The document discusses the concept of a hierarchical network controller that can abstract and provide control over complex multi-domain, multi-vendor SDN transport networks. A hierarchical network controller sits above domain-specific SDN controllers and provides an end-to-end view of the network, combining capabilities from different network domains like IP, optical, and others. This allows domain controllers to focus on domain-specific functions while the hierarchical controller provides cross-domain intelligence and optimization for end-to-end services across technology and vendor boundaries. The document also presents a case study of Vodafone using such a hierarchical approach to manage its European transport network.

1. Hierarchical Network
Controller
Abstracting Complex Multi-Domain, Multi-Vendor SDN Transport
Shahnaz Mohammad Zaki
Cisco Systems Malaysia
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2. What we will explore in the next 30 minutes:
2
SDN Deployment Review
Landscape of the Modern SP Network
SDN Deployment Scenarios
The Concept of the Hierarchical
Network Controller
Case Study
2023 MYNOG-10 HCO

3. 3
2023 MYNOG-10 HCO
Manage network scale and maximize infrastructure
investment across all network paths
The outlook of an ever-growing
size and complexity of transport
network infrastructure drives the
idea of a more autonomous and
intelligent control capabilities
The SDN
Ambition
Improve operations efficiencies and make use of analytical
data to facilitate informed decision making
Foster new service experience to create market attraction
and retain subscriber loyalty
Faster fault detection and service remediation
Continuous network optimization based on class of service

4. 4
2023 MYNOG-10 HCO
Manage network scale and maximize infrastructure
investment across all network paths
The outlook of an ever-growing
size and complexity of transport
network infrastructure drives the
idea of a more autonomous and
intelligent control capabilities
The SDN
Ambition
Improve operations efficiencies and make use of analytical
data to facilitate informed decision making
Foster new service experience to create market attraction
and retain subscriber loyalty
Faster fault detection and service remediation
Continuous network optimization based on class of service
“Cut cost, make more money”

5. The Need for Automation
2023 MYNOG-10 HCO
The Larger the
Scale, the Higher
the Demand
5
This Photo by Unknown Author is licensed under CC BY-SA-NC

6. 6
Landscape of a Modern SP Network
Network domains which may varied by locations and vendors
NodeB
Etnerprise
Broadband
NodeB
Etnerprise
Broadband
Internet & Cloud
Network Assurance & Control Across each Domains
2023 MYNOG-10 HCO
service flows across multiple network domains

7. The Challenge: Rigid & Fragmented Networks
• Transport networks are a patchwork of
technologies, domains, layers and vendor
turfs
• Most still rely on a siloed, highly manual and
error-prone operational apparatus
• Current network data is fiendishly difficult to
collect, corelate and utilize
IP Aggregation NW
IP Core Network
Metro Optical Vendor A
LH Optical Vendor B
Delivering SDN automation use cases are
bounded by network domains and
achieving end-to-end service can be very
limited

8. Transport SDN
Deployment Scenarios
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2023 MYNOG-10 HCO

9. Vendor Independent Platform
What we always hoped to be
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Transport SDN Vision
Provisioning Configuration Optimization
Assurance AI / ML
Telemetry
Vendor A Vendor B Vendor C
IP Core IP Metro DWDM Region 1
Planning
SNMP SSH BGP-
LS
PCEP TL1 Netconf /
Restconf
gNMI
OSS BSS
API API
Vendor D
DWDM Region 2
A single platform-independent solution that provides
multiple integrated SDN functions which works across
all network domains and OSS/BSS layer
2023 MYNOG-10 HCO
Service creation, bandwidth on demand, service
optimization, service prioritization, close-loop,
predictive analysis...
Common Seen Challenges
• Device Scale limits to support large networks
• Advance SDN network optimization capabilities are
vendor centric - not proprietary but exclusively
developed
• Multi-vendor integration is not mature enough
• Standards are not fully adopted
• Software lifecycle nightmare – one component
upgrades can cause incompatibility chain effect
• SP adoption of DevOps / NetOps

