OIF-plenary-Jan-20-2015_SDN-WAN-Loukas_oif2015.083

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© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 1Cisco Confidential© 2011 Cisco and/or its affiliates. All rights reserved. 1
SDN innovations in WAN.
How "white" should the SDN WAN "boxes" really be?
Loukas Paraschis
Cisco
OIF Plenary presentation January 20, 2015 - oif2015.083
© Loukas Paraschis, cisco, 2015 OIF plenary
© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2
This presentation reviews the increasingly important role of software innovations, and SDN control-
plane evolution in Wide Area Networks (WAN).
It will also debate the meaning, importance, and “hype” in the notion of “white-box” hardware that
has often been associated with significant SDN cost-savings.
Many exciting SDN technologies are currently being developed to enable a future programmable
WAN infrastructure, including open-source controllers, like Open Day Light, new protocols like
NETCONF/YANG, PCE-P/C, BGP-LS, Open Flow, and Source Packet Routing.
Our analysis concludes that, unlike SDN in data-center, SDN in WAN is mainly about enhancing
service automation and traffic engineering optimization, rather than about “white-boxes”.
We will specifically take a closer look on how some of these SDN innovations, and network
hardware, combined, may indeed advance WAN service delivery, automation, operations, and
traffic engineering, potentially extending to multi-layer transport optimization.

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http://www.networkcomputing.com/data-centers/sdn-can-we-skip-the-hard-part/d/d-id/1269189
SDN
OpenFlow
Openstack
APIs
Virtualization
abstraction
HYPERVISOR
Datacenters
Network OS
X86
AUTOMATION
Source: Heavy Reading
Where Networks meet IT
I2RS
Febr. 2014 OIF Workshop - "Transport SDN -
Cutting Through the Hype“
http://www.oiforum.com/public/OIF_NW_Workshop2014_reg.html
“As SDN moves along the curve from curiosity to hype to reality,
Carriers and their vendors need to be able to cut through the hype
and identify what is needed to make Transport SDN a
desirable and deployable technology. The workshop will
present views across the industry of what the enabling
technologies and standards will be, including practical
use cases and applications for Transport SDN”.
 This presentation aims to summarize (in 10 minutes) the key aspects, and use-cases of SDN Transport in the Evolved Programmable WAN.
(Note: no time to discuss here the important related NfV, and DC aspects).
 SDN important advancement; open, agile, network automation, optimization, and orchestration.
 SDN WAN main novelty is the evolution of IP/MPLS to include centralized (global, state-full) TE control.
 Optical central control (NMS) has always existed. So, SDN not radically new.
 SDN transport valuable in the WAN optimization of converged packet-optical architectures, especially with the new
generation of fully flexible DWDM; e.g. multi-layer restoration.

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© 2011 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 5© Loukas Paraschis, cisco, 2015 OIF plenary
 Some basic definitions and observations (minimize the hype)
 WAN main use-cases and value (difference from SDN in DC)
 Main SDN WAN innovations in technology (TE, SPRING, MLO), and network
architecture (hybrid control-plane, unified controller, ODL, apps)
 Some conclusions, adoption, and further work suggestions
…with Service-providers, and especially with (alphabetic order) : Axel Clauberg (DT),
Jeff Finkelstein (Cox), Andreas Gladisch (DT), Mazen Khadam (Cox), Bikash Kooley
(Google), John Leddy (Comcast), Vishnu Shukla (Verizon), Valerio Torres (AMX),
Kathy Tse (AT&T), Gary Ratterree (Microsoft), Amin Vahdat (GOOG).
… with Cisco, and especially S. Alvarez, J. Evans, A. Gous, C. Filsfils, G. Galimberti,
A. Maghbouleh, J. Medved, C. Metz, S. Spraggs, M. Thompson, W. Wakim, D. Ward.
… with industry, and especially at IETF, IEEE, OSA OFC, OIF
Disclaimer: This acknowledgement is NOT suggesting that these individuals have necessarily
reviewed or endorsed this presentation. Any errors are sole responsibility of the author.

