old dog consulting a unified control plane dream or pipedream? adrian farrel old dog consulting ietf...
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Old Dog Consulting
A Unified Control PlaneDream or Pipedream?
Adrian Farrel
Old Dog Consulting
IETF Routing Area Director
Page 2© Copyright Old Dog Consulting 2010
Agenda• History
• Where does it all come from?
• Objectives and Dreams• Development
• Extensions and Divergence
• Success Stories• Disappointments• Why are we here?
• Why has GMPLS not taken over the world?• Why are we here in Tokyo, now?
• Where are we going?
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MPLS is Established
• MPLS is 13 years old• I have the T-shirt from MPLS2007
• All (nearly all?) major service providers have MPLS in their core networks
• The majority is LDP or L3VPN
• MPLS-TE has limited, but successful deployment
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WDM and Automation• As MPLS-TE was being developed
• Technical advances in WDM• Deployment and research of WDM systems• Management-based solutions becoming
complex
• Proposals extend MPLS-TE to provide an automated control plane for WDM systems• Multiprotocol Lambda Switching (MPλS)• draft-awduche-mpls-te-optical-00.txt
• April 2000• Awduche, Rekhter, Drake, Coltun
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Generalisation• If you can do it for packets and lambda
• Why not do it for all connection-oriented networks?• Isn’t all circuit switching the same?
• CO-PS• MPLS• ATM• Frame Relay• Ethernet
• CO-CS• Fibre• Lambda• TDM
• draft-ietf-mpls-generalized-signaling-00.txt• October 2000• Multiple ideas, many authors
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Protocol Development• MPLS-TE protocols had been
developed already• Routing• Signalling
• Generalisation of these protocols to GMPLS• Intent that GMPLS included all existing
traffic engineered MPLS
• New protocols only where new needs• LMP• PCEP
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Two Protocols for Every Use• OSPF and IS-IS• RSVP-TE and CR-LDP• LMP and Nortel’s own offering• Lessons from history
• We do not need multiple solutions for the same problem• Development cost is more than doubled
• Who pays?• Interoperability is compromised
• Providers are “locked in”• Deployment is complicated
• Additional or more expensive operations teams• Company mergers, etc. become a nightmare
• “Wrong” decisions are made• Consider regional standards that pick the “wrong” protocol
Two roads diverged in a yellow wood,And sorry I could not travel bothAnd be one traveller…
Robert Frost (The Road Not Taken – 1915)
• The IETF made decisions• Only LMP was taken into the CCAMP working group• RFC 3468 stopped work on CR-LDP• OSPF and IS-IS too well deployed to make a choice
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And Did It Work…?
• Lots and lots of implementations• This was around 2000• Everyone was building an optical switch• Most implementations were for WDM
• Significant research• Theoretical work to prove utility of control plane• Experimental equipment and networks
• A lot of successful control plane interop testing• GMPLS-enable equipments shipped
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Where are the Deployments?
• GMPLS deployments do exist• WDM deployments tend to be small
• Metro add/drop• GMPLS is a management tool• Reduces the complexity of provisioning
• Single-touch connection set-up• Network status information gathering• Intelligence remains in the NMS (not in the network)
• Some significant long-haul networks• Networks tend to be very stable• GMPLS is just a provisioning tool
• SDH networks• Many networks deployed• Some are quite large
• GMPLS has not taken over the world
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And What Didn’t Work?
• Many issues conspired to slow GMPLS• The bubble burst• TDM deployments too established
• Retro-fitting GMPLS not attractive
• No pressure to migration packet networks from MPLS-TE to GMPLS
• PBB-TE didn’t take off
• But GMPLS did fulfil its technical promise
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Why Isn’t GMPLS Widely Deployed?
• The equipment was available• The providers were looking at deployment• But?• There are a number of roadblocks
• Data plane interoperability• Equipment cost• Control channel interoperability• Control plane interoperability• Operational hurdles• Network complexity
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Roadblocks 1: Data Plane Interop
• No point in a unified control plane if the data plane doesn’t interwork
• WDM systems• Different choice of lambdas• Different power levels• Complex optical impairments• Different encodings
• TDM• SONET/SDH• Different options and features
• 2.5G, 10G, 40G encoding and modulation• Why?
• Uncoordinated development under time pressure• Regional preferences• It is not a benefit to the incumbent vendors to interoperate
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Roadblocks 2: Equipment Cost
• GMPLS is most effective in dynamic networks• Dynamic networks need flexible,
reconfigurable equipment• Flexible equipment has been expensive
• For example, in a WDM network• Best flexibility is achieved using OEO• OEO has been the most expensive equipment
• For example, control plane handling• Previous transport equipment
• Only needed lightweight CPU
• Only needed low bandwidth management channels
• Introduction of a control plane added cost
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Roadblocks 3: Control Channel Interop
• Mainly an issue in WDM systems• How to adjacent WDM nodes communicate in
the management and control planes?• In the lab we use 10/100 Ethernet
• You can’t deploy that• You could connect to an IP cloud
• Most WDM equipment has an Optical Supervisory Channel (OSC)• There are no standards for the OSC
• It is not a benefit to the incumbent vendors to interoperate
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Roadblocks 4: Control Plane Interop
• The point of standards is to achieve interoperability
• Multiple conflicting standards do not help• Why does “standards shopping” happen?
