application engineered routing: allowing applications to program the network

Cisco Confidential© 2015 Cisco and/or its affiliates. All rights reserved. 1

Application Engineered Routing: Allowing Applications to Program the NetworkT-SP-32-I

Rob PiaseckiSolutions Architect, Services

May 19, 2016

[email protected]

© 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2

Agenda

• AER: Industry Drivers & Overview

• AER: Architecture & Technical Concepts

Segment Routing

Intelligent SDN Controller

• Use Cases & Implementation

Purpose Built Applications

Demo

• Conclusion

Cisco Confidential 3© 2015 Cisco and/or its affiliates. All rights reserved.

AER: Industry Drivers & Overview


The ProblemThe Network is facing new challenges

EVOLVED PROGRAMMABLE NETWORK

IPv6

UHD

IoE

Cloud

Services

Mobility

Other

Dynamic and changing traffic patterns

Increasingly diverse applications with

application-specific transport requirements

End-to-End control required


IP NGN Era

Networks Need to be RethoughtApplications and Network interaction is key

Edge

Access/ Agg

IP

Core

Designed to support any kind of services

Automation (APIs, Controllers, …)

Designed to support a set of services

Static traffic patterns

Manual configuration (CLI)

EVOLVED PROGRAMMABLE NETWORK

IPv6

EVOLVED SERVICES PLATFORM

APPLICATIONS

Dynamic traffic patterns

App & Network InteractionApps Independent of Network


Specific Approaches to the ProblemA continuum of enhanced solutions

Policy-Based routing MPLS TE

Scalable

Stateless

Programmable

Ease of configuration &

troubleshooting

EPN EraIP NGN Era

Effective solutions with some caveats:

Little or no application / network interaction

Scalability

Configuration & troubleshooting complexity

States to be maintained in each network node

Evolution required

to address the

new paradigm

One device, single domain Many devices, single domain Many devices, across domains

DC CoreHosts Agg DC CoreHosts Agg DC CoreHosts Agg


Applications & Network InteractionImplications for the Network Fabric

Limitations

Limited to a single network

domain

Scalability

Configuration &

troubleshooting complexity

States to be maintained in

each network nodeShortest path with QoS Traffic-engineered tunneling

Impediment to service

creation

Major scalability issues

Operational challenges

Many applications with

dynamic and changing traffic patterns

IP Networks IP Networks & Traffic Engineering

IP Networks Evolution


Segment

Routing

(SW upgrade)

SDN

Controller

Applications1

Applications express

requirements – bandwidth,

latency, interactive …

2The controller collects data from the

network – topology, link states, link

utilization, …

3

Applications are mapped to a path defined

by a list of segments

Network maintains segments only

No application state

The SolutionApplication Engineered Routing


IP/LDP

Application Engineered RoutingEvolve MPLS with Segment Routing

Seattle

New-York

Berlin

Mexico

Madrid

TorontoLondon

TXL

1. A luggage tag is attached with the

final destination

2. Luggage identified and routed to the

next destination

No control over the path –

Luggage is routed over the shortest pathRESULT:

Mission – Route the luggage to Berlin

IP/LDP

Segment Routing

RSVP-TE


RSVP-TE

Application Engineered RoutingEvolve MPLS with Segment Routing

Seattle

New-York

Berlin

Mexico

Madrid

TorontoLondon

20000

SEA MEX

20000

MEX MAD

20000

MAD TXL

1. At each stop, the luggage is

identified and routed to the next

hop

A list of all the paths has to be

maintained

2. A specific tag is assigned to each piece of

luggage,

i.e. Tunnel ID 20000, is created to identify the

path Seattle-Mexico-Madrid-Berlin

Path can be controlled

Complexity and scalability issuesRESULT:


via Mexico and Madrid

IP/LDP

Segment Routing

RSVP-TE


Segment Routing

Application Engineered Routing Evolve MPLS with Segment Routing

Seattle

New-York

Berlin

Mexico

Madrid

TorontoLondon

IP/LDP

Segment Routing

RSVP-TE

TXL

1. A unique and global luggage tag is

attached to the luggage with the list

of stops to the final destination

2. At each stop, the luggage is simply

routed to the next hop listed on the

luggage tag

Path can be controlled

Simple and scalableRESULT:


via Mexico and Madrid

MEX

MAD

TXL

MAD

TXL


Application Engineered Routing Segment Routing – Technical View

Path expressed in

the packetData

Dynamic path

Explicit path

Paths options

Dynamic

(STP computation)