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Traditional Control Plane
Architecture
(Distributed)
SDN Control Plane Architecture
(Centralized)
OpenFlow
Routing Control Plane Evolution
• SDN Optimistic View
Simpler, more flexible, more scalable, cheaper
• SDN Pessimistic View
Re-inventing the wheel, moving complexity around
• SDN Optimistic View
Simpler, more flexible, more scalable, cheaper
• SDN Pessimistic View
Re-inventing the wheel, moving complexity around
Hybrid Control Plane Architecture
Application
Distributed Control Plane
Data Plane
Centralized Control Plane
APIs
7
© 2012 Cisco and/or its affiliates. All rights reserved. 8
Network and Device Programmability
Software APIs Automating the Network Infrastructure
Application Frameworks, Management Systems, Controllers, ...
DeviceDevice
ForwardingForwarding
ControlControl
Network ServicesNetwork Services
OrchestrationOrchestration
ManagementManagement
…
…
OpenFlow
OpenFlow
Operating Systems
API and Data Models
OpenStack PuppetC/Java
Puppet
Neutron
Protocols
“Protocols”
BGP, PCEP,...
Python NETCONF REST DC Fabric
OpFlex
Vendor spcific Plug‐Ins
RESTful
YANG JSON

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Cisco Confidential 9© 2013-2014 Cisco and/or its affiliates. All rights reserved.
“SDN” Value Proposition = Improve Network Services
CPU,GB,bps
Traditional Managed Services New era of NFV & SDN
CPU,GB,bps
Compute Domain
Controller
Storage
Domain Controller
DC Network
Domain Controller
Cross Domain OrchestratorCross Domain Orchestrator
ServiceService ServiceService ServiceService ServiceService Service API
Domain abstracted
API
Cross-domain
Orchestrator
Domain specific
controllers provide
device abstraction
Network and data
centre aware service
placement
WAN
Controller
Benefit: Cloud based service delivery with a dynamic, deterministic, optimized network

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“not sure why folks keep talking about SDN as mostly
a datacenter technology… value in the WAN” - Vijay
Gill, MSFT
Compute
Domain
Controller
Storage
Domain
Controller
DC Network
Domain
Controller
WAN
Controller
“we’re doing SDN to program services instead of re-
architecting the network and the OSS for every new
service… reduce our time-to-market from years to
weeks…” - Axel Clauberg, DT
“Global network optimization versus decentralized
protocols approximating global state… Manage the
network as a fabric rather than a collection of individual
boxes… Traffic differentiation” - Amin Vahdat, GOOG
The new “SDN” WAN Era – Executive Summary
SDN Automation – YANG/NETCONF Programmability
DT @ ONS 2013
Business Drivers:
 Radical simplification of Network and OSS (OPEX)
 Faster deployment of services
“We believe carriers can no longer afford to hard-code services into the OSS if they want to get to market
quickly with new services. The Tail-f NCS solution, with both services and the network modeled in a
standardized high-level language, shortens time to market, increases vendor independence and
dramatically improves the cost structure. This SDN solution is a key component in our next generation
network architecture.” - Axel Clauberg, Vice President at Deutsche Telekom

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Network Services Traffic Differentiation WAN Transport Optimization
SDN WAN Transport Optimization through Traffic Differentiation
Google B4, SDN Global WAN (2013)

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entralized control improves network operations and optimization
Applications Applications
Controller
Evolution
• Distributed Control remains best for many use-cases; e.g. IGP convergence
• Centralized Control introduces new value; e.g. TE placement optimization (see for
example M. Horneffer(DT), “IGPTuningin an MPLS Network”, NANOG 33, February 2005, LasVegas)
Head-End TE Path Placement (an example)
Centralized-control improves Distributed-control insufficiencies
Martin Horneffer (DT), “IGP Tuning in an MPLS Network”, NANOG 33, February 2005, Las Vegas

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Cox Case Study: SDN – PCE vs Distributed path Computation
M. Khaddam et al. SCTE 2014
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10.00%
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90.00%
100.00%
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Link Utilization
Links
Path Compuation Model
Online PCE
C97-726578-00 © 2013 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 18
“SDN” increasingly useful as change frequent and the load close to the max-link-load objective
Trafficchangefrequency
annual
monthly
daily
hourly
Max Link Utililization
25% 50% 75% 100%
Planning
(offline)
SDN WAN
(online)
1© Loukas Paraschis, cisco, 2015 OIF plenary

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Connectionless
best-effort
MPLS TE
QoS
FRR, FC
Capacity Planning
Services
OAM & PerfMon
The new Internet (2009 --)
The textbook Internet (1995-2007)
Early Internet Today - EPNIPNGN era (2000 – 2010)
IP Traffic
• Source Routing for Packet Networks
- A path is expressed as an ordered list of segments
- The network maintains segments
- Each engineered application flow is mapped on a path
• Simple: state no longer in the network, only in the packet
- No requirement for RSVP, LDP
• Scale: less Label Databases, less TE LSP
- Leverage MPLS services & hardware
• Forwarding based on Labels with simple ISIS/OSPF extension
• 50msec FRR service level guarantees
• Leverage multi-services properties of MPLS
Co-existence with MPLS currently deployed
Incremental deployment
datatracker.ietf.org/wg/spring/
Millions of
Applications
flows
A path is mapped
on a list of
segments
The network only
maintains
segments
No application
state

