Ip over wdm


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Ip over wdm

  1. 1. A study of “IP Over WDM” Partha Goswami 22/07/05
  2. 2. Topics• Motivations for IP over WDM• IP Traffic Over WDM• MPLS approch for IP over WDM• GMPLS Control Plane• Optical Internetworking and Signaling across Network Boundary 2
  3. 3. Motivation for IP over WDM Worldwide Network Demand 30000 •The volume of the Data traffic exceeds the 25000 20000 Voice traffic. Data Gb/s 15000 Voice 10000 5000 •Long Haul Optical network follows 0 1996 1997 1998 1999 2000 2001 2002 SONET/SDH transmission standard Year with time fame of 125 μ sec.Reference 14: Acute need to increase the data bandwidth • Most of the data traffics are due to IP traffic where existing transmission technique in the Fiber backbone is not giving Optimal Multiplexing. • Several alternative are in Consideration: •IP over Fiber • PPP to replace SONET •Lightweight SONET Reference 16: Exponential Growth of Internet 3
  4. 4. Motivation for IP over WDM Continued.. . Inflexibility in bandwidth granularity Access ringNational Ring • Each traffic source must use a fixed multiple of OC1 (51.84 Mbps) rate, for example, OC-3 (155Mbps), ADM OC-12 (622Mbps), OC-48 (2.4Gbps), and OC-192 (9.9Gbps). SDH-DWDM Metro ring High overhead • SONET frame require a minimum of PBX 3% overhead for framing, status Regional ring OLT monitoring, and management. OLT PBX • Other Protocol overhead, Here IP Over PPP over SDH How present network look like. 4
  5. 5. Motivation for IP over WDM Continued… • Advent of wavelength division multiplexing (WDM) technology that allows multiple wavelengths on a single fiber, the "IP over fiber" issue takes on a new dimension. • End stations (traffic sources) and routers (traffic switches) have a choice of wavelengths on which to direct their traffic. • High capacity of WDM and exponential growth of IP traffic is the perfect match of the need and technology Reference 15, Ch 2, Page 14 5Reference 15, Ch 1, Page 2 Thousand fold capacity enhancement for Submarine cable systemIntroduction of high capacity WDM
  6. 6. Challenges of IP over WDM• IP over WDM domain, attempts to address issues like: • Light path selection and network routing • Support for various classes of service • Algorithms for network restorations and protection scheme • Integration with existing technology • Standardization of Signaling and protocol• The future optical component technology may allow full optical switching of IP packets.• The Optical switching can be classified as follows: • Optical Circuit switching (OCS) • Optical Burst Switching (OBS) • Optical Packet Switching (OPS) 6
  7. 7. Three Generation of Digital Transport Network• First Generation: T1 , E1• Second Generation : SONET , SDH• Third Generation : Optical Transport network • Suitable for: Voice, Video, Data, QOS, BOD • Multiplexing and Switching scheme: WDM/O/O/O • Capacity: Tbps • Payload: Fixed or Variable length • Protocol support: PPP, IP, ATM, MPLS • Commercial Availability: Full feature 3rd Generation yet to arrive due to lack of mass scale commercial deployment O/O/O Reference: 1, Page 1-4 7
  8. 8. IP Traffic Over WDM network • IP Traffic Over WDM is the Correct Choice for Next Generation Internet backbone. • OCS technology is matured. • Network node will use Wavelength Routing WRS Switch and IP router. • Nodes are connected by fiber to form physical topology Wave length Routed Network • Any two IP router will be connected by all- λ1 Optical WDM Channel called light path λ1,λ2, λ3,λ4λ1,λ2, λ3,λ4 λ2 • The set of lightpath termed as Virtual topology.λ1,λ2, λ3,λ4 λ1,λ2, λ3,λ4 • Multihop approachλ1,λ2, λ3,λ4 λ3 λ1,λ2, λ3,λ4 λ4 8 Reconfigurable Wavelength Routing node Reference 17
  9. 9. IP/WDM network Model IP NCM • IP Routers are Network element of IP Layer • WXC, WADM are Network element WDM NCMWRS of WDM Layer • Overlay model: IP layer and optical IP NCM layer are managed and controlled independently Over Lay Model • IP-NCM, WDM-NCM, UNI • Integrated IP/WDM: Functionality of both IP and WDM are integrated at WRS each node. + control Reference 18:Ch 9, Page 347-351 9 Integrated Model
