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1) OpenFlow: One of a number of possible SDN approaches 2) SDN: Empowers the operator with reduced OPEX and CAPEX 3) PCE: Solves some real-world carrier problems
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Pat Moore
PCE, OpenFlow, & the Centralized
Control Plane
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Software Defined Networking (SDN)
Key elements of SDN are Intelligence moves from NEs to control cloud Physical separation of control plane / data plane
OSS/BSS Smart Control Cloud
SDN
Network Equipment
Traditional
Dumb Network
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What Does SDN Offer?
Empowering the operator Reduced OPEX
Simplify operation by more powerful abstraction of the network Optimize resource usage through centralized data and algorithms Simplify process for upgrading network software
Reduced CAPEX Cloud offers better price / performance for CPU power
New possibilities Specific per-operator traffic optimizations More dynamic network topologies Network virtualization
Facilitate innovation Up till now this has been the domain of the NE vendor
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OpenFlow – One Form of SDN
Standard control/data plane interface Stanford / Open Networking Foundation
OpenFlow v1.2 recently finalized Inter-operable
Offers considerable flexibility OpenFlow paradigm is complex
So cloud software tools to abstract it are critical
Smart Control Cloud
OpenFlow formalizes this interface For each received packet
• Match fields in packet header • Perform specified action
Dumb Network
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OpenFlow Applications
Began life in the research community Prototyping new networking schemes Evolving for more general deployment
OpenFlow paradigm has wide applicability Operators and carriers Data centres Organizations with unique networking requirements Ethernet, IP (and maybe MPLS)
It requires new software tools OpenFlow constructs are too low level for users Success fundamentally depends on these tools
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Path Computation Elements – also SDN
Define a “route-query” interface IETF standard for PCE protocol (“PCEP”)
RFCs 4655 5088 5089 5394 5440 5441 5520 5521 5541 5557 6007 Architecture RFCs 6 years old, Specification RFCs 3 years old
Simple network paradigm “How should this (G)MPLS traffic flow be routed?” NEs query the cloud (opposite way round from OpenFlow)
Path Computation
Elements PCE also formalizes this interface NEs operate much as today
• Signaling function resides on NEs • Routing function resides in cloud
Semi-smart Network
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PCE for Inter-Area TE Routing
PCE server can be in the cloud Provides CPU power for potentially massive TE database Operator can interact with it
And therefore influence routing policy
NEs retain signaling intelligence The nuts and bolts that make the network function
Area A Area B
Ingress LER Egress LER
PCE Server
LSP
Client/server Route Query
TE Routing Updates
See this live at the EANTC Interop Event!
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More Advanced PCE Capabilities
Multiple PCE servers can used Keeps carrier’s internal topology private
Domain A sees only an encrypted key to Domain B path Key carried in signaling and expanded once in Domain B
Auto-discovery of PCE servers Redundant PCE servers
Domain A Domain B
Ingress LER Egress LER
PCE Server (domain A)
PCE Server (domain B)
LSP
Inter-domain route query
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PCE for WDM/OTN
Routing is a major user of CPU power Same colour needed end-to-end
Full RWA algorithm can require huge processing power NEs may have restricted connectivity
Connectivity matrix adds routing complexity Optical impairments
PCE offers a way forward Lower cost CPU capacity for complex algorithms Simpler software upgrades as the algorithms evolve Carriers visibility into routing decisions
And crucially control the routing policy or algorithm
PCE can be integrated / co-located with OSS
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PCE for Multi-Layer Networking
PCE server triggers auto-provisioning tool Delay LSP setup Provision an extra wavelength When ready, tells ingress LER to use it
Tool can include operator provisioning rules
Ingress LER Egress LER
PCE Server
Client/server Route Query
TE Routing Updates
Out of capacity
Cloud softwareauto-provisioning tool
Add another lambdaAnd use it when ready
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Key Take-Aways OpenFlow
One of a number of possible SDN approaches Getting lots of attention, but still early days Revolutionary and disruptive Likely first applications
Ethernet and IP Networking “Islands” e.g. data centres
PCE Solves some real-world carrier problems Well established IETF standards Evolutionary Likely first applications
Transport networks e.g. WDM, OTN, MPLS-TP
See PCE at the EANTC stand