10. Vendor A
Incumbent Vendor SDN Deployment
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Transport SDN Scenario 1
Provisioning Configuration Optimization
Assurance AI / ML
Telemetry
Vendor A Vendor B
IP Core IP Metro DWDM Region 1
Planning
SNMP SSH BGP-
LS
PCEP Netconf /
Restconf
gNMI
OSS BSS
API API
Most common transport SDN deployment seen in the market
where incumbent vendor for the network takes the lead in
deploying SDN. Produces well tested use cases and less
complicated. Commonly for smaller SP.
2023 MYNOG-10 HCO
The challenge
• Advance capabilities are vendor-domain specific, with
close tie-ins between software and hardware pre-sets
• Potential vendor lock-in and onboarding of third-party
innovation within domain is a challenge if not
impossible
• No failure correlation between domains – example:
optical-to-IP
Vendor B
Configuration
Assurance
Planning
TL1
SNMP
DWDM Region 1
Provisioning

11. Domain-specific deployment
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Transport SDN Scenario 2
2023 MYNOG-10 HCO
The challenge
• Siloed topology awareness between domains
• No failure correlation between domains – example: optical-
to-IP
• Network optimization is domain specific and different from
another
• Cross-domain service optimization is limited as network data
are not exchanged
• SP needs to maintain API for every domain vendors and
OSS/BSS
SDN capabilities which are vendor-specific IP and
optical domains, by combining all the management and
control components needed for unified, closed-loop and
self-sufficient operations of that domain. Each domains
can offer best of capabilities are within vendor specific
elements. Commonly for large SP.
Vendor D
Vendor B
DWDM Region 2
Vendor D
Vendor B
IP Metro Region 2
Vendor A
Provisioning
Configuration
Optimization
Assurance
AI / ML
Telemetry
IP Core IP Metro Region 1 DWDM Region 1
Planning
OSS BSS
Vendor B
Configuration
Optimization
Assurance
AI / ML
Telemetry
Vendor C
Configuration
Optimization
Assurance
Planning
Planning
AI / ML
TL1
SNMP SSH BGP-
LS
PCEP
Netconf /
Restconf
gNMI SNMP SSH
API API API

12. The Hierarchical Network Controller
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Transport SDN Scenario 3
2023 MYNOG-10 HCO
The challenge
• Domain-level SDN deployment as first step
• Validation of domain-level northbound interface
capabilities
• Potential manual correlation mapping between infra
layers
The hierarchical network controller together with the
multi-vendor domain SDN controllers introduces a
hierarchical SDN controller architecture providing an
end-to-end view (both horizontal and vertical) of the
transport network combining the IP/MPLS, optical
domains or other domains and providing an abstracted
network view of the higher-layer OSS systems.
Vendor D
Vendor B
DWDM Region 2
Vendor D
Vendor B
IP Metro Region 2
Vendor A
Provisioning
Configuration
Optimization
Assurance
AI / ML
Telemetry
IP Core IP Metro Region 1 DWDM Region 1
Planning
OSS BSS
Vendor B
Configuration
Optimization
Assurance
AI / ML
Telemetry
Vendor C
Configuration
Optimization
Assurance
Planning
Planning
AI / ML
TL1
SNMP SSH BGP-
LS
PCEP Netconf /
Restconf
gNMI SNMP SSH
API API
Hierarchical Network Controller
TL1
SNMP Netconf /
Restconf

13. The Concept
Hierarchical Network Controller
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2023 MYNOG-10 HCO

14. Hierarchical Network Controller in the
Overall SP SDN Architecture
Service Orchestrators, Assurance, Inventory, RCA…
NFV
Orchestrators
Hierarchical Network Controller
Access
Controller
SDN controllers
Optical Controllers SDN controllers
SDN controllers EMS / Controllers
Microwave WDM/OTN IP/MPLS/Ethernet Data Centers
Mobile/Fixed/CPE
2023 MYNOG-10 HCO

15. IP Network
15
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• Multi-layer visualization and mapping (Fiber-Optical-IP) allows
domain managers to maintain and correlate link assets
• Acquire each domain-specific network data and normalize into
common network model to provide and end-to-end view as
well as multi-layer view
• Domain controllers focus on domain-specific optimization and
assurance, while Hierarchical Controller provides inter-domain
intelligence for end-to-end serices
• Abstracts and simplifies SP’s OSS transformation, as
hierarchical network controller becomes a common point of
interface to execute network wide use-cases
The Concept Advantage
Hierarchical Network Controller
VPN Services
Fiber
Fiber
Leased Fiber
Optical
Network
Vendor C
Metro Vendor D
NLD
Vendor B
Metro
Vendor B
Metro
Vendor A
IP Core Vendor C
Aggregation
Vendor 1 Vendor 2
Optical
Vendor A
IP Domain Controller
IP
Open SDN
Architecture
Hierarchical Network Controller