• Vendors want to add value• Competitive edge is important• Vendor-specific extensions tend to break
interoperability• They don’t need to• Why should an incumbent vendor enable interop?
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Roadblocks 5: Operational Hurdles
• Transport network operation is well established
• Transport operators are conservative• Risk-averse• Demand stability
• Huge investments already made• Extensive management systems• Education and training
• A control plane is a big hurdle
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Roadblocks 6: Network Complexity
• GMPLS is intended to simplify the network• Why do people think it makes it more complex?
• A very rich function set• Core GMPLS includes many features that are “advanced
functions” in traditional networks
• A very advanced toolkit• We are engineers – we like to build things• It is easy to apply GMPLS to some very complex problems
• Vendors need to understand and sell simplicity• Service Providers have to learn to prioritise their
requirements
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So, Why Are We Here?
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The Prospects Are Still Good!
• Plenty of other reasons to be here• Interworking between network “islands”• Continuation of the Ethernet project• Optical Transport Networks (OTN)• Advances in WDM• Green Networking• Integrated networking (IP-over-Optical)• MPLS Transport Profile
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Network Interworking• When there are vendor islands
• Still want end-to-end automation• Need “service interface” (UNI)• Need glue between networks (E-NNI)
• ITU-T ASON architecture makes these clear• MEF calls specifically for a UNI• Huge benefit in a standard protocol solution at these
interfaces• ITU-T solutions (PNNI, CR-LDP, RSVP-TE)• OIF solutions (RSVP-TE)• GMPLS
• We need a solution• We don’t need five solutions!• If GMPLS is also used at (some) I-NNI then choose GMPLS• All the RFCs exist for immediate deployment for ASON• I-Ds to support MEF UNI are about to become RFCs
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Ethernet TE is Not Dead• The scope of PBB-TE is not as large as
predicted• Campus-style deployments are still likely• Core backbone usage to link routers• Not used to build a fully-meshed core
• Network diameter and complexity is not huge• Somewhat complicated resource sharing
required• Planned reduction in forwarding table size• GMPLS offers automated and simplified
management• I-D is about to become and RFC
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OTN• G.709 is not new
• Sub-lambda technology• Recent major advances in technology
• New revision of G.709 (version 3)• Support for 1.25Gbps and 2.5Gbps• ODU-flex
• More flexible and attractive• Considerably interest in implementation and deployment
• RFC 4328• Support for G.709 version 1
• New work in CCAMP• Re-assess label format• Support all resizing and advanced features
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WDM Resurgence
• Continued increase in bandwidth demand• Introduction of lower-priced components
• PICs make OEO more affordable
• Introduction of smaller all-optical cross-connects• 2x2 and 4x4 matrices• Makes phased deployment of PXCs realistic
• ROADMs• GMPLS building blocks all in place• Next steps are impairment-aware routing
• First stages almost complete in CCAMP and PCE
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Green Networking
• A very real demand to reduce energy use
• Requirements are not limited to equipment
• It is important to route traffic to• Use most power-efficient path• Make best use of existing paths
• Increases the pressure for advanced TE• Needs to be dynamic• Needs sophisticated path computations• Most effective when integrated across layers
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Integrated IP-Optical• This is the sixth year of iPOP
• Are we wasting our time?• Maybe operators really don’t want this
• Too dynamic• Too hard to operate• Too complex to deploy
• Many attractions• Flexible equipment deployment• Flexible re-grooming• consolidated operations
• Facilitated by many innovations• High capacity, tuneable, interfaces on routers (lambda,
OTN…)• OTN flexibility• Plug-and-play integrated devices• Advanced planning software and PCE• Integrated GMPLS control plane
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MPLS-TP• Transport-grade MPLS
• OAM• Bidirectional• Protection and restoration• Optional, high-grade, TE control plane
• Work in the IETF with ITU-T cooperation• Control plane will use GMPLS• Equipment interoperability is a MUST• Questions:
• Will a control plane be used, or just management?• Will GMPLS be adopted in MPLS-TE networks?
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Where Next?• A rocky road, but…
• We have a very rich control plane toolset
• The future is in your hands• We have all of the building blocks
• New work is either very specific or very minor• We have the experimental evidence• The vendors have a marketing story• The providers see the benefits
• Get on with it!• Issue the RFQs• Build and ship the products• Deploy the networks