www.mpls2012.com

The Impact of SDN On MPLS Networks

Adrian FarrelJuniper Networks

afarrel@juniper.net

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

3

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

4

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?

Questions?

afarrel@juniper.net

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