  10. 10. Optical Packet switching • Large gap between IP routeHeaderSync Header Guard Payload Payload Guard processing and the capacity of Sync WDM because of • Format of an optical Packet • Electrically Store and • Header encoded at lower speed forwarding technique • Payload duration is fixed • Payload Variable bit rate up to 10 Gb/s • Header and payload at the same wavelength • One possibility is packet • Guard time to take care of delay variation • Sync bit used for packet synch switching in optical domain Demux Mux instead of electrical domain • Statistical Multiplexing Signal • Hardware cost FDL Synchronizer Switching Fabric Regenerator • Premature state O/E O/E • Other Possible solutions in Header Payload Switch Payload electrical domain are Delineation Position Control Unit Delineation – Fast lookup – Parallelism of the forwarding Header Header Recovery updating – Label switching Technique A Generic Optical Packet switching node structureReference 18:Ch 9, Page 365-366 10Reference 19,20
  11. 11. Optical Burst Switching Core Router Edge Router Access Network Access • It Combines the advantages of Network OCS and OPS Access Network • No buffering and Electronic Processingλ0 Control Channelλ1 • High bandwidth utilization Data Channel 1 λ2 Data Channel 2 • Burst is aggregating a no of IP λ1 λ1 λ0 λ1 λ2 λ2 FDL λ0 λ1 λ2 datagram destined for same Fiber 1 FDL λ2 Optical egress router in the ingress Switching λ0 λ1 FDL Network λ1 router λ0 λ1 λ2 λ2 λ0 λ1 λ2 λ2 FDL Fiber 2 Demux Mux • Control burst and Data Burst λ0 Control IM OM Burst λ0 λ0 IM Processing OM • Node Architecture Buffer Optical Burst Switching node Routing And Architecture Table Scheduler Reference 18:Ch 9, Page 351-355 11 Reference 21
  12. 12. MPLS approach in WDM network IP network MPLS Network WRS IP network MPLS Back bone for IP network IP Over MPLS Over WDM• MPLS is the backbone for IP network.• MPLS approach for OCS is Known as LOCS or MPλS• MPLS approach is suitable for OBS and OPS using LOBS and LOPS respectively• If Label of the MPLS is mapped with λ of the WDM network, then IP-MPLS frame work enables direct integration of IP and WDM Reference 22,23 12
  13. 13. MPLS and Optical Network• MPLS is the key components for 3rd generation Transport networks.• MPLS Architecture is defined in RFC 3031 .• Operations of Label switch router (LSR), Label assignments, and Label swapping.• What is label switching and how it is different than traditional internets ?• Correlations between MPLS label value and optical wavelength Reference 1, Chapter 9 13
  14. 14. Advantage of Label Switching • Speed, delay and jitter: Faster than traditional IP forwarding • Scalability: Large no IP address can be associated with few labels • Resource consumption: Less resource for control mechanism to establish Label switch Path (LSP) • Route control: More efficient route control than destination based routing • Traffic Engineering: Allows network provider to engineer the link and nodes in the network to support different kind of traffic considering different constraints. • Labels and Lambdas: Wave length can be used for Label and optical router capable of O/O/O can forward the traffic with out any processing delayReference 1, Ch 9 14
  15. 15. The forwarding Equivalence Class (FEC) • What is FEC? – It associates an FEC value with destination address and a class of traffic. – The class of traffic is associated with a destination TCP/UDP port no and/or protocol ID field in the IP datagram header. • Advantages of FEC – Grouping of packet into classes – For different FEC we can set different priorities – Can be used for efficient QOS operation 15Reference 1, Ch 9, page 151
  16. 16. Types of MPLS nodes• Ingress LSR: – User Traffic classifies into FEC. – It generate MPLS header and Ingress assign it an initial label. LSR – If QOS is implemented then LSR will condition the traffic Transit LSR• Transit LSR – Uses the MPLS header for forwarding decision – It also performs label swapping – Not concerned with IP header Egress LSR• Egress LSR – It removes MPLS header The MPLS nodes 16Reference 1, Ch 9, page 152
  17. 17. Label Distribution and Binding• MPLS control plane perform the followings: – Advertising a range of Label values that that an LSR want to use. – Advertising of those IP address which are associated with Labels – Advertising of QOS performance parameter and suggested routes• Label Distribution Protocol (LDP) developed for MPLS by IETF• Constraint based LDP ( CR-LDP) is an extension of LDP which emulates circuit switched networks and also support Traffic Engineering operations.• RSVP Path and RESV message of RSVP-TE(extension of RSVP) also support Label binding and distributions.• Extension to BGP is also another method.• Generalized MPLS extended the RSVP and and LDP for optical network. 17Reference 1, Ch 9, page 153