Explicit

(expressed in the packet)

Control Plane

Routing protocols with

extensions

(IS-IS,OSPF, BGP)

SDN controller

Data Plane

MPLS

(segment labels)

IPv6

(+SR header)


Application Engineered Routing JourneyAdding value at your own pace

Enable Segment Routing on EPN Platforms (Software only)

Insert ESP components – Orchestration, SDN controller

Connect with Cisco’s and

third party VNFs

Network Simplification

Network Resiliency

End-User Experience

Network Optimization

Service Velocity

E2E Application Control

Benefits


Application Engineered RoutingSolution Components

EPN

ESP

Network

Applications

Segment Routing (SR) across Cisco platforms

ASR 9K ASR 1KNEXUS

9000

WAE NSO VTS

3rd-party platforms

supporting SR

Bandwidth

calendaring3rd-party applications

3rd-party

controller

Physical Virtual

Southbound

interfacesNetconf/Yang BGP LS PCEP Configlets

Northbound

interfacesRESTful APIs

Low-latency

path selection

Disjoint

recovery path

……NCS 6K …

VNF


Technology Innovation Driving Business Outcomes

Ease of

configuration

Ease of troubleshooting

Network resiliency

Automated 50ms

protection

Optimized CapEx

Reduced OpEx

Better End-User

experience

Programmability

Per application traffic

steering

Economic

Value

Increased Customer

Lifetime Value

SLAs Monetization

Higher link

utilization

Stateless

Scalability

Lower network resources

consumption


Why Cisco?

Comprehensive portfolio for delivering an end-to-end

Application Engineered Routing solution

Open solution to match diverse customer needs (IETF

standard, APIs)

Phased approach to Application Engineered Routing

solution (not a rip & replace solution)

1

2

3


Architecture & Technical Concepts: Segment

Routing


Segment Routing

• Unified

• DC + WAN + Aggregation

• From server in the DC, through WAN and to the service edge

• Policy-aware

• DC: disjoint planes, flow-based congestion avoidance

• WAN: disjoint services, latency-sensitive traffic, scheduled bulk transfer

• Application programs the end-to-end policy

• The end-to-end policy is encoded by the application as an SR segment list in the packet header

• Balance between distributed and centralized intelligence

• Distributed: automated sub-30msec FRR link/node in any topology with optimum backup path

• Centralized: traffic optimization for better use of the installed capacity

• Applicable to MPLS and IPv6 data-planes

• Much simpler to operate than MPLS Classic


• Source Routing: the source chooses a path and encodes it in the packet header as an ordered list of segments.

• Segment: an identifier for any type of instruction

• Service

• Context

• Locator

• IGP-based forwarding construct

• BGP-based forwarding construct

• Local value or Global Index

Segment Routing

Segment = Instructions such as

"go to node N using the shortest path"


• MPLS: an ordered list of segments is represented as a stack of labels

• SR re-uses MPLS data-plane without any change

• IPv6: an ordered list of segments is represented as a routing extension header, see 4.4 of RFC2460

• IGP-based segments require minor extension to the existing link-state routing protocols (OSPF and IS-IS).

Segment Routing


• Simple extension to let IGP install segments in the MPLS dataplane

• Excellent Scale: a node installs N+A FIB entries

• N node segments and A adjacency segments

IGP Segments

A B C

M N O

Z

D

P

Node segment to C

Node segment to Z

Adj Segment

Node segment to C


Node Segment

• Z advertises a global node segment 16065 with its loopback

• Simple ISIS sub-TLV extension

• Default SRGB [16000, 23999] at all nodes is a request from all lead operators for operational simplicity. The protocol and implementation allows for different SRGB at every node

• All remote nodes install in their FIB the node segment 16065 to Z

A B C

Z

D

16065

FEC Z

push 16065

swap 16065

to 16065swap 16065

to 16065pop 16065

A packet injected

anywhere with top

segment 16065 will

reach Z via

shortest-path

Packet to

Z

Packet to

Z

16065

Packet to

Z

16065

Packet to

Z

16065

Packet to

Z


Node Segment

• ECMP

• A node segment to 16078 distributes traffic across all ECMP paths to O

A B C

M N O

Z

D

P

16078


Adjacency Segment

• C allocates a local segment 29003 and maps it to the instruction “complete the segment and forward along the interface CO”

