IPOP2009, Tokyo, Japan Old Dog Consulting Network Virtualisation for Packet Optical Networks Adrian Farrel, Old Dog Consulting Steve West, Cyan Optics

iPOP2009, Tokyo, JapanOld Dog Consulting

Network Virtualisation for Packet Optical Networks

Adrian Farrel, Old Dog Consulting

Steve West, Cyan Optics

Daniel King, Old Dog Consulting

2iPOP2009, Tokyo, Japan Old Dog Consulting

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


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


• 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)

Overlay Networks

DWDMRouter A

Router B

Router C Router C

Router BRouter A

Physical View Logical View


Network Topology

• 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

Core Mesh

Data XC

Video Hub

AggregationSite

Long HaulXC

Distribution Sites

Spurs

Distribution Sites

Distribution RingDistribution

Ring

Distribution Ring

Distribution Ring

Distribution Ring

Distribution Ring

Distribution Ring

Spurs

Long HaulXC

Data XC

AggregationSite

AggregationSite

AggregationSite

AggregationSite

AggregationSite

AggregationSite

AggregationSite

AggregationSite


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

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


Partial Mesh Topologies

DWDM

Advantages of partial mesh network• Reduced cost

• Reduced number of transport resources• Lower nodal degree at edges

• Fits better with sparse lower layer 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

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


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


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?


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


The Packet Optical Transport Platform

XC

XC

Packet Router

• 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?

Client Interfaces


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


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


Placement of Grooming Function

• 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

A

B

C

D

A

D

C

B


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.


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

Sonet/SDH

Sonet/SDH


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


Questions ?

Feel free to send us questions

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Documents

IPOP2009, Tokyo, Japan Old Dog Consulting Network Virtualisation for Packet Optical Networks Adrian Farrel, Old Dog Consulting Steve West, Cyan Optics