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65
A packet injected anywhere
with top label 65 will reach Z
Nodal segment: Operator allocates a label from the SR
registry to each node. For example Z is given label 65
9001
Adjacency segment: Node automatically allocates a
local label for each adjacency. For example Label 9001
allocated for adjacency O
A packet injected at node C
with label 9001 is forced
through datalink CO
Forwarding state (segment) is established by IGP
 LDP and RSVP-TE are not required
MPLS Dataplane is leveraged without any modification
push, swap and pop: all what we need segment = label
A B C
M N O
Z
D
P
A B C D
Z
M N O P
2
A node holds a state per global segment O(3), & a state per local
segment it originates O(2)
For a flow F, only its ingress node N holds a per-flow state for F. Any
other node does not hold any state for F. While they can be millions of
flows crossing a midpoint, its SR FIB scale is only O(3).
SR with Centralized Controller allows for better network utilization (50% in specific example),
predictability, and operation simplification (2000x less tunnels in specific example).
SR (green) is compared to RSVP-TE (red) for the 72 most important Failures in
a real network
© Loukas Paraschis, cisco, 2015 OIF plenary© Loukas Paraschis, cisco, 2015 OIF plenary

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1. The new Optical layer enables a truly Scalable Transport Infrastructure
 Scalable 9.6+Tb/s per fiber, based on 100+Gb/s DWDM channels
 Flexible, fully non-blocking wavelength switching
BUT Optical also is increasingly most expensive part of CapEx (and to certain extend OpEx).
2. Need for Converged Multi-layer transport optimization
‒ Information sharing (e.g. SRLG, Coordinated Maintenance),
‒ SLA aware routing (e.g. min Latency) or Cost aware routing (e.g. min regens)
3. SDN innovation important for Converged Transport
 The IP/MPLS evolution to SDN is an important innovation!
 Optical control, always mainly centrally controlled (NMS)!
SDN
Controller
100G Routing
CapEx < 25%
100G TCO lower
than 40G, and 10G.
Photonics > 60% of CapEx
• 100G scales transport, and lowers TCO; “Moore’s Law” benefit and “Shannon limit”
• 100G photonics cost dominates, and motivates maximum DWDM utilization; Statistical & sub-
wave multiplexing, Multi-layer network optimization
Graph source: cisco, 2011
IEEE OFC Market Watch 3

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IEEE Comm. Mag., Jan. 2014
L0
L3
Reference: M. Khaddam, OFC 2015 (Thursday 8 am, invited)
SDN
Controller
EMS
Applications
(Multi-layer, SPRING, etc)
WDM
Client

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BB1 BB2
Premium: 30G
BE: 90G
3x 100G Worst-case stable:
120G on 200G
Avg IP util: 120/300= 40%
BB1 BB2
Premium: 30G
BE: 90G
2x 100G Worst-case transient:
120G on 100G. BE loss
Worst-case stable:
120G on 200G
Avg IP util: 120/200= 60%
• Optical has always been primarily controlled centrally, based on NMS/EMS
Control-plane (ASON) eventually developed for SDH/SONET shared-meshed protection use-case
First generation WDM was only point-to-point systems; no networking, and hence no control plane need
Only recently WDM layer got sufficiently flexible to benefit from control-plane functionality (WSON)
• GMPLS efforts (15+ years) to enable IP+Optical have seen little success.
GMPLS has aimed to extend the IP/MPLS control-plane paradigm to optical (overlay/UNI or peer/NNI)
GMPLS adoption has remained limited by use-cases and constraints of legacy WDM layer
• Current SDN evolution of IP/MPLS, and introduction of WANO/PCE, enable beneficial
central control for Converged Optimized Multilayer Transport (without, or with GMPLS)
SDN controller and WANO can interface directly to IP/MPLS and Optical, independently
SDN controller and WANO can interface directly to IP/MPLS, which can use GMPLS to interact with the Optical layer
e.g. http://tools.ietf.org/html/draft-ali-pce-remote-initiated-gmpls-lsp-03
28