• C advertises the adjacency segment in ISIS

• Simple sub-TLV extension

• C is the only node to install the adjacency segment in FIB

A B C

M N O

Z

D

P

Pop

29003

A packet injected at

node C with segment

29003 is forced

through datalink C-O


Explicit Path as Segment List

• ECMP

• Node segment

• Per-flow state only at head-end

• Not at mid-points

• Source Routing

• Path state is in the packet headerA B C

M N O

Z

D

P

16078

Packet to Z

1606516078

Packet to Z

16065

Packet to Z

Packet to Z

16065

Packet to Z

16065

16078

16072

Packet to Z

16065

16078

16072

1607216072

16065

16065


• Guaranteed Link/Node FRR in any topology

• 50-msec protection

• Simplicity

• Entirely automated

• No directed LDP session

• No RSVP-TE tunnels

• Incremental deployment

• Applicable to LDP primary traffic

• Optimal backup path along post convergence path

• Prevents transient congestion and suboptimal routing

Automated 50-msec Protection for IGP Segments


SR-based MPLS Classic MPLS

Basic mpls transport IGP IGP + LDP

IGP/LDP synchronization N/A Problem to manage

50msec FRR IGP IGP + RSVP-TE

Extra TE states to support FRR No extra state Extra states to manage

Optimum backup path Yes (IP post-convergence) No (SDH-alike)

ECMP-capability for TE Yes No

TE state only at headend Yes No (n^2 problem at midpoint)

Seamless Interworking with classic MPLS and

incremental deployment

Yes N/A

Engineered for SDN Yes No


IP/MPLS architecture that seeks the right balance between distributed intelligence and centralizedoptimization and programming.

• simplifies operation (lower opex)

• enables application-based service creation (new revenue)

• allows for better utilization of the installed infrastructure (lower capex)

An IP/MPLS architecture with wide application

• (SP, OTT/Web, GET) across (WAN, Metro/Agg, DC)

• MPLS and IPv6 dataplanes

• SDN controller

An architecture designed with SDN in mind

What is Segment Routing?


Architecture & Technical Concepts: Intelligent SDN

Controller


WAN Limitations Impact Traffic Optimization

Service Providers

adopting new

approaches

Provider Constraints What’s Needed

Too Many

Manual Steps

Fragmented

View of the WAN

Lack of Visibility

for Troubleshooting

WAN Lacks

Real-Time Agility

Multivendor

Orchestration

Unified WAN

View for Scenario

Analysis

Network Visibility

Over Time: Past,

Present, and Future

Automation at Scale


WAN Automation EngineDelivering Optimization and Automation

Modeling

What if/predictive analysis

Global optimization

Assess historical and

real-time data

Find and manage hot

spots

Network efficiency

analysis

Programmatic network

control

Extensible,

open data models

Real-time traffic balancing

Intelligent bandwidth

scheduling

Automated service

delivery

Predictive Model Time Series VisibilityModel-Based Control

and Configuration

Optimization and

Automation

+ + =WAE

Cycle


SDN Strategy for SPs – High-Level View

Model driven, end-to-end service lifecycle and

customer experience focus

Seamless integration with existing and future

OSS/BSS environment

Loosely-coupled and modular architecture

using open APIs and standard protocols

Orchestration across multiple domains and

layers provides centralized policy and services

across the entire network

BSS

OSS (Fulfillment and Assurance)

Service-Intent API

SDN / APIs

Orchestration, Service, and Policy Implementation

Branch, CPE

Control

Multi-layer

WAN SDN

Data Center

and NFV

Control

EMS, NMS

Netconf,

YANGCLI,

SNMPBGP

Segment

RoutingPCEP Openflow

Openstack,

vCenter

Multi-Vendor End-to-End Management and Orchestration(Physical and Virtual)

