IIR London

K. ArvindLondon, September 28, 2000

Service Intelligence for Optical Networks

Top 50 Companies to Watch


Internetworking IP Routing and Optical Switching to Build

The Next Generation Intelligent Optical Network

Examining theProgress Being Made by

Standards GroupsK. Arvind

Founding Engineer

[email protected]


Plan of the Presentation“Make no little plans; they have no magic to stir men's blood”, D. H. Burnham

• IP/O Internetworking Evolution

• IP/O Internetworking Standards – Why, Who, What

• IP/O Control Plane Standards

• IP/O UNI Standards

• Conclusion


IP/Optical Internetworking Evolution

• Evolution of carrier network architecture

• Today

• Tomorrow


Current Generation “Technology is like fish. The longer it stays in the market, the less desirable it becomes”, Andrew Heller, IBM

• SONET 1980s

• IP Tsunami 1990s

• Multi-layer Architecture

• SONET core

• DWDM for capacity

• ATM for intelligence


What is wrong? “Every solution breeds new problems”, Murphy’s Law

• SONET provisioning: static, fixed sizes

• SONET+DWDM is expensive

• Fat data pipes: Need SONET multiplexing?

• ATM: OC-3 (predominant), OC-12

• ATM: Complex

• Rack space at POPs and COs


Next Generation

• Two Layers• Transport Layer

– Bulk Transport

• Service Layer– Service

Intelligence– Bandwidth =>

Revenue


Transport Layer: Bulk Transport


Service Layer: Service Intelligence


Next Generation: Topology View


IP/O Internetworking Standards

• Why?

• Who?

• What?


IP/O Standards: Why?

• Industry: Interoperability vital for success

• Carriers: Best of breed product selection

• Vendors: Faster time to market and revenue


IP/O Standards: Who?“The nice thing about standards is that there are so many to choose from”, A.S. Tannenbaum

• IETF

• ODSI

• OIF

• ANSI T1/X1.5

• ITU


IP/O Standards: What?

• Control Plane– Signaling, Routing,

Protection, Management

• Optical Service Layer– IETF (MPLS/Traffic

Engineering)

• Optical Transport Layer– IETF (MPλS)

• Inter-Layer Control– ODSI, OIF, IETF (O-UNI)



• Optical Service LayerOptical Service Layer– IETF (MPLS/Traffic IETF (MPLS/Traffic

Engineering)Engineering)

• Optical Transport Layer– IETF (MPλS)

• Inter-Layer InterfaceInter-Layer Interface– ODSI, OIF, IETF (O-UNI)ODSI, OIF, IETF (O-UNI)


Transport Layer Control“Who controls the past controls the future. Who controls the present controls the past”, George Orwell

• IP/MPLS-based control plane– robust, scalable, well-understood, interoperable, field-tested

• Paradigm: MPλS

• Frame-work: IP over Optical

• Routing Protocols

• Signaling Protocols

• Link Management


MPλS

• draft-awduche-mpls-te-optical-02.txt

• Isomorphism between layers– Dynamic provisioning and maintenance of virtual pipes– Virtual pipe = Segments (FEC,λ) stitched together at

cross-connects (LSR, OXC).• Label switching at both layers

• Dynamic provisioning: – Path selection: Automated selection of pipe segments

• Topology discovery (routing protocols), Algorithmic constraint-based routing

– Signaling: Coordinated configuration of cross-connects


IP over Optical Framework

• draft-many-ip-optical-framework-01.txt

• UNI + Optical Transport Layer

• Interconnection Models: Peer and Overlay

• Intra and inter-optical subnet issues:– Addressing, Neighbor discovery, Topology

discovery, Restoration models, Signaling issues


Optical Routing Protocols

• draft-komplella-mpls-optical-00.txt

• IS-IS/OSPF extensions

• New TLVs to advertise characteristics specific to optical links.

• Link type TLV, Path sub-TLV, Link Media Type TLV, SRLG TLV

• Link bundling considerations


Optical Signaling Protocols

• draft-saha-rsvp-optical-signaling-00.txt• draft-komplella-mpls-optical-00.txt• draft-ashwood-generalized-mpls-signaling-00.txt

• Atomic bi-directional LSP setup• Reduce trail establishment latency• Support for permanent light paths• Fast notification of failures• Generalized label request and label


Optical Link Management

• draft-lang-mpls-lmp-01.txt

• Link Management Protocol (LMP)• Bundled link: 1 control + n x data channels• Control channel diverse from data channels• IP encoded• Functions:

– Control channel management– Link connectivity verification– Link property correlation– Fault isolation


Transport Layer Control: Review

• Paradigm: MPλS • Frame-work: IP over Optical • Routing Protocols • Signaling Protocols • Link Management



• Optical Service LayerOptical Service Layer– IETF (MPLS/Traffic IETF (MPLS/Traffic

Engineering)Engineering)

• Optical Transport LayerOptical Transport Layer– IETF (MPIETF (MPλS)λS)

• Inter-Layer Interface– ODSI, OIF, IETF (O-UNI)


Inter-Layer Control

• Inter-Layer Control Coupling Models

• Optical UNI Signaling– Messages– Protocols– Architecture


Control Coupling Models“People can have the Model T in any color - so long as it's black” - Henry Ford

• draft-ip-optical-framework-01.txt

• Overlay Model (Domain Services Model)– Uncoupled: ~ IP over ATM– Loosely coupled: ~ IP inter-domain routing

