1. Central Office Re-architected as
a Datacenter (CORD)
Presenter: Zhen-Yuan Bo
Date: November 25, 2015
Course: ECE1548 – Advanced Network Architecure

2. Traditional Telecom Central
Office
² What does it look like?

3. Traditional Telecom Central
Office
² What are the downsides of such Central Office?
n Large number of complex facilities
n Difficult to introduce new services
n Huge cost of CAPEX/OPEX incurred
² How to minimize the negative effects of these
downsides?
n Virtualization Comes Into Play!!!

4. Traditional Telecom Central
Office
² Technological Revolution –Virtualization
² CORD = SDN X NFV X Cloud

5. CORD = SDN X NFV X Cloud
² Work hand in hand to create a cloud-style and
economic architecture
² VNFs run either inVMs or in WhiteBox Switches
Examples: Fire Wall, URL
Filtering, Parental
Control

6. CORD – Hardware Architecture
² Consists of commodity servers and switches
² An open ONOS-controlled leaf-spine fabric
interconnects all components
² Benefit:
n Many OLT devices in a Central Office can be
virtualized
n Saves a significant amount of CAPEX and OPEX
cost

7. CORD – H.W. LAYOUT

8. CORD – Software Architecture
² Three open source software platforms (Control)
n ONOS, OpenStack, XOS
² Functionality of each platform
ONOS Manage underlying switching fabric
Host many control applications
Open Stack Creating and ProvisioningVMs and
VNs
XOS Unify infrastructure services, control
plane services, and any data plane or
cloud services

9. CORD – S.W. LAYOUT

10. Legacy Central Office
² Three legacy network devices
n Optical Line Termination (OLT)
n Customer Premises Equipment (CPE)
n Broadband Network Gateway (BNG)
² As a result of Virtualization…
n All refactored as software running on commodity
servers, white-box switches and merchant silicon
I/O blades

11. Legacy Devices - CPE
² What is CPE?
n Any terminal located at a subscriber’s premises
and is connected with a carrier’s telecom channel
n Examples:

12. Legacy Devices - BNG
² What is BNG?
n Access point for subscribers, allow them to
connect to the broadband network
n The subscriber can access the broadband services
provided by the Network Services Provider or
Internet Service Provider when connection is set
up.

13. Legacy Devices - OLT
² What is OLT?
n It is a device that serves as the service provider
endpoint of a passive optical network.
n Example:

14. Services Provided By vOLT,
vCPE, vBNG
² Access-as-a-Service (ACCaaS)
n Implemented by vOLT, where each tenant
corresponds to a SubscriberVLAN.
² Subscriber-as-a-Service (SUBaas)
n Implemented by vCPE, where each tenant
corresponds to a Subscriber Bundle.
² Internet-as-a-Serivce (INTaaS)
n Implemented by vBNG, where each tenant
corresponds to a Routable Subnet.

15. Service Composition Details

16. Summary
² Virtualization of Traditional Central Office
n Hardware Components: Commodity Servers
n Software Platforms: OpenStack, ONOs, XOS
n Benefit: scalable services, economic in costs