1. Cloudifying Central Office: Can we do it with ODL?
Sridhar K. N. Rao (Ph.D)

2. Disclaimers and Acknowledgements
It is NOT about ODL vs ONOS. NO.
Thanks to project : most of the analysis is around this project.
Thanks to sources (AT&T, Facebook (Alexey), Redhat, Ivan PepelnJacketc.,) for some images.
The opinion shared is based purely on the study and analysis of different projects and articles, and I’m not working on realizing cloudifying COs in ODL

3. Central Office A.K.A Exchange

4. What is a Central Office
Sometimes also referred as ‘Exchange’ (BSNL/MTNL)
Airtel terms it as DLC?
CO is a service provider’s “gateway” to its customers
connect customers to the rest of the network, including the Internet
great vantage point for a service provider
Facilitate in provisioning new services to customers.
A telco runs numerous COs.
There might be ~50 in Bangalore?
One CO may support around 100s of Enterprise customers and 1000s of residential/mobile subscribers.

5. Central office
Residential
Enterprise
Mobile
Central Office
(Exchange)

6. Example: Residential-GPON
Source: TE Connectivity, AT&T

7. So, why do you want to cloudify?
High CAPEX and OPEX.
Numerous proprietary Boxes, etc.
Lack of automation and customization.
Inhibits innovation, limits the ability to create new source of revenues.
 Telcos are Facing Growing Revenue Pressure From Cloud / OTT Provider.
Telcos should convince enterprises to buy their cloud services.
Reliance JIO?
Achieve the agility of a cloud-provider
OSS and Whiteboxes?
Increased flexibility – deploy new services quickly.

8. Data center networking: Ether Fabric

9. Traditional DC-Network Architecture
Leaf and Spine Fabric
[Some times Wrongly Referred as Fat Tree]
Source; Netcentric, Ivan Pepelnjak

10. Data center Fabric Clos network = multistage switching network
Very old concept (Charles Clos, 1953)
Used to build large voice switches (beyond the crossbar capability)
Clos fabrics in Data centers – High speed switching, single/multi stage, low- latency, non-blocking,

11. Spine-Leaf Network: Fabric
Source: Ivan Pepelnjak

12. Remember Facebook?
Alexey:

13. Ex. Spine and Fabric Design
Input:
Total number of Edge ports (Ex: 650)
Edge oversubscription ration (ex: 3:1)
Output:
Consider Single rack switch Configuration
48*10GE (Connected to servers)
4*40GE (Uplink – connectivity to spine)
Consider Single Spine switch configuration
32*40GE
Number of Leaf switches:
650/48 = 14
Number of leaf-to-spine links
14 * 4 = 56.
Number of Spine Switches.
56 links/32 = 2

14. Fabric Configurations
L2 Fabric
L3 Fabric
Mixed L2/L3 : L2 on leafs and l3 on spines.
With or without redundancy
Routing Protocol Choices: BGP!!!
SDN/No-SDN.
Whitebox Switches

15. Cloudifying central office

16. Cloudifying Central Office
the-central-office-will-house-the-new-telco-cloud
Virtualization and deployment of general purpose compute, storage and network capability at the local central office
Data center infrastructure satisfying Telco’s needs
On this infrastructure, deliver virtualized
Residential-CO, Mobile-CO, Enterprise-CO.

17. Virtualizing Central Office Functions
Virtual Service Gateway
Virtualizing RAN: BBU, RRU, etc.
Virtual Networks as a Service: L2VPN, L3VPN, SD-WAN Overlays
Virtual CPE
Virtualizing EPC: MME, PGW, SGW, IMS, etc.
Value Added Services: Traffic steering, Application policies, FW, WAN acceleration, Encryption
Example: GPON
OLT Termination
Managing Subscribers
SG: Subscriber Gateway
Authentication and Authorization
Event and Subscriber Information logging
Service Functions
Residential services, Self-service portal, NAT, FW, Routing, IPAM
QoS and Quota Management
Video Caching
Local Information Servers.
Mail and File Stores
Mobile Services
vBBU, C-RAN,
vBNG, vOLT
Mobile Edge Services: Caching, SoN, Billing, etc
Integrated Analytics: Observe, Analyze Control
Residential
Mobile
Enterprise
Source: ONOS

18. Cloudifying Central Office
A Cloudified Central Office is a next-generation Central Office (CO) System that incorporates SDN and NFV on top of a Software Defined Data Center architecture.
It relies on CoTS - network switches, compute nodes, etc., - for datacenter-like environment
No longer relies on the typical equipment found in CO’s. 
The compute nodes will be running virtualized network functions (VNFs) as Virtual Machines or Containers
The network switches controls traffic -
from access functions  virtualized network functions  towards the Broadband Core Network.

19. Cloudifying CO: Requirements
Datacenter Fabric.
Controlled by an SDN Controller (Typically)
VNFs – Virtualized network function.
Managed via a VNF Orchestrator/Manager
Preferably Generic?
NFVI management
VM/Containers
Openstack?
VM lifecycle management.
Service Composition
Overlay Networks
Typically achieved by SDN controller

20. Cloudifying CO: Architecture
Controller APPs: SFC, Overlay, Fabric, Switch-Configuration, Policy Management
NFV MANO Components: OpenO, OpenMano, Tacker, Cloudify, Openstack, Kubernetes, XoS,
SDN Controller

21. Virtualizing Central Office: GPON
Virtualizing an Broadband Network Gateway (BNG)
vRouter
vSG
IP funtions.
Virtualizing an Ethernet Aggregation Switch
Data center Fabric
Virtualizing an OLT
(vOLT)

22. Virtualizing Central Office: GPON
Control-Plane
Optional
Distribution-Unit
(Programmable)
OLT
H/w
Interface
vFW
vSG
vOLT
vIPS
vRouter

23. ODL for Cloudifying Central Office

24. Expectations from a SDN-Controller for Cloudifying CO*
Configure and manage Overlay Networks.
Realize Service Forwarding Graph ( Service Chaining)
Path-Implementation through NFVI.
Configuring or managing and VNFs
vRouter, SGW-Dataplane etc.
Necessary Applications (usecases support)
RAN Slicing – based on policies.
EPC core slicing (E2E – MME, SGW-C/D, PGW-C/D…)
SD-WAN
L2/L3 VPN.
Transport SDN
Analytics support
SON, Monitoring, Active Testing, Programmable Probes,
Underlay Network Configuration
Data Center Fabric.
* May not be complete 

25. RAISE YOUR HAND YES: Its all There! We are almost There.
No: We need more effort
RAISE YOUR HAND

26. Can ODL meet the Expectations?
OCP-Plugin
Network Slicing for 5G Networks:
ODL as Part of OPNFV Projects: Doctor, Promise, Multisite, HA, etc.
Expectations
YES|NO|INCOMPLETE
Configure and manage Overlays
YES
SFC
Configuring and Managing VNFs
Necessary Applications
YES*
Underlay Network Configuration
Incomplete*
Others: Time-series data repo. and centinel.
IOTDM,
Fabric as a Service
Ex Apps: traffic engineering, cloud network virtualization, L2/L3 VPNs with DC interconnectivity, SFC, network QoS, monitoring and analytics, VPP, etc.
Almost All Telcos are part of the advisory group!
*: Some of use-cases in Residential/Mobile/Enterprise Central Office can still be realized with Existing applications.

27. Trick Question: What it means to manage Fabric?
Control and Data plane separation.
Openflow?
Device Configurations
Multi-Vendor Support
L2|L3|L2/L3 Fabrics