  18. 18. Label swapping and Traffic forwarding • LSR forwarding table map the IP Incoming Label and interface to L3 an Outgoing Label and interface. 3 Destination Network IP el st Lab ue q Re • An LSR may explicitly request a IP L2 Request Label binding for an FEC from Label 2 the next hop. • Ingress LSR analyzes the FEC l 1 L1 Re abe IP field and correlate the FEC with que L st a Label, encapsulate the datagram. Source network IP • The Transit LSR process only label header based on the LSR Label allocation and MPLS forwarding forwarding table. 18Reference 1, Ch 9, Page 154 and Reference 2, Ch 5, Page 151
  19. 19. MPLS Support of Virtual Private Network• MPLS can be used to support VPN customers with very simple arrangement.• It is possible by label stacking : Placing of more than one Label in the MPLS header. Customer 1 Customer 1 IP 33 34 IP 33 35• This concept allows certain Label to be IP 32 34 IP 32 35 processed by the node while others are ignored. IP 31 IP 31 34 IP 31 35 IP 31• VPN backbone can accommodate all traffic with one Customer 2 LSR A LSR C Cust 2 set of Labels for the LSP in the back bone. LSR B IP 32 VPN IP 32• The customers Labels are pushed down and are IP 33 not examined in the through the MPLS tunnel. IP 33 Customer 3 Customer 3• When the packet arrive at the end of the VPN backbone LSP then the LSR pops the Labels. Label Stacking in VPN• Assumptions: – Customers at the same ends of the MPLS end to end path. – Customers have the same QOS requirements and FEC parameters Reference 1, Ch 9, page 155 19
  20. 20. MPLS Traffic Engineering• It deals with Performance of network.• High performance required for Customer’s QOS need.• Methodologies are Measurement of Traffic and Control of Traffic.• RFC 2702 specify the requirement of TE over MPLS.• Objective of TE are Traffic Oriented and Resource Oriented performance enhancement.• Traffic oriented performance objective are minimizing Traffic loss, minimizing delay, maximizing throughput and enforcement of SLAs.• Resource oriented performance objective deals with Communication Links, Routers and Servers.• Efficient management of the available bandwidth is the essence of TEReference 1, Ch 9, page 156-157 20
  21. 21. MPLS Traffic Engineering Continued…• Trunks:Aggregation of Traffic flow of the same class which are place inside an LSP• MPLS TE concerns with mapping of Traffic trunk on to physical links of a network through Label switched path.• MPLS TE is getting extended from Label switched path (LSP) to Optical switched path( OSP) for 3rd generation Transport network.• LDP,CR-LDP, RSVP-TE and OSPF (Extension) have been developed to provide signaling capabilities for MPLS. 21
  22. 22. Multi Protocol Lambda switching (MPλS)• MPλS is the framework for inter working Optical networks and MPLS. Label Mgt MPLS Control Plane• MPLS and Optical network both have LSP control plane to Manage the user traffic. Cross Connect table λ Mgt• MPLS Control Plane deals with Label Optical Control Plane distribution and binding an end to end OSP LSP Cross Connect Table• The MPLS and Optical Control Plane Optical Control Plane deals with setting up wavelength, optical coding scheme (SDH/SONET), transfer rates, Protection switching options. WDM• Reference 3 and 4 discussed about network adapting the MPLS TE Control Plane for MPLS network optical Cross Connect. MPLS network over WDM networkReference 1, Ch 9, page 158 22
  23. 23. Relationship of OXC and LSR operations Label Switch Router Optical Cross Connect Sending Receiving (LSR) (OXC) Node NodeData Transfer Label Swapping Connect optical Channel USER USER operation to transfer of one Input port to an labeled packet from an Output port MPLS MPLS Input port to an Output port Optical OpticalControl Plane Discovery,distribute Discovery,distribute and and maintain relevant maintain relevant state state information information related with related with MPLS. optical Transport network (OTN) MPLS and Optical network Layered modelForwarding Forwarding Forwarding informationinformation information Label is is implied in the data appended with Data Channel. PacketStorage of Input - output relation Input - output relation isswitching is maintained in Next maintained byinformation hop label forwarding Wavelength forwarding entry (NHLFE) information base Reference 1, Ch 9, page 159 23
  24. 24. MPLS and MPλS Correlation MPLS MPλS Map Label to User WavelengthKey aspect Label Value Optical Wavelength Ingress LSR/OXCIngress Node Role of Ingress Node on MPLS Label is Process the user Traffic, termed correlated with λ as Ingress LSR appropriate wavelength, termed as LSR/OXC Transit PXCCore node Termed as Transit LSR Termed as Transit PXC, used to process the wavelength to make the Map wavelength routing decisions. User to Label EgressPath Termed as Label switch Termed as Optical LSR/OXC Path (LSP) switched path(OSP) Processing of user Traffic in the MPλS Reference 1, Ch 9, