A Unified Control Plane
Dream or Pipedream?
Adrian Farrel
Old Dog Consulting
IETF Routing Area Director
Old Dog Consulting
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
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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
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OSPF and IS-IS
RSVP-TE and CR-LDP
LMP and Nortel’s own offering
Lessons from history
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We do not need multiple solutions for the same problem
Development cost is more than doubled
• Who pays?
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Interoperability is compromised
• Providers are “locked in”
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Deployment is complicated
• Additional or more expensive operations teams
• Company mergers, etc. become a nightmare
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“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 both
And be one traveller…
Robert Frost (The Road Not Taken – 1915)
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The IETF made decisions
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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?
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The equipment was available
The providers were looking at deployment
But?
There are a number of roadblocks
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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
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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
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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
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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 crossconnects
• 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
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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
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Questions
adrian@olddog.co.uk
adrian.farrel@huawei.com
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