16. Recommended Capabilities
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Hierarchical Network Controller
REST APIs for inventory, topology and service CRUD
OSS BSS
Database / Query Language
Map integration / visualization
Network Inventory
Path Computation
IETF Based Interfaces – NETCONF, RESTCONF
Legacy Support– TL1, SNMP
Network
• Open northbound interfaces – REST API
• Soutbound interfaces – towards domain managers and
controllers
• IETF-based (NETCONF)
• ONF Supported – T-API
• Legacy southbound interface support – SNMP and TL1
(DWDM)
• Strong database engine and open query language – SQL
• Path computation engine (PCE Server component)
ONF Supported – T-API
2023 MYNOG-10 HCO

17. 17
Key recommended features of the hierarchical SDN controller
Feature Description
Modularity The platform should be flexible enough to allow plug and play and swapping of modules at varying
levels of granularity depending on the service provider’s need, for example, the PCE or management
applications (assurance and planning).
Openness It should open northbound and southbound interfaces/APIs with minimal integration effort. Large
ecosystem support with open APIs, SDKs and a developer community would provide additional
value.
Standards and model-
based
Support for industry standard data modelling languages, protocols, and APIs such as those from
MEF, TMF, IETF and ONF as well as compatibility with legacy SNMP/CLI- based operations.
Extensibility/gradual
deployment
Service providers need a flexible and adaptable software solution to enable them to incrementally
cover additional services and domains over time. This will also require legacy/backwards
compatibility with existing infrastructure.
Cloud-native platform
architecture
Built using a set of common and shared micro-services/functions to enable rapid onboarding of new
features and functions to meet future requirements. It should also support various deployment
models including on-prem and cloud-hosted and provided in a software-as-a-service (SaaS)
licensing model.
Source: Analysys Mason
2023 MYNOG-10 HCO

18. Case Study
Vodafone Europe
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2023 MYNOG-10 HCO
This Photo by Unknown Author is licensed under CC BY-NC-ND

19. Vodafone
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• Linking more than 270 third-
party and Vodafone-owned
data centers across Europe
and Africa
• Up to 250 terabytes of data
traffic at any one time
• Integration with Juniper Paragon
Pathfinder, Ciena MCP controller,
Huawei NCE-T and Cisco CNC
• Network for mobile, fixed data and
voice traffic to serve hundreds of
millions of users and third-party
internet and content providers in 28
countries across four continents
Global Transport Network
“This enables end-to-end multilayer automation and
programmability, removing the complexity for third party
services interacting with the network.”
Alessandra Pavese
Head of Cloud and Connectivity Evolution and Automation, Vodafone

20. • Supporting HA scenarios of a failure during provisioning and
discovery scenarios
• L0L1L2 services
• PWLSPTE++
• L2L3 VPN
• Topology visualization of all domains and of all
layers from OTS to LSP
• Discovery using scheduled polling cycles and
notifications for near real time updates
• Device HW inventory
Shelves
Cards
Pluggable ports
• Uses applications set for advanced assurance and
analytics
Vodafone Main Use Cases
Provisioning
Topology Visualization
Service Assurance and Analytics
HA
Inventory
2023 MYNOG-10 HCO

21. IP
Service
Optical
Fiber
The Hierarchical Controller Network
Model – from service to fiber
Initial Use Cases: Service to Fiber Visibility
Layered service view in
Hierarchical Controller UI
Visualization of a protected private line service
– zoom out and zoom in views
2023 MYNOG-10 HCO

22. Understand all network layers
Understand physical risks
+
Risk Management
• What will be the impact of taking down a set of
resources for maintenance?
• Is the network vulnerable to 1 or 2 failures?
• What would be the impact of a failure?
• Define diversity policies for any set of connections
and see if they are violated
Understand service mapping to network

23. Target Architecture

24. Key Takeaways
• Allow domain-level to perform best-of-breed
while..
• Having cross-domain intelligence and produce
end-to-end service outcomes
• Take IP + Optical integration as first wins
• Feasibility studies required, may not be for
everybody
2023 MYNOG-10 HCO

25. Thank You
25
2023 MYNOG-10 HCO