Transcript pac.c A Unified Control Architecture for Packet & Circuit

Demystifying SDN
Saurav Das
[email protected]
AT&T Talk
3/27/14
1
A number of slides are courtesy of
www.sdnacademy.com
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Outline
• What is SDN? (or how was it originally intended)
• Different Shades of SDN
• SDN Myths and Misconceptions
What is SDN?
(B) State-Distribution Abstraction: Global View
Network OS running on distributed controllers
Configuration; Control over Forwarding; Monitoring
(A) Forwarding Abstraction: Match-Action Tables
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4
What is an Abstraction?
Data – plane
abstractions
Where are the
control-plane
abstractions?
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5
Where are the Control-Plane Abstractions?
• 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
© 2013 SDN Academy, LLC™. All Rights Reserved.
Developing a Control
Plane Abstraction
Requires
Developing a Data Plane
(Forwarding) Abstraction
PE
Label
Distrib
ution
E-BGP
learned
Route
Advert
VPNIPv4
Route
Advert
TE
Label
Distrib
ution
IGPRoute
Advert,
LinkState
LDP
I-BGP
+ RR
MPBGP
RSVPTE
OSPF
v2
6
Towards a Forwarding Abstraction
7
(A) Forwarding Abstraction
A way to define forwarding behavior
that is not layer or vendor specific
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Interfaces are the Realizations of
Abstractions
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(B) State Distribution Abstraction
Control program should not
have to handle distributedstate details
Proposed
abstraction:
global
network view
Abstracted away by
Network Operating System
State Collection
Dissemination & Synchronization
Application Isolation
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So What is SDN?
Control Abstraction:
Global View
App
App
App
northbound
interface
Controller
southbound
Interface
eg. OpenFlow
Switch
Switch
Forwarding Abstraction:
Match-Action Tables
Switch
Switch
Switch
Interfaces are the
Realizations of
Abstractions
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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,
http://queue.acm.org/detail.cfm?id=2560327
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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.
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13
[1] ‘Pure’ SDN / ‘True’ SDN?
Separation
D <---> C
Simplicity
(B) State-Distribution Abstraction: Global View
Network OS running on distributed controllers
Programmability
Configuration; Control over Forwarding; Monitoring
Lower Capex
Lower Opex
(A) Forwarding Abstraction: Match-Action Tables
© 2013 SDN Academy, LLC™. All Rights Reserved.
14
Different Shades of SDN
• ‘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
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[2] Orchestration/Automation/Gluework
Provides
Automation
Separation
D <---> C
“Controller”
Simplicity
By Orchestrating Across
EMS
EMS
Vendor
Y
Vendor
Z
Programmability
CLI
Vendor
X
Automation
Modified NMS, OpenStack,
cli-scripts  automate
Configuration & provisioning
© 2013 SDN Academy, LLC™. All Rights Reserved.
Lower Capex
Programmability
Changing
Behavior
(if-then-else)
Lower Opex
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[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’
Instead of CLI
expect scripts,
write python
programs
CLI
Replacement
Under traditional networking control PBR
overide
L2
L3
Tunnel
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ECMP
ACL
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[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
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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
Hybrid
Solutions /
‘Ships-in-thenight’
‘Controller’
© 2013 SDN Academy, LLC™. All Rights Reserved.
Some VLANs have
SDN control
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[3] Traditional Networking + ‘SDN Hook’
Separation
D <---> C
Legacy Preserving with Claimed Advantages 
A. Customer realizes benefits of SDN on same infrastructure
B. Allows vendor to build SDN on existing products
‘Controller’
CLI
Replacement
‘Controller’
Instead of CLI
expect scripts,
write python
programs
Simplicity
Programmability
Eg. PCE based
Point
Solutions
Lower Capex
Hybrid
Solutions /
‘Ships-in-thenight’
‘Controller’
© 2013 SDN Academy, LLC™. All Rights Reserved.
Some VLANs have
SDN control
Lower Opex
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Separation
D <---> C
[4] Overlay Networking
OpenStack,
CloudStack,
VMWare
R2
R1
Orchestrator
B2
B1
B3
R3
Simplicity
‘Controller’
R1 B1
B3
Underlying L2/L3
fabric
vSwitch,
vRouter
Context: Data center network
virtualization for public/private
cloud; presented from the
viewpoint of the cloud provider
(not the tenant)!
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Programmability
Lower Capex
Lower Opex
R2 R3
B2
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[5] Traditional Networking + White Box
Separation
D <---> C
Simplicity
Control Plane (Software)
Data Path (Hardware)
White -box
Programmability
Lower Capex
Lower Opex
Merchant Silicon
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[5.5] Traditional Networking + White Box
+ Orchestration
Separation
D <---> C
Simplicity
Control Plane (Software)
Data Path (Hardware)
White -box
Programmability
Lower Capex
Lower Opex
Merchant Silicon
© 2013 SDN Academy, LLC™. All Rights Reserved.
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[6] Decoupled Traditional Networking
Separation
D <---> C
Simplicity
Traditional networking control plane
1.
Software
stacks
2.
Merchant
Silicon
Usually
proprietary,
could be OF,
See IETF ForCES
© 2013 SDN Academy, LLC™. All Rights Reserved.
Programmability
Lower Capex
Lower Opex
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[6.5] Decoupled Traditional Networking
+ Global View
Separation
D <---> C
‘Controller’
Simplicity
Traditional networking control plane
1.
Software
stacks
2.
Merchant
Silicon
Usually
proprietary,
could be OF,
See IETF ForCES
© 2013 SDN Academy, LLC™. All Rights Reserved.
Programmability
Lower Capex
Lower Opex
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[7] Open Source Networking
Separation
D <---> C
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
Simplicity
Programmability
Lower Capex
Lower Opex
© 2013 SDN Academy, LLC™. All Rights Reserved.
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Different Shades of SDN
Separate
D <---> C
Simplicity
Programmability
Lower
Capex
Lower
Opex
© 2013 SDN Academy, LLC™. All Rights Reserved.
27
Myths & Misconceptions
• SDN is Network Virtualization
• SDN == NFV
• SDN is about centralized control
• OpenFlow is not mature
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OpenFlow has evolved towards production readiness.
state
1.0
flows
Q4 ‘09
ports
1.1
Q1 ‘11
+ Group Tables
+ Multiple Tables/Pipelines:
1.2
1.3
+ optical ports
+ synchronized tables
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Interface
msg
single message queue
w/optional barriers
+ forward 1-in-n (ECMP)
+ match QinQ, MPLS, SCTP
+ match virtual ports
+ per-flow metering
+ tunnel-id
Q2 ‘12
Q4 ‘13
forward {0, 1, n}
match Eth, VLAN, IP, L4
+ IPv6
+ multiple controllers
Q4 ‘11
1.4
behavior
+ extensible match
+ extensible actions
+ multiple channels
(auxiliary connections)
+ bundle messages
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 …
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31
Source: Ed Crabbe, Google
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Source: Ed Crabbe, Google
Source: Guru Parulkar
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Source: Guru Parulkar
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Q&A