CPE Metro and Access WAN Data Centre

WAE


…

WAN Automation Software Suite

WAN Automation Engine

Collector Deployer Network Interface

Current Model New ModelNetwork Modeler

Service, Network, and

Analytics REST APIs

SNMP CLI NetFlow BGP-LS NMS/EMS NC/YANG OSC PCEP

Analytics CalendaringOptimization and Prediction

Segment

Routing

Optimizer

Bandwidth on

DemandBandwidth

Calendaring

Offline

PlanningIGP

Convergence

Analyzer

Failure

Analysis

InventoryWeather

Map

Coordinated

Maintenance

Application

Latency

Routing

Unified Application Framework


WAE Includes Cisco’s Version of ODL


Cisco® Open SDN Controller

Segment

Routing

Optimizer

Bandwidth on

DemandBandwidth

Calendaring

Offline

PlanningIGP

Convergence

Analyzer

Failure

Analysis

InventoryWeather

Map

Coordinated

MaintenanceApplication

Latency

Routing

Unified Application Framework


WAN Automation Applications

Offline Planning, Design, and

Analysis

Online Visualization, Analytics, and

Business Intelligence

Managed Resource Inventory,

Security, and Maintenance

Optimized Bandwidth Placement Extensible Application Integration Automated Tunnel Creation and

Traffic Load Management

Inventory Maintenance

Window

Scheduler

Network

ACL

Manager

Offline

Planning

IGP

Convergence

Analyzer

Failure

Analysis

Weather MapBGP Route

Visualizer

Business

Intelligence

Bandwidth

Calendaring

Bandwidth on

Demand

Tunnel

SplitterTunnel

Builder

Tunnel

BalancerApplication

Latency Routing

Segment Routing

Optimizer


WAE Strategic Initiatives

Segment Routing

NSO (Tail-F) WAE Integration Unified Multilayer

WAE Applications

Coordinated maintenance, bandwidth calendaringBuilt for SDN | Foundation for application-engineered routing

applications that will have the ability to direct network behavior

Data Centre A

Traffic-aware intelligent programmability of multi-vendor networksGlobal network view | Optimization across layers

Future: Add OTN to activation, planning, and optimization

Data Centre B


Use Cases & Implementation: Purpose

Built Applications


• Guaranteed Link/Node FRR in any topology

• 50-msec protection

• Simplicity

• Entirely automated

• No directed LDP session

• No RSVP-TE tunnels

• Incremental deployment

• Applicable to LDP primary traffic

• Optimal backup path along postconvergence path

• Prevents transient congestion and suboptimal routing

TI-LFA: Automated 50-msec Protection for IGP Segments


WAE Design – TILFA Simulation

• How many segments in backup chain

• Capacity analysis during FRR transient state


IPv4 MPLS Transport with FRR

• IPv4 over MPLS: the obvious way it should have been done

• Just the IGP to operate

• Sub-50-msec FRR integrated and automated

• Seamless migration

• SR/LDP interworking

A B

M N

PE2PE1

All VPN services ride on the prefix segment to PE2

Any service resolving on IGP IPv4 Prefix SID

Internet

VPNv4

6PE

PW


IPv6 MPLS Transport with FRR

• IPv6: the opportunity to do it right from the start

• Just the IGP to operate

• Sub-50-msec FRR integrated and automated

A B

M N

PE2PE1

Internet/v6 rides on the Prefix segment to PE2

Any service resolving on IGP IPv6 Prefix SID

Internet v6

VPNv6


MPLS Data-Plane Monitoring

B C

N O

A

9101

9105

9107

9104

9101

9105

9107

9108

9104

9105

Nanog57, Feb 2013

91089105

9108

9102

9108

9102

draft-geib-spring-oam-usecase-02

OAM


Disjoint TE Service

• A to Z any plane

• IGP shortest-path

• Prefix SID of Z (65)

• A to Z via blue plane

• SRTE policy pushes one additional segment “Blue Anycast” (111)

• Benefits

• ECMP

• No hop-by-hop signaling load and delay

• No midpoint state

16065

pkt

16065

pkt

16111


Latency TE Service

• Data from Tokyo to Brussels

• IGP shortest-path via US, higher and cheaper capacity

• Prefix SID of Brussels

• Voice from Tokyo to Brussels

• SRTE policy pushes one additional segment “Russia Anycast”

• Low-latency path

• Benefits

• ECMP

• Availability of the anycast segment against node failure

• No hop-by-hop signaling load and delay

• No mid-point state

Node segment to Brussels

Node segment to Russia

Brussels

pkt

Data

Brussels

pkt

Russia

Voice


AS1

AS2

AS3

Content Producer Engineers its WAN Traffic to Egress Peers

AS4

B

C

D

E

Payload

9.9.9.9/32

Payload

PeeringSID(E)

