1. Network Virtualisation for Packet Optical Networks
Adrian Farrel, Old Dog Consulting
Steve West, Cyan Optics
Daniel King, Old Dog Consulting
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2. Agenda Commercial Objectives Overlay Networks Mesh Topologies
Network Aggregation and Regrooming
Packet Optical Networks
The Packet Optical Transport Platform
Network Planning
Placement of network function
Supporting Multi-client Networks
Summary

3. Commercial Objectives
Offer a wide range of client services and connectivity
Carry legacy and packet services
Support wholesale services (more than 50% of traffic for some operators)
Allow rapid provisioning of new customer services
Support changing traffic demands
Allow addition of new customer sites
Enable rapid protection at lower layers (closer to the fault)
Leverage maximum revenue from transport networks
Don’t waste optical bandwidth
Don’t provision expensive equipment that isn’t needed (just-in-time deployment)
Get scaling benefits from switching traffic at lower layers
Integrate and simplify operations and management of multiple technologies
Use a single management point to operate multiple layers
Provide consolidated multi-layer network visualization
Dynamically (and independently) reconfigure network layers
Change the way client connectivity is provided
Reoptimise the transport network
Invisible to client network
Change the connectivity in the client network
Add new links between client nodes

4. Overlay Networks Physical View Logical View
Networks constructed from equipment switching a single technology
IP/MPLS, Ethernet, TDM, OTN, DWDM
Network resources may be partitioned to support different customers or applications
Internet Backhaul, Video Distribution, Wireless Operator, Customer VPN, and service classes
Client-Server network relationships
Client networks links provided by connections in a server layer
Client and server networks are independent
Client has no visibility or control of server layer resources
Server layer is payload agnostic
A server may support multiple clients (possibly using common resources)
A client may use connectivity from multiple servers
In this example we use an optical network (server layer) to create interconnections between
routers for packet network services (client layer)
DWDM
Router A
Router B
Router C
Physical View
Logical View

5. Network Topology Layered Networks Mesh Networks
Core Mesh
Data XC
Video Hub
Aggregation Site
Long Haul XC
Distribution Sites
Spurs
Distribution Sites
Distribution Ring
Layered Networks
Each layer has its own topology
The topology of the physical network is defined by the available physical resources
Higher layers have virtual links that tunnel through server layers.
Mesh Networks
Networks are made up of different topological constructs including spurs, rings, hub and spoke, partial mesh, and full mesh
Spurs and rings are deployed in sparse transport networks, mesh in the core
All topological constructs can be represented using a mesh
The mesh is most sparse at the edge, and more fully meshed in the core
Topology is often more fully meshed in the higher layers, and more sparse at the lower layers

6. Full Mesh Topologies
Packet routers are connected by a full mesh of packet-layer links
Packet-layer links are realised by dedicated paths through the optical core
DWDM
Disadvantages of full mesh network
Waste of transport resources
Under-use of dedicated resources
n2 scaling issues
Complexity of server layer planning and management
Edge nodes need more server layer resources (line cards, lasers, etc.)
Abstraction Trap: Client has no idea of physical path
Cost of client services is high
Protection may not be real
Advantages of full mesh network
Direct, any-to-any connectivity
Minimize delay in provisioning new client services
Server layer treated as a set of logical links
No worries about client connectivity
Simplified client network management
Redundant connections in case of failure

7. Partial Mesh Topologies
Packet routers are connected by a partial mesh of packet-layer links
Packet-layer links are realised by dedicated paths through the optical core
Packet delivery may require routing at intermediate routers
DWDM
Disadvantages of partial mesh network
Reduced CAPEX offset by increased planning and operational costs
Network planning more sensitive to demand matrix
Network operation requires traffic engineering
Avoid link congestion
Guarantee resource sharing
Data paths are more complex
Paths may become long
Protection harder to guarantee
Routers may become congestion points
Advantages of partial mesh network
Reduced cost
Reduced number of transport resources
Lower nodal degree at edges
Fits better with sparse lower layer topologies

8. Network Aggregation
DWDM
Traffic from multiple sources is collected together
Aggregated traffic is for the same set of destinations
Edges are attached as spurs
Connectivity in core network is a simpler mesh
Advantages of aggregation
High degree of edge-to-edge connectivity
More efficient use of core resources
Share server resources among multiple client overlay networks
Bulk data forwarding/switching at lower layer
Model may be reproduced at multiple technology layers
Edge equipment cheaper and simpler
Disadvantages of aggregation
Aggregation points must perform routing
MPLS tunneling can reduce complexity
Additional equipment cost and complexity at aggregation points
Complex to plan and optimize
Traffic demand changes can break the model
Protection and resiliency may be harder