• Peer Model (Unified Service Model)– Tightly Coupled: Control planes collapsed

into one


Collapsed Control Planes


Overlay Model

• Independent routing domains• Reachability Information

– Loosely coupled: BGP, OSPF/ISIS– Uncoupled: Address registration protocols

• Independent signaling/traffic engineering• UNI signaling: ODSI, OIF• Non-IP service layer: SONET, ATM• Separate administrative domains


Peer Model

• Integrated routing domain• Complete visibility: One big IP network• Unified traffic engineering/signaling• UNI signaling not required

– draft-ashwood-generalized-mpls-signaling-00.txt

• Data overlay• Both layers are IP-based• Single administrative domain


Which Model?“Comparisons are odorous”, III,v,15, Much Ado About Nothing

• Peer or overlay?• Deployment and interoperability time frame

– Peer , Overlay

• Legacy infrastructure reuse– Peer , Overlay

• Non-IP service layer– Peer , Overlay

• Power and elegance– Peer , Overlay

• Short Term => Overlay, Long Term => Peer


Optical UNI

• Actions

• Messages and TLVs

• Signaling Entities

• Control channels

• Interactions

• Protocols

• Management


Optical UNI: Actions

• Signaling:– Set up, Tear down, Modify light paths– Light path status enquiry– Light path Event Notification

• “Inter-Domain Routing”– Address registration and de-registration

• Service Discovery


Optical UNI: Messages

• draft-bala-mpls-optical-uni-signaling-00.txt

• Lightpath Create Request/Response• Lightpath Delete Request/Response• Lightpath Modify Request/Response• Lightpath Status Enquiry/Response• Lightpath Notification• ODSI/OIF/IETF closely aligned


Optical UNI: TLVs


• Identification-Related Parameters– Light path end points: IP address + logical port– Contract ID: identifies service contract– Light path ID: unique within optical network– User Group ID: RFC 2685 VPN ID– UNI-C ID: IP address of client device


Optical UNI: TLVs


• Service-Related Parameters:– Directionality: Unidirectional or bidirectional– Framing: Signal format (PDH/SONET/SDH etc.)– Bandwidth: Service bandwidth – Transparency: PLR-C, STE-C, LTE-C– Propagation delay: milliseconds– Service level: priority, preemption, QoS


Optical UNI: TLVs


• Routing-Related Parameters– Diversity: List of the following

• Light paths with which resources should not be shared• Type of diversity: node, link, or SRLG diverse

• Security-Related Parameters– To be specified; reuse security parameters of

signaling transport where possible.

• Policy/Accounting/Authorization-Related– To be specified


Optical UNI: Signaling Entities“Traffic signals in New York are just rough guidelines”, David Letterman

• Head End Client (Initiating UNI-C, Trail Head)– IP, ATM, SONET

• Tail End Client (Terminating UNI-C, Trail Tail)

• Third Party Client: ODSI• Head End OXC (Initiating UNI-N)• Tail End OXC (Terminating UNI-N)• Optical Network Controller (ONC)

• Logical or Physical Entity


Optical UNI: Signaling Entities


Optical UNI: Control Channels

• In-Band – Overhead bytes (e.g., SONET Line DCC)– Digital wrapper overhead channel– Signaling, Service Registration

• Out-of-Band– e.g., Ethernet– Signaling only


Optical UNI Control Channels


Optical UNI: Interactions

• Who talks to whom and when?– OIF: Traditional UNI ordering

• Head end router, Head end OXC, Tail end OXC, Tail End Router and back

– ODSI: Flexible ordering• Service layer devices Optical Network

Controller– Control Route TLV– Service layer coordination prior to UNI request– Single point of interaction

• Third party signaling


Optical UNI: Protocols

• Service Discovery– ODSI: PPP extensions (ODSICP)– OIF: Under development

• Address Registration– ODSI: PPP extensions (ODSICP)– OIF: Neighbor discovery

• Signaling: OIF/IETF, ODSI


OIF UNI Signaling Protocol

• OIF/IETF: CR-LDP extensions– draft-aboulmagd-mpls-ldp-optical-uni-00.txt

• Reliable transport for TLVs between router and OXC.

• Create: Label Request, Label Mapping• Modify: draft-ietf-mpls-crlsp-modify-01.txt

• Delete: Label Release, Label Withdraw

• Notification

• New LDP messages: Status enquiry, Status response


OIF UNI Signaling Protocol

• OIF/IETF: RSVP-TE extensions– draft-gray-mpls-rsvp-oif-uni-ext-00.txt

• Maps RSVP objects and procedures for UNI• Create: Path, Resv• Modify: LSP setup procedures

• Delete: PathTear, ResvTear (Reliable)• Notification• RSVP Diagnostics (RFC2745): DREQ (Status

enquiry), DREP (Status response)


ODSI Signaling Protocol

• ODSI: – UNI is not MPLS– Clients may be SONET, ATM devices

• RSVP/CR-LDP excess baggage?

– Simple protocol sufficient for TLV transport– TCP-based application– Signaling request Build up and

Unwinding of distributed transaction.


Optical UNI Management

• ODSI MIB, OIF UNI MIB

• Simple

• Monitoring only

• No support for setting up light paths via SNMP.


Status and Future Direction“If it were done when 'tis done, then 'twere well it were done quickly”, Macbeth Act I

• ODSI: November time frame• OIF: End of the year• IETF: IP over Optical SIG• Convergence between standards efforts• Long Term Evolution towards Unified Control• Future Work

– Interconnection of optical subnetworks– Dynamic cut through routing


Conclusion"I stand by all the misstatements that I've made.” Dan Quayle

• Summary:– Evolution, Why, Who, What

• Tremendous interest and momentum– Interoperability– IP-centric standards

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