PrefixSID (C)

Engineered Path

TE Policyinstalled by Controller

Payload

PrefixSID(B) Payload

Best BGP and IGP

Path

Payload

PeeringSID(E)

Engineered Path

ISIS/SR-based WAN

A


SR-Based MSDC

• MPLS data-plane

• BGP control-plane

• No LDP, No RSVP-TE

• Integrated/Automated FRR

• No hop-by-hop manual configuration of static routes and their FRR behaviors

• Global label for easier operation

• Same SRGB at each switch

• SR-TE WAN Optimization Controller applicable to DC fabric


AS1

AS2

AS3

Distributed DC for Content Engineering to Local Peers

AS4

B

C

D

E

Payload

9.9.9.9/32

Payload

PeeringSID(E)

PrefixSID (C)

Engineered Path

TE Policyinstalled by Controller

Payload

PrefixSID(B) Payload

Best BGP Path

Payload

PeeringSID(E)

Engineered Path

BGP/SR-based DC Fabric


End-to-End Policy from DC, through WAN to Peer

vPEF

App

App

ToR Leaf Spine DCE BRLSR

BR

BR

Classify

flow and

push SR

segment

list

SR DC SR WAN

Top Segment

provides ECMP-

path to selected

DCI

Next segments

implement

WAN Policy:

Cost vs Latency

Disjointness

Select egress BR

Last segment

selects egress

peer



ToR Leaf Spine DCE BRLSR

BR

BR

SR DC SR WAN

Illustrated end-to-end policy implemented by the application:

• Two service hops in the DC

• Low-latency path in the WAN

• Engineered peering exit to Internet consumer



ToR BRLSR

BR

BR

Classify

flow and

encode ACI

policy

ACI DC SR WAN

ACI fabric

swicthes to

selected border

switch

ACI policy is mapped into

segment list to implement

the flow-based WAN policy:

Cost vs latency

Disjointness

DCE


Large-Scale Aggregation

• Only IGP/SR (no BGP)

• Automated FRR including ASBR failure

• SRGB (k) << # access nodes (100k)

• SDN Controller programs the segment list together with service creation

CoreAcces1 Acces2A 70

B 72

ASBR2A 1002

ASBR2B 1002

C 72

ASBR SID’s are anycast

ASBR SID’s are unique across the entire domain

ASBR anycast prefixes and SID are redistributed within each access region

Access Nodes are provided a SID which is unique with respect to its attached ASBR’s but not necessarily unique across the whole domain

{72} leads to B within Access1{72} leads to C within Access2{1001, 72} leads to B from anywhere{1002, 72} leads to C from anywhere

ASBR1A 1001

ASBR1B 1001


Use Cases & Implementation: Purpose Built Applications for WAE


Network element

ID circuits traversing

node

Impact to global network

Network capacity to reroute

LSPs

Time changes prior to outage

Time normalization

Coordinated Maintenance

Select Evaluate Schedule


Coordinated MaintenanceWAN Automation Application


Bandwidth Calendaring

Source, destination Time Bandwidth SLA

Impact and feasibility to global

network for the calendared

event

Confirm calendared event

Connect with billing system

Generate quote

Select Evaluate Schedule

Data Center #1Data Center #2

PCEP

WAN

R1R2


Application-Engineered Routing Segment Routing: WAE Calculates Shortest Path and Programs Router A





Apps REST APls

App requests 2 Gbps from

A to ZStep 1

Shortest path ABCDZ is congested between

C and D. Path ABCOPZ is fine. WAE

verifies BW availability; steers the

traffic on this path.