9. Regrooming
Some nodes within the core network capable of performing routing
Allows traffic to be moved from one trunk to another
Traffic can also be switched at the server layer (default behavior)
Advantages of regrooming
Simplify the core mesh
Make even better use of core resources
Retain high degree of edge-to-edge connectivity
Continue to perform bulk data forwarding/switching at lower layer
Model may be reproduced at multiple technology layers
Disadvantages of regrooming
Need more sophisticated (expensive) nodes within the core
Positioning of regrooming nodes is a headache
Network planning and operation significantly complex
Need dynamic software assistance? 9

10. Packet Optical Networks
Objectives
Satisfy the commercial objectives
Carry packet traffic over an optical core
Integrate packet and optical networks
Achieve all of the benefits of the mesh, aggregation, and regrooming techniques
Minimize the disadvantages!
Harmonized NMS, OSS, etc.
Deploy “packet optical nodes”
Capable of packet and optical function
Switching of optical circuits
Termination of optical circuits for local delivery and for packet processing
Routing, aggregation, and grooming of packets
Deployed in an optical mesh
Used to build a virtual packet network
Use multi-layer nodes
Capable of switching, aggregation, and regrooming at multiple layers
E.g.: packet, TDM, and WDM
Utilize sophisticated planning and management tools
Placement of equipment within the network
Generation of virtual networks
Dynamic changes to aggregation and grooming policies

11. The Packet Optical Transport Platform
Client Interfaces
Fundamental component of future networks
Strategically placed within the network to perform aggregation and regrooming
Each node is capable of playing a role in multiple network layers
Potential for pluggable line cards, switch-fabrics, adaptation modules, and grooming
Means that planning is less rigid
Truck-roll flexibility does not require fork-lift upgrades
Increased flexibility makes planning potentially very complex
Key issues…
What equipment to put at each site?
How to plan the virtual network at each layer?
How to aggregate and groom traffic?
Packet Router XC XC

12. Network Virtualization and Visualization
Graphical Display Tools
Enhance operator understanding by clearly displaying subsets of links
Concurrently display data for multiple network layers
Show dependencies and resource allocations across layers
What-you-see-is-what-you-get environment improves confidence and reduces operator errors
In-service experimentation to help plan changes
What-if scenario trials
Sophisticated tools already available

13. Network Planning
Network planning is a multi-layer optimization process
Demands need to be determined at each layer
Network links at one layer are demands at the next layer
Planning dictates
Logical topology at each layer
Physical topology at the lowest layers
Placement of grooming and aggregation function
Networks are designed using off-line planning tools:
Select equipment, fibre, and bandwidth based on:
Projected traffic growth.
Service levels (availability, service delivery times)
Total network cost (capital and operating costs)
Online network planning
Determine when to add, modify, and remove logical links
Plan and reserve capacity for shared and path-disjoint protection
Trigger just-in-time deployment of network hardware
Deployment of cards, cross-connects, and adaptation functions

14. Placement of Grooming FunctionB D A C
Old network requires 14 lambda hops
Full mesh of connectivity between routers
Insertion of regrooming function (at D) reduces this to 7 lambda hops
If traffic load A-to-B grows, a separate lambda can be used and can be switched at D D B A C

15. Network Planning: Virtual Network Topology
Dynamic traffic engineering and path computation components
Distributed TE Routing in each layer
Path Computation Element (PCE)
Virtual Network Topology Management (VNTM)
Virtualization of network resources
Virtual Network Topology (VNT) is a tool for service and transport aggregation
Better utilize available resources to support more client layers and services
VNT supports inter-layer network engineering
The virtual network topology can be tuned based on client demands
Multiple server networks may provide transport trunks to multiple clients
Network reoptimization
Significant savings may be possible if resource allocations are occasionally reoptimized
Changes must be subject to policy or operator supervision
Virtual link flapping is to be avoided as it would flap lower layer resources
Reoptimization includes both intra-layer (traffic engineering) and inter-layer (virtual topology)
Intra-layer reoptimization will be required more often
The rate of reoptimization should be significantly lower at the lower network layers.

16. Multiple clients
A scalable and flexible packet optical infrastructure supports multiple client networks
Lambda service layer
Layer 1 VPN
Native Ethernet
TDM
IP / MPLS
10G Lambda
VLAN Services
Sonet/SDH

17. Summary
Commercial and operational trade-off between connectivity and aggregation
Full mesh network
Provides maximum flexibility for service delivery
Does not scale and is wasteful of expensive resources
Traffic aggregation
Can be dynamic using changing traffic demands and new service deployment
Harder to plan and needs more sophisticated equipment
Cost-effective network operation
Photonic network is the foundation for scalable bandwidth and switching flexibility
Multi-layer switching, grooming, and aggregation at strategic nodes
VNT provides a powerful tool for managing a multi-layer network
Sophisticated planning software will be required
Substantial new revenue streams from multiple client networks
Not all client networks are packet networks
Maybe “packet optical” is the wrong name!
Introducing Integrated Optical Networks

18. Feel free to send us questions