The Impact of SDN On MPLS Networks Adrian Farrel Juniper Networks afarrel@juniper
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Transcript of The Impact of SDN On MPLS Networks Adrian Farrel Juniper Networks afarrel@juniper
Agenda
• Some Definitions Needed (SDN)
• Why consider SDN?
• SDN as a toolkit
• Fine-grain programming
• An interface to routing and policy
• Enabling services
• A programmable MPLS network
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What do we mean by SDN?
• Software• It’s all software!
• We are looking for automation
• Tools or applications
• Driven or Defined• Does it matter?
• Networks• Micro-management of forwarding decisions
• Control of end-to-end paths
• Whole-sale operation of network
• Is it all about the buzz?
• Shiny-thing Desparately Needed
• $ome Dollars Now
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What will we do with SDN?
• Make our networks better
• Provide cool services at lower prices
• Reduce OPEX and simplify network operations
• Enable better monitoring and diagnostics
• Make better use of deployed resources
• Converged services are the future
• Converged infrastructure is the future
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The SDN Toolbox
• To a network, all configuration tools look like hammers• One size does not fit all• SDN is about engineering the routers to allow better tools
to be designed and applied
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MPLS Data Plane Programmability
• Label stacking, popping, and swapping• MPLS as a cross-connect technology (NHFLE)
• Prefix-to-label mapping (LFIB)
• Integration with underlying data plane• Encapsulation rules• Data link addresses
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IP Packet IP Packet
PrefixLFIBOut i/f, label
MPLS Packet MPLS Packet
In i/f, labelNHFLE
Out i/f, label In i/f, labelNHFLE
Pop
Applications and Protocols for MPLS Data Plane Programmability
• An application is software that runs remotely• That demands a protocol and a data encoding
• Element Management• IETF : SNMP/MIBs, Netconf/YANG
• Proprietary : CLI, GUI, XML
• Legacy : TL1 …
• Network Management• Coordinated connection set-up is just coordinated element management
• Control plane / data plane separation• Use an existing configuration protocol
• IETF : GSMP (RFC 3292), ForCES (RFC 5810)
• ONF : OpenFlow
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Control Plane / Data Plane Separation
• Support legacy / cheap devices
• Experiment with new routing protocols
• Integrate dynamic routing with static control
• Avoid “complexities” of routing protocols
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Data plane
Control plane
SDN Programming Language
Functional Control at a Higher Level
• Operators want to build and deploy services• “Make a pseudowire for me”• “Optimize my traffic loading”• “Provision a layer 3 VPN”• “Show me how my network is being used”• “Configure my data center”• “Manage security and policy”• “Provide service callendaring”
• Needs a higher-level interaction with the network• Demands more sophisticated control of routers• Must integrate with standard routing features
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Leveraging Existing Tools
• New services and features for rapid deployment
• There are plenty of existing tools
• Leverage implemented and deployed protocols
• We can put them together to enable high function SDN in MPLS networks
• May need some extensions
• Avoid long development cycles
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BGP-LS to Extract Topology Information
• Information about the network• Nodes and links
• Link state
• Up-to-date TE capabilities
• Delay and other quality information
• Status of existing LSPs / tunnels
• Used for network monitoring, analysis, and planning• Critical input to path computation (e.g., via PCE)
• Fundamental component unspecified in the PCE architecture
• BGP-LS is a set of simple extensions to BGP• Client is any node listening to the IGP
• For example an ASBR or a Route Reflector
• Server can not be a very light-weight BGP implementation
• Reduces dependency on IGP sniffing
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Stateful PCE for Control of Services
• Early work on PCE was stateless• PCE knows state of network• PCE does not recall anything about previous computations• PCE does not know about existing provisioned services
• Except as described on new computation requests• Stateful PCE was always in the architecture
• Retain information about provisioned LSPs• New extensions to PCEP
• Allow explicit activation of LSPs from the PCE• Receive information from network about LSPs
• Provides key components for bandwidth callendaring
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Integrating the Components
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• IGP enhanced for TE and link quality• BGP-LS reports to PCE• PCE requests LSPs• Normal LSP signaling• LSP status reports
PCE
Making New Tools
• Can’t do everything with what have already
• Interface to the Routing System (IRS)• A programmatic interface to routers
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Data Plane FIB
RIBs and RIB ManagerPolicy DB
Routing and Signaling Protocols
Topology DBOAM, Events and Measurement IRS Agent
IRS Client IRS Client
Router
Server
ApplicationApplication
Application
IRS Protocol & Data Encoding
Enabling Services
• Service enablement and turn-up is complex• Existing tools help with planning• Commissioning through scripts or work-plans
• SDN can be a set of tools to enable services• L3VPN delivery• Data center interconnect• Bandwidth callendaring• Mult-layer connectivity and virtual links
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Service Example : Multi-layer
• SDN can coordinate multiple network layers• May both be MPLS networks
• Involves many SDN components
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PCE
Traffic demandService request
VNTM
TEDB
PCE
BGP-LS
IRS
PCEP
RSVP-TE
GMPLS
IGP-TE
IRS
IRS
OpenFlow & IRS
Virtual Link
PCEP
TEDB
IRSPolicy
IGP-TE
Service Example : L3VPN with Callendaring
• Which PEs to use?• How to connect PEs?
• What load? When?• What redundancy? QoS? Security?
• How to connect to the Internet?• Planned support for high bandwidth services
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DB Replication
Content Streaming
Data Transfer
Putting the Tools into the Box
• SDN will possibly remain buzz and hype
• Or maybe it will evolve into bickering between proponents of different solutions
• Or it could become a comprehensive set of tools• Configuration tools• RIB and policy control• Topology and LSP management• Service enablement
• Potential to enable a rich set of functions in future MPLS networks
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SDN - Pandora’s Toolbox?
A mess of overlapping tools and protocols with too many features and functions?
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Or a cornucopia of riches?