Download Network Virtualisation for Packet Optical Networks

Network Virtualisation for
Packet Optical Networks
Adrian Farrel, Old Dog Consulting
Steve West, Cyan Optics
Daniel King, Old Dog Consulting
iPOP2009, Tokyo, Japan
Old Dog Consulting
Agenda
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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
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Commercial Objectives
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Offer a wide range of client services and connectivity
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Leverage maximum revenue from transport networks
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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
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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)
Use a single management point to operate multiple layers
Provide consolidated multi-layer network visualization
Dynamically (and independently) reconfigure network layers
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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
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Overlay Networks
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Networks constructed from equipment switching a single technology
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Network resources may be partitioned to support different customers or applications
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IP/MPLS, Ethernet, TDM, OTN, DWDM
Internet Backhaul, Video Distribution, Wireless Operator, Customer VPN, and service classes
Client-Server network relationships
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Client networks links provided by connections in a server layer
Client and server networks are independent
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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)
Physical View
Router C
Logical View
Router A
DWDM
Router B
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Router C
Router A
Router B
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Network Topology
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Spurs
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.
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Mesh Networks
Distribution Sites
Distribution
Ring
– Networks are made up of different
topological constructs including spurs,
rings, hub and spoke, partial mesh, and
full mesh
• 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
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Aggregation
Site
Distribution
Ring
Aggregation
Site
Spurs
• Spurs and rings are deployed in
sparse transport networks, mesh in the
core
Distribution
Sites
Distribution
Ring
Aggregation
Site
Data
XC
Data
XC
Long
Haul
XC
Aggregation
Site
Distribution
Ring
Aggregation
Site
Long
Haul
XC
Core Mesh
Aggregation
Site
Aggregation
Site
Aggregation
Site
Distribution
Ring
Distribution
Ring
Aggregation
Site
Video
Hub
Distribution
Ring
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Full Mesh Topologies
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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
Advantages of full mesh network
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Direct, any-to-any connectivity
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Minimize delay in provisioning new client
services
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Server layer treated as a set of logical links
• No worries about client connectivity
• Simplified client network management
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Redundant connections in case of failure
iPOP2009, Tokyo, Japan
Disadvantages of full mesh network
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Waste of transport resources
• Under-use of dedicated resources
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n2 scaling issues
• Complexity of server layer planning
and management
• Edge nodes need more server layer
resources (line cards, lasers, etc.)
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Abstraction Trap: Client has no idea of
physical path
• Cost of client services is high
• Protection may not be real
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Partial Mesh Topologies
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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
Advantages of partial mesh network
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Reduced cost
• Reduced number of transport resources
• Lower nodal degree at edges
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Fits better with sparse lower layer topologies
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Disadvantages of partial mesh network
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Reduced CAPEX offset by increased planning
and operational costs
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Network planning more sensitive to demand
matrix
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Network operation requires traffic engineering
• Avoid link congestion
• Guarantee resource sharing
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Data paths are more complex
• Paths may become long
• Protection harder to guarantee
• Routers may become congestion points
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Network Aggregation
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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
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High degree of edge-to-edge connectivity
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More efficient use of core resources
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Share server resources among multiple client
overlay networks
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Bulk data forwarding/switching at lower layer
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Model may be reproduced at multiple
technology layers
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Edge equipment cheaper and simpler
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DWDM
Disadvantages of aggregation
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Aggregation points must perform routing
• MPLS tunneling can reduce complexity
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Additional equipment cost and complexity at
aggregation points
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Complex to plan and optimize
• Traffic demand changes can break the
model
• Protection and resiliency may be harder
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Regrooming
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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
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Simplify the core mesh
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Make even better use of core resources
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Retain high degree of edge-to-edge
connectivity
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Continue to perform bulk data
forwarding/switching at lower layer
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Model may be reproduced at multiple
technology layers
Disadvantages of regrooming
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Need more sophisticated (expensive) nodes
within the core
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Positioning of regrooming nodes is a
headache
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Network planning and operation significantly
complex
• Need dynamic software assistance?
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Packet Optical Networks
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Objectives
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Deploy “packet optical nodes”
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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
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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.
Capable of switching, aggregation, and regrooming at multiple layers
• E.g.: packet, TDM, and WDM
Utilize sophisticated planning and management tools
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Placement of equipment within the network
Generation of virtual networks
Dynamic changes to aggregation and grooming policies
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The Packet Optical Transport Platform
Client Interfaces
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Fundamental component of future
networks
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Each node is capable of playing a role in
multiple network layers
Potential for pluggable line cards, switchfabrics, adaptation modules, and
grooming
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Strategically placed within the network to
perform aggregation and regrooming
Means that planning is less rigid
Truck-roll flexibility does not require forklift upgrades
Packet Router
XC
Increased flexibility makes planning
potentially very complex
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Key issues…
• What equipment to put at each site?
• How to plan the virtual network at
each layer?
• How to aggregate and groom traffic?
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XC
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Network Virtualization and Visualization
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Graphical Display Tools
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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-youget environment improves
confidence and reduces
operator errors
In-service experimentation
to help plan changes
What-if scenario trials
Sophisticated tools already
available
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Network Planning
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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
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Placement of Grooming Function
B
D
A
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Old network requires 14 lambda hops
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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
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A
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Network Planning: Virtual Network Topology
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Dynamic traffic engineering and path computation components
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Virtualization of network resources
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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
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Distributed TE Routing in each layer
Path Computation Element (PCE)
Virtual Network Topology Management (VNTM)
Multiple server networks may provide transport trunks to multiple clients
Network reoptimization
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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.
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Multiple clients
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A scalable and flexible packet optical infrastructure supports multiple client networks
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Lambda service layer
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Layer 1 VPN
10G Lambda
Sonet/SDH
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Native Ethernet
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TDM
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IP / MPLS
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VLAN Services
Sonet/SDH
Sonet/SDH
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Summary
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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
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Cost-effective network operation
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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
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Questions?
Feel free to send us questions
[email protected]
[email protected]
[email protected]
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