Step 2

WAE instantiates

the PCEP tunnel on

A {16066, 16068,16065}

Step 3

D

M N P

Z

16065

16068

16066

Full

O

A B C

PCEP


Application-Engineered Routing Segment Routing: WAE Calculates Two Disjoint Paths and Programs Router A





Apps REST APls

App requests disjoint paths

between A and ZStep 1

WAE dynamically computes

two disjoint paths to steer

the traffic

Step 2

D

A Z

B

C

E

M ON

Two tunnels avoiding the

optical shared-fate links

WAE programs

two PCEP tunnelsStep 3

PCEP


Use-Case: Bandwidth Scheduling (On Demand)

Provider’s customer has an on-demand need for a data

center backup

Problem

After determining a best path, WAE programs an LSP

using PCEP

Result

Network conditions, content site

reachability fed to collector1

RESTful APIs

Customer requests DC #1 – DC #2

bandwidth ASAP2

Demand admission request:

<R1-R3, B/W, NOW>3

WAE returns option and customer

confirms4

3

4

If needed (insufficient bandwidth),

R1-R3 LSP tunnel programmed using

PCEP 5


PCEP

WAN

R1

R2Congested!!

R3

2

5





1


Use-Case: Bandwidth Calendaring

Enterprise customer uses self-service portal to request

bandwidth between data centers

Problem

At the predetermined time, WAE places the demand on

the network (using either IGP or MPLS TE)

Solution

Network conditions reported to collector

consistently1

RESTful APIs

Customer requests DC #1 – DC #2

bandwidth at a future date 2

Demand admission request:

<R1-R3, B/W, future date>3

WAE returns booking

confirmation as the future date nears4

3

4

On the future date, WAE places

customer demand on IGP or explicit path

(TE tunnel)5


WAN

R1

R2

R3

2

5

1





PCEP


Use-Case: Tunnel Load Balancing

A service provider needs to efficiently use expensive

resources (high-cost links, perhaps transoceanic)

Problem

The most expensive network resources are fully

optimized by WAE, assigning best load share metrics

using PCEP

Solution

Network conditions reported

to collector, accessible to app1

RESTful APIs

App determines LSP imbalance and

requests WAE to recalculate LSP load-

share metrics2

WAE computes new

load share metrics 3

WAE programs new load-share metrics

for LSPs using PCEP4

2TE Tunnel Builder

App

WAN

R1

1

AS Foo





PCEP

4

3


Use Case: Policy-Based Path Planning

A service provider needs to provision disjoint LSPs from

an access to aggregation router, even across failures

Problem

WAE creates LSPs and ensures paths remain

disjoint

Result

Network conditions reported

to collector, accessible to app1RESTful APIs

App requests disjoint LSPs from access

to aggregation router2

WAE computes new LSPs based on

current topology 3

WAE programs tunnels using PCEP 4

2TE Manager

App

The app and WAE work together to

automatically keep these paths disjoint,

despite failures or topology changes5

1





PCEP

4

5 WAN

Access Node Aggregation

Node

3


P1

PE1

P2

PE2CE1

CE2

Demo Topology

Lo0

SID 16041

Lo0

SID 16141

Lo0

SID 16142

Lo0

SID 16042

10

100

10

10

10

10

10

10

5

1005

30

5

20

Under normal conditions MPLS labels propagated via SR ISIS extensions,

traffic CE1-CE2 travels over LSP following IGP best path

IGP metric = RED

TE metric = BLUE

16042

IP

IPIP

IP

POP (PHP)


Conclusion


Segment

Routing

(SW upgrade)

SDN

Controller

Applications1

Applications express

requirements – bandwidth,

latency, interactive …

2The controller collects data from the

network – topology, link states, link

utilization, …

3

Applications are mapped to a path defined

by a list of segments

Network maintains segments only

No application state

The SolutionApplication Engineered Routing


Additional References & Information

• Cisco.com Page for Application Engineered Routing

• http://www.cisco.com/c/en/us/solutions/service-provider/application-engineered-routing/index.html

• Segment Routing Page

• http://www.segment-routing.net/

• Cisco.com Page for WAE Products and Associated Services

• http://www.cisco.com/go/networkmodeling

• WAE on DevNet

• https://developer.cisco.com/site/wae/

• Cisco WAN Segment Routing Demo – Realizing your WAN/MAN Orchestration Dreams

• https://www.sdxcentral.com/resources/sdn-demofriday/segment-routing-cisco-demofriday/

• Cisco Advanced Services Capabilities and Offers

• Just Ask!

http://www.cisco.com/c/en/us/solutions/service-provider/application-engineered-routing/index.html

http://www.segment-routing.net/

http://www.cisco.com/go/networkmodeling

https://developer.cisco.com/site/wae/

https://www.sdxcentral.com/resources/sdn-demofriday/segment-routing-cisco-demofriday/

Thank you.