ª Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000 IP Over Optical IP Over Optical Nasir Ghani Nasir Ghani , Ph.D. , Ph.D. Industry Program Chair, OPTICOMM 2000 Industry Program Chair, OPTICOMM 2000 [email protected][email protected]ghanin ghanin@yahoo.com @yahoo.com Tutorial presented at OPTICOMM 2000, Dallas, TX, October 2000 Tutorial presented at OPTICOMM 2000, Dallas, TX, October 2000
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Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
IP Over OpticalIP Over Optical
Nasir GhaniNasir Ghani, Ph.D., Ph.D.
Industry Program Chair, OPTICOMM 2000Industry Program Chair, OPTICOMM 2000
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
Traditional ApproachesTraditional Approaches
z Largely based upon existing TDM (SONET) infrastructuresØ Point-to-point DWDM links interconnecting routers:
Multiple inter-router links (one per wavelength)
Ø Rely on SONET control/provisioning (“IP-ATM-SONET-DWDM”)Ø Multiple layers to provide required service functions:
IP: application connectivity/routing, some traffic engineeringATM: “traffic engineering” (slow, mainly PVC based)SONET: transport and protection switchingWDM layer: pure transport capacity expansion
z “Packet-Over-SONET” (POS) is a well-known representationØ IP packets framed in HDLC and mapped to SONET frames:
Details of mapping in IETF RFC 1619
Ø SONET provides transport and protection functionality
Ø IP protocols for service provisioning, traffic control
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
Traditional ApproachesTraditional Approaches
IP-SONET-WDM via Packet Over SONET (POS)
Wavelength laser transponders
DemuxMux
Wideband receivers
Gigabit IP Router
IP routing protocols (OSPF, BGP)
IP/PPP/HDLC packet mappings to SONET frames (OC-48, OC-192)
Gigabit IP Router
SO
NE
T
SO
NE
T
Point-to-point DWDM links (linear or ring
SONET topologies)
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
Traditional ApproachesTraditional Approaches
z Huge scalability concerns for large traffic volumesØ The “glass-ceiling” effect, limits of electronic processing:
E.g., IP or ATM buffering/classification/scheduling
Ø Increased equipment costs, plant space requirementsØ Cannot keep pace with full, multi-wavelength line rates:
z Many higher-layer networking applicationsØ Improved, flexible connectivity: lightpaths ≈ “virtual” linksØ Multi-protocol/service: “transparency” for IP, ATM, GbE, etc.
Ø Reduced layering: less equipment/maintenance costs
Ø Improved survivability: obviates need for rigid TDM overlays
Software signaling interface: address registration, lightpath actions (setup, takedown, modify), policy control, etc. Software entities residing at border IP routers and border optical network elements
Possibly also “IP-like” distributed signaling for lightpath action requests inside optical domain
Endpoint reachability (addresses, VPON ID’s),
service discovery
UNI
Possibly NMS control (i.e., centralized resource/policy control)
Multiple client types (e.g., non-IP) supported, such as ATM switches, SONET/SDH network elements, Escon nodes, etc.
Border OXC
Border OXC
Core OXC
Modified IP-MPLS protocols or proprietary signaling/routing
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
z Overall featuresØ All nodes run common routing protocols, maintain same state
Ø Optical nodes assigned IP addresses, i.e., IP router peersØ Single instance of distributed routing, “flat network” hierarchy:
Ø Both IP and optical layers use “same” (IGP) routing protocol:I.e., different instances (versions): routing, databases
Ø Domain-specific extensions to protocols:E.g., free/available channels, link diversity, analog metrics, etc.
Ø Adapt inter-domain protocols for end-point reachability exchangePreclude source routing of (optical) lightpaths by packet LSRs
Ø Border routers “leak” IP addresses (e.g., external BGP):Can further filter/limit prefixes to same user-groups/VPON’s
z Benefits and advantagesØ Good step in migration to full “data-centric” optical networksØ Can employ quickly, fast re-use of IP-based protocols
Ø Highly amenable to the MPλS framework
Network Models: Integrated ModelNetwork Models: Integrated Model
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
z Network-to-network interface (NNI) requirementsØ Automated interface between optical domains (in/out of band)
I.e., border OXC’s resolved across domains (wrt IP dest.)Ø Similar control actions as UNI (request, release, modify, query)
Ø IP addresses must be unique across domains
z Current NNI proposals (further standardization required)Ø Border gateway protocol (integrated) or MPOA/NHRP (overlay)
Ø BGP for inter-domain IP address exchange:E-BGP: advertises IP address prefixes between border OXCsI-BGP: advertises IP address prefixes to other border OXCs
Ø Can also use OSPF hierarchy for inter-domain exchange:Two-level, define “area border OXCs” and summary LSAs
Ø Multi-domain service survivability/recovery:Intra-domain between ingress/egress OXC’sInter-domain end-to-end recovery (NNI signaling)
Network Models: NNI ConcernsNetwork Models: NNI Concerns
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
Border router
Inter-Domain Interworking
Optical domain A
Border λSR
Optical domain B
Border λSR
Optical domain C
Border λSR
Border router
UNI
UNI
NNI
NNINNI
Intra-domain protection
Inter-domain protection
Signaling between border router-border optical network element for partial (aggregated) end-point information, e.g., integrated model
Signaling between border optical network elements (lightpath request, release, protection, etc.)
