective Switch (WSS)
Lab Demo with Wavelength Switches
Openflow Circuit Switch
25 km SMF
OpenFlow packet switch OpenFlow packet switch
GE-Optical
GE-Optical
Mux/Demux
Lab Demo with Wavelength Switches
OpenFlow Enabled Converged Packet and Circuit Switched Network
Stanford University and Ciena Corporation
Demonstrate a converged network, where OpenFlow is used to control both packet and circuit switches.
Dynamically define flow granularity to aggregate traffic moving towards the network core.
Provide differential treatment to different types of aggregated packet flows in the circuit network:
VoIP : Routed over minimum delay dynamic-circuit path Video: Variable-bandwidth, jitter free path bypassing
intermediate packet switches HTTP: Best-effort over static-circuits
Many more new capabilities become possible in a converged network
SANFRANCISCO
HOUSTON
NEW YORK
Controller
OpenFlow Protocol
OpenFlow Enabled Converged Packet and Circuit Switched Network
Demo Video
Issues with GMPLS
• GMPLS original goal: UCP across packet & circuit (2000)
• Today – the idea is dead
•Packet vendors and ISPs are not interested
• Transport n/w SPs view it as a signaling tool available to the mgmt system for
provisioning private lines (not related to the Internet)
• After 10 yrs of development, next-to-zero significant deployment as UCP
• GMPLS Issues
Issues are when considered as a unified architecture and control plane
• control plane complexity escalates when unifying across packets and circuits because it
• makes basic assumption that the packet network remains same: IP/MPLS network – many years of legacy L2/3 baggage• and that the transport network remain same - multiple layers and multiple vendor domains
• use of fragile distributed routing and signaling protocols with many extensions, increasing switch cost & complexity, while decreasing robustness
• does not take into account the conservative nature of network operation
• can IP networks really handle dynamic links? • Do transport network service providers really want to give up control to an automated control plane?
• does not provide easy path to control plane virtualization
Issues with GMPLS
Conclusions
• Current networks are complicated• OpenFlow is an API
– Interesting apps include network slicing
• Nation-wide academic trials underway• OpenFlow has potential for Service Providers
– Custom control for Traffic Engineering– Combined Packet/Circuit switched networks
• Thank you!
Conclusions
• Current networks are complicated• OpenFlow is an API
– Interesting apps include network slicing
• Nation-wide academic trials underway• OpenFlow has potential for Service Providers
– Custom control for Traffic Engineering– Combined Packet/Circuit switched networks
• Thank you!
Backup
• It is well known that Transport Service Providers dislike giving up manual control of their networks
• to an automated control plane• no matter how intelligent that control plane may be• how to convince them?
• It is also well known that converged operation of packet & circuit networks is a good idea
• for those that own both types of networks – eg AT&T, Verizon• BUT what about those who own only packet networks –eg Google
• they do not wish to buy circuit switches• how to convince them?
• We believe the answer to both lies in virtualization (or slicing)
Practical Considerations
OpenFlow Protocol
C
C C
FLOWVISOR
OpenFlow Protocol
CK
CK
CK
PP
CK
P
CKP
Basic Idea: Unified Virtualization
OpenFlow Protocol
C C C
FLOWVISOR
OpenFlow Protocol
CK
CK
CK
PP
CK
P
CKP
ISP ‘A’ Client Controller
Private Line Client Controller
ISP ‘B’ Client Controller
Under Transport Service Provider (TSP) control
IsolatedClient
Network Slices
SinglePhysical
Infrastructureof Packet &
Circuit Switches
Deployment Scenario: Different SPs
Demo Topology
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ISP# 1’s NetOSISP# 1’s NetOS
AppApp AppApp AppApp
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SONET
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TDM
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TDM
ISP# 2’s NetOSISP# 2’s NetOS
AppApp AppApp AppApp
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SONET SONET
TDM
Transport Service Provider’s (TSP) virtualized networkInternet Service Provider’s
(ISP# 1) OF enabled networkwith slice of TSP’s network Internet Service Provider’s (ISP# 2)
OF enabled network with another slice of TSP’s networkTSP’s private line customer
Demo Methodology
We will show:1.TSP can virtualize its network with the FlowVisor while maintaining operator control via NMS/EMS.
a) The FlowVisor will manage slices of the TSP’s network for ISP customers, where { slice = bandwidth + control of part of TSP’s switches }
b) NMS/EMS can be used to manually provision circuits for Private Line customers
2.Importantly, every customer (ISP# 1, ISP# 2, Pline) is isolated from other customer’s slices.
1. ISP#1 is free to do whatever it wishes within its slicea) eg. use an automated control plane (like OpenFlow)b) bring up and tear-down links as dynamically as it wants
2. ISP#2 is free to do the same within its slice3. Neither can control anything outside its slice, nor interfere with other slices4. TSP can still use NMS/EMS for the rest of its network
ISP #1’s Business Model
ISP# 1 pays for a slice = { bandwidth + TSP switching resources }
1. Part of the bandwidth is for static links between its edge packet switches (like ISPs do today)
2. and some of it is for redirecting bandwidth between the edge switches (unlike current practice)
3. The sum of both static bandwidth and redirected bandwidth is paid for up-front.
4. The TSP switching resources in the slice are needed by the ISP to enable the redirect capability.
ISP# 1’s network
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Packet (virtual) topology
Actual topology
Notice the spare interfaces
..and spare bandwidth in the slice
ISP# 1’s network
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Packet (virtual) topology
Actual topology
ISP# 1 redirects bw between the spare interfaces to dynamically create new links!!
ISP #1’s Business Model Rationale
Q. Why have spare interfaces on the edge switches? Why not use them all the time?
A. Spare interfaces on the edge switches cost less than bandwidth in the core1. sharing expensive core bandwidth between cheaper edge
ports is more cost-effective for the ISP2. gives the ISP flexibility in using dynamic circuits to create
new packet links where needed, when needed3. The comparison is between (in the simple network shown)
a) 3 static links + 1 dynamic link = 3 ports/edge switch + static & dynamic core bandwidth
b) vs. 6 static links = 4 ports/edge switch + static core bandwidthc) as the number of edge switches increase, the gap increases
ISP #2’s Business Model
ISP# 2 pays for a slice = { bandwidth + TSP switching resources }
1. Only the bandwidth for static links between its edge packet switches is paid for up-front.
2. Extra bandwidth is paid for on a pay-per-use basis
3. TSP switching resources are required to provision/tear-down extra bandwidth
4. Extra bandwidth is not guaranteed
ISP# 2’s network
Packet (virtual) topology
Actual topology
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ISP# 2 uses variable bandwidth packet links ( our SC09 demo )!!
Only static link bw paid for up-front
ISP #2’s Business Model Rationale
Q. Why use variable bandwidth packet links? In other words why have more bandwidth at the edge (say 10G) and pay for less bandwidth in the core up-front (say 1G)
A. Again it is for cost-efficiency reasons. 1. ISP’s today would pay for the 10G in the core up-front
and then run their links at 10% utilization.2. Instead they could pay for say 2.5G or 5G in the core,
and ramp up when they need to or scale back when they don’t – pay per use.
Recommended