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Controller and API enabling technologies
Infrastructure n/w controller
Control
Applications
Applications
• End User Applications
• External ISPs / Content Providers
• Service Provider Applications – OSS/BSS,
Orchestration etc
Network Controller
• Augments distributed control plane; service provisioning
• Control application – function specific
• Infrastructure common controller; e.g. ODL platform
Network
• Simplified distributed control plane
• Augmented by central controllers
• Data plane forwarding packet/ optical/virtual
Controller - “Apps” APIs: REST based
Controller - NE APIs: PCEP, BGP-LS, OF, Netconf/YANG, etc
Network SDN Controller
Control
Applications
Control
Applications
Device APIs
Controller
Application
e.g. Analytics
Controller
Applications
e.g. Overlay
control
Controller
Applications
e.g. underlay
optimization
Applications
Virtual
Networks
Packet
Network
Optical
Network
Controllers
Topology Security
Dev Mgmt Collection
Storage Program
Topology Security
Dev Mgmt Collection
Storage Program
Topology Security
Dev Mgmt Collection
Storage Program
First Generation
• Multiple controller applications under development
• Controllers integrating infrastructure functionality
Extra development workload

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Device
APIs
Applications
Virtual Networks
Packet Network
Optical
Network
Controllers
Controller
Application
e.g. Analytics
Controller
Applications
e.g. Overlay control
Controller
e.g. underlay
optimization
Controller Applications
Topology Security Device Mgmt Collection Data Storage
Infrastructure Controller Platform
Programming
Netconf/Yang PCEPOpenFlowOnePK
First Generation
• Multiple controller applications under development
• Controllers integrating infrastructure functionality
Inefficient and extra development workload
Evolution
• Same controller applications
• Implementation of infrastructure controller
• Removal of infrastructure functions from controller
applications
• Open APIs to infrastructure controller

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WAN SDN “southbound” APIs to NE Protocols …
Key Function Protocol/API Comments
IGP Topology BGP Link-State Wraps up LSDB in BGP transport and pushes to BGP
speaker on SDN WAN Orch Platform
Create, Modify and Delete TE
or SR Tunnels
Stateful Extensions to PCEP Introduced as part of Stateful PCE effort
Classification and Action Openflow Extensions Leveraging per-flow MATCH/Action semantics
Security BGP FlowSpec Employs BGP RR to distribute flowspecs to O(# of edge
or peering routers)
Read/Write of Persistent
Configuration Data on
Network Devices
Netconf/Yang Finally gaining traction with vendor implementations and
now on OpenDaylight Platform
WAN Orchestration API REST Standard web service APIs exposes WAN Orch
platform functions and services to applications
WAN Orchestration API RESTCONF Employs REST API principles enabling application
programmability of YANG Data Models
33© Loukas Paraschis, cisco, 2015 OIF plenary
WAN SDN “southbound” APIs to NE Protocols …
Key Function Protocol/API Comments
IGP Topology BGP Link-State Wraps up LSDB in BGP transport and pushes to BGP
speaker on SDN WAN Orch Platform
Create, Modify and Delete TE
or SR Tunnels
Stateful Extensions to PCEP Introduced as part of Stateful PCE effort
Classification and Action Openflow Extensions Leveraging per-flow MATCH/Action semantics
BGP FlowSpec Employs BGP RR to distribute flowspecs to O(# of edge
or peering routers)
Read/Write of Persistent
Configuration Data on
Network Devices
Netconf/Yang Finally gaining traction with vendor implementations and
now on OpenDaylight Platform
WAN Orchestration API REST Standard web service APIs exposes WAN Orch
platform functions and services to applications
WAN Orchestration API RESTCONF Employs REST API principles enabling application
programmability of YANG Data Models
34
We should not care anymore much about which protocol
does what…
• Focus on the needs, and the business outcome; the workflow, application and API layer
• SDN orchestration/controller platforms “abstracts away” all of the protocol details
• Protocols are generally open and now even the controller can be open source; e.g.
OpenDaylight
• Need open standards because networks are heterogeneous

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Cisco Confidential 35© 2013-2014 Cisco and/or its affiliates. All rights reserved.
WAN SDN – many potential Use Cases (Northbound Apps)
Core
Long Haul DWDM
Data CenterMetro and AccessCPE
Metro DWDM
Data Centre
Virtualized n/w
Virtual 2 virtual n/w
interconnect
Service chaining
appliances
Analytics collection
Core Infrastructure
Single/multi layer optimization
Bandwidth & Demand engineering
PCE
Agg and access
Infrastructure
Automated configuration
Service definition
Service assurance
CPE
NFV
Services
provisioning
Analytics
Edge
Edge
NFV
Services
Provisioning
Subscriber
Management
Analytics
Immediate SDN value example - Cox Virtualized Service
Architecture Reference: J. Finkelstein - Lightreading public seminar Aug. 2014
Service
Aggregator
Service
Steering to
Cloud
Cloud Services
Service Provider Network
SDN
Controller
CONTROLLER WITH
TOPOLOGY AND
TOMOGRAPHY DATA
INTELLIGENCE TO
CALCULATE ROUTES,
OPTIMAL PATHS, SERVICES
AWARE