Possibly E-BGP or two-level OSPF for inter-domain end-point exchange
Modified IGP (e.g., OSPF) propagating optical network topology and resource updates inside a domain
Network Models: NNI ConcernsNetwork Models: NNI Concerns
I-BGP for end-point information propagation between border OXC’s in a given domain
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
z International Telecommunications Union (ITU-T)Ø Define complete architecture, optical transport network (OTN)
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
Network Models: ODSINetwork Models: ODSI
Trail Head
Optical Network Controller (ONC)
Trail Requester
User devices (e.g., IP routers, ATM switches, SONET/SDH cross-connects, Gigabit Ethernet nodes, etc.) source ODSI bandwidth action requests and comprise trail requester, head, and tail nodes
ODSI control messages (TCP/IP transport)
ODSI bandwidth (trail) action messages (create, destroy, modify, query). Request actions relayed to ONC via head and tail entities
ONC responses to trail requester’s bandwidth actions (e.g., trail acknowledge, trail notification), sent back to trail requester entity.
Trail Tail
ONC validates request action and allocates capacity for bandwidth, resides inside optical network (e.g., co-located with optical networking device such as OXC/WRS, O-ADM).
Point-to-point bandwidth connection (data)
Sample ODSI Interaction
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
OutlineOutline
zzz IntroductionIntroductionIntroduction
zzz Traditional ApproachesTraditional ApproachesTraditional Approaches
Ø Extensions required for optical link, node representations:Link type: transparent/translucent, media type, etc Link bundling: scalable abstraction for large “link” countsWavelength usages: active, allocated, pre-emptable, reservedSwitching capabilities: static/“any-to-any”, λ-conversion, etc.Shared risk link group (SRLG): route diversity informationUpdate triggers: thresholds to control signaling loads
Ø Added requirements for “all-optical” nodes (w/o λ-conversion):Per-link analog metrics (e.g., dispersion, distance, etc.)Per-channel usage (routing scalability concerns)
Ø Further extensions for survivability:Protection setup information (path/span, shared/dedicated, etc.)Fast fault notification/switchover signaling messages
z Constraint-based routing (CBR)/policy controlØ Application driver for signaling protocols (little standardization):
Use information from opaque LSA database, policy rules
Ø “Optical” resource control (e.g., traffic engineering)Lightpath routing (RWA) algorithms, “virtual topology” control
Ø Re-use COPS protocol for policy control functions:Client/server-based (centralized policy server)
Ø Multiple levels of wavelength sharing, improved efficiency:Dedicated and shared protection wavelengths (≈1:1, M:N)
Ø Recovery timescales increase w. hop counts
Ø Translucent monitoring for sub-path switching?
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
Service SurvivabilityService Survivability
Ring Topology Mesh Topology
DC
A BFailed channel sub-
path (near-side) ring switch
(i.e., A-B-D)
Failed channel path (far-side)
ring switch(i.e., A-C-D)
A
B
D
C
Failed channel path switch(i.e., A-B-E)
E
F
Failed channel sub-path switch(i.e., A-B-D-E)
DC
A BAll wavelengths span switched
(i.e., A-B-D for red, B-D for green)
A
B
D
CAll wavelengths span
switched (i.e., A-C-D-E)
E
Multi-fiber diversity
F
PathSwitching
SpanSwitching
Working:A-B-D (red)
Working:A-C-D-E (red)
Working:A-B-D (blue)B-D (red)
Working:A-C-D-E (red)
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
z Integration with MPλλS frameworkØ Possibly extend MPLS LSP protection to cover lightpaths:
Optical (electronic) monitoring but MPLS performs switchovers
Ø Generic protection switch/merge nodes (PSL/PML) definedØ New MPLS messages/priorities:
Fault indication signal (FIS), PSL/PML identification, etc.
Ø Fast routing reverse notification tree (RNT) (less routing delays)
Ø Possibly new specialized protocols emerging
z RWA implications for lightpath protectionØ “Joint-RWA” of working, protection lightpaths at setup timeØ Protection channels must be hop and SRLG-disjoint:
I.e., Constrained to exclude all working-path fibers, nodes
Ø “All-optical” RWA restricts further (no λ-conversion)Ø Compute complexities, can use graph-pruning:
Possibly use a fast route server (centralized)?
Service SurvivabilityService Survivability
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
Dedicated 1:1 Protection
Working connection (solid)
Dedicated protection wavelengths (dotted)
Shared Protection
Shared protection wavelength on link
A-E (dotted)
Working connection (solid)
Service SurvivabilityService Survivability
Example: Dedicated and Shared Wavelength Protection
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
ConclusionsConclusions
z New provisioning paradigms for optical networksØ TDM multi-layered models slow, unscalable, inefficient
Ø Wavelength switching timescales will decreaseWeeks ⇒ days ⇒ hrs ⇒ min ⇒ sec ⇒ ms ⇒ ns (?)
z Overlay approachesØ Optical UNI, “de-couple” IP and optical signaling control
Ø Standardization efforts maturing, good transitional approach
z Peering and integrated approachesØ Expand IP-based provisioning/control plane frameworkØ Most direct integration, flat and hierarchical solutions
z MPλλS solutionØ Powerful framework, lends faster interoperability
Ø Routing, signaling, traffic engineering, survivability, etc.
Ø Amenable to many future evolutions
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
ReferencesReferences
z N. Ghani, et al, “On IP Over WDM Integration,” IEEE Communications Magazine, March 2000.z B. Rajagoplan, D. Pendarakis, D. Saha, S. Ramamurthy, “IP Over Optical Networks: Architectural
Aspects,” IEEE Communications Magazine, September 2000.z N.Chandhok, et al, “IP Over Optical Networks,” IETF Draft, draft-osu-ipo-mpls-issues-00.txt, July
2000..z J. Luciani, et al, “IP Over Optical Networks-A Framework,” IETF Draft, draft-ip-optical-framework-
00.txt, February 2000.z D. Awduche, et al, “Multi-Protocol Lambda Switching: Combining MPLS Traffic Engineering Control
With Optical Crossconnects,” IETF Draft, draft-awduche-mpls-te-optical-01.txt, November 1999.z N. Ghani, “Lambda-Labeling: A Framework for IP Over WDM Using MPLS,” Optical Networks
Magazine, April 2000.z L. Ceuppens, “Multiprotocol Lambda Switching Comes Together,” Lightwave Magazine, Aug. 2000.z O. Aboul-Magd, et al, “Signaling Requirements at the Optical UNI,” IETF Draft, draft-bala-mpls-
optical-uni-signaling-00.txt, July 2000.z J. Hahm, K. Lee, M. Carson, “Control Mechanisms for Traffic Engineering in Optical Networks,” IETF
Draft, draft-hahm-te-optical-00.txt, July 2000.z D. Pendarakis, B. Rajagopalan, D. Saha, “Routing Information Exchange in Optical Networks,” IETF
Draft, draft-prs-optical-routing-00.txt, March 2000.z P. Ashwood,et al,“Generalized MPLS-Signaling Functional Description,” IETF Draft, draft-ashwood-
generalized-mpls-signaling-00.txt, August 2000.z K. Kompella, et al, “Extensions to IS-IS/OSPF and RSVP in Support of MPL(ambda)S,” IETF Draft,
draft-kompella-mpls-optical-00.txt, August 2000.z J. Lang, et al, “Link Management Protocol (LMP),” Internet Draft, draft-lang-mpls-lmp-01.txt, July
2000.
Nasir Ghani, Ph.D. , Industry Program Chair, OPTICOMM 2000, Dallas, TX, October 2000
ReferencesReferences
z N. Ghani, “Survivability Provisioning in Optical MPLS Networks,” 5th European Conference on Networks and Optical Communications, Stuttgart, Germany, June 2000.
z L. Ceuppens, et al, “Performance Monitoring in Photonic Networks in Support of MPL(ambda)S,”IETF Draft, draft-ceuppens-mpls-optical-00.txt, September 2000.
z L. McAdams, J. Yates “Lightpath Attributes and Related Service Definitions,” IETF Draft, draft-mcadams-lightpath-attributes-00.txt, September 2000.
z N. Ghani, et al, “COPS Usage for ODSI,” IETF Draft, draft-ghani-cops-odsi-00.txt, July 2000.z K. Liu, C. Liu, J. Wei, “Overlay versus Integrated Traffic Engineering for IP/WDM Networks,” IEEE
Globecom 2000, San Francisco, CA.z International Telecommunication Union (ITU-T), Architecture of Optical Transport Networks,
Recommendation G.872, Feb. 1999.z H. Zang, J. Jue, B. Mukherjee, “Review of Routing and Wavelength Assignment Approaches for
Wavelength-Routed Optical WDM Networks”, Optical Networks Magazine, January 2000.z S. Chaudhuri, et al, “Control of Lightpaths in an Optical Network,” IETF Draft, draft-chaudhuri-ip-
olxc-control-00.txt, Feb. 2000.z S. Verma, H. Chaskar, R. Rayadurgam, “Optical Burst Switching: A Viable Solution for the Terabit IP
Backbone,” IEEE Network Magazine, November/December 2000.z D. Hunter, I. Andonovic, “Approaches to Optical Internet Packet Switching,” IEEE Communications