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Optimal and Automated Network maintenance of routers, jointly with optical (SRLG info).
 Reduce operational overhead, and human error.
Cariden & SDN Platform: Analyze historical data, find the best time to remove R1 for 2
hours, and automate operation (according to customized workflow).
API (RESTful ) Query: What is the best time for R1 to be taken out of service for 2 hours?
Time(1) Time(n)
R1
Low
High
Today’s mode
on the router
Virtual, or
Hybrid
Expansion
Core / TransportCore / Transport
PeeringPeering
DCIDCI
PEPE
Subscriber ServicesSubscriber Services
Virtual PE (vPE)Virtual PE (vPE)
Virtual RR (vRR)Virtual RR (vRR)
Align DP
to use-case
Choose CP
per use-case:
Low
High
Single-chassis
High-end System
Single-chassis
Low-end System
Virtual Routing
Multi-chassis
1. Services Catalog 3. Data Plane2. Control Plane

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• Centrally optimized actions before, during
and after service provision to ensure network
supports services within the bounds of SLAs
• Functions:
Demand calendaring – ensuring future capacity is
available for scheduled services
Demand Admission and placement – verifying there
are sufficient resources to place a demand
Network Optimisation – moving demands to make
more efficient use of resources
Capacity planning – how much capacity you need in
future to continue to meet the committed SLAs?
Traffic ManagementTraffic Management
Capacity PlanningCapacity Planning
Demand Admission
and Placement
Demand Admission
and Placement
Network OptimisationNetwork Optimisation
Demand CalendaringDemand Calendaring
Next month
Next week
Offline
Real-time
Now
Based on MATE Design Planning Tool
• Process:
1.Receive demand request(s). In
this case a request per candidate
DC.
2.Add corresponding new
demand(s) to network
3.Simulate for worst-case
4.Respond with WC util
• NYC exceeds acceptable
WC util and WC delay
thresholds
• SJC exceeds acceptable
WC delay threshold
• CHI and KCY are able to
support the requested
demands
• KCY is preferred because
the worst-case utilisation is
lower than for CHI
DC: CHI
WC delay: 22.0ms
WC path util: 91.4%
WC net util: 91.4%
DC: NYC
WC delay: 29.5ms
WC path util: 101.8%
WC net util: 101.8%
DC: SJC
WC delay: 33.0ms
WC path util: 90.8%
WC net util: 90.8%
DC: KCY
WC delay: 22.2ms
WC path util: 90.8%
WC net util: 90.8%

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Network Aware Service Placement Benefits from centralized
optimization
Centrally optimized TE can typically support 30-35% more traffic for the same
provisioned bandwidth (when compared to other placement algorithms).
135% 130% 130%
100%
0%
20%
40%
60%
80%
100%
120%
140%
160%
180%
Random WRR Lowest latency Demand eng
Avg. Network Worst‐Case Utilisation
 SDN is the most important new networking evolution for agility, automation, optimization, and
service orchestration.
 Much industry-wide development and innovation; open, multi-vendor, even open-source:
 unified controller (ODL) and applications framework, advanced automation and optimization
 software and APIs innovation in network programmability
 full spectrum of hardware sophistication useful; “white” boxes not the main value in SDN WAN.
 Standards mainly IETF, notably NETCONF/YANG, SPRING, BGP-LS, and PCEP. Carrier driven industry
definition e.g. Open-Config, ONF, OIF. YANG data models vision!
 Incremental, phased adoption possible
 Routing important evolution allowing to centralized (global, state-full) control automation & optimization.
 Optical control always central mainly; SDN maintains PMO, need extensions, notably YANG, and other
layer-3 innovations e.g. BGP-LS.
 SDN particularly great enabler for multilayer IP+Optical transport, removing the GMPLS gaps.

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22
“Don’t bother me with new ideas; I’ve got a battle to fight!”
Thank you.

OIF-plenary-Jan-20-2015_SDN-WAN-Loukas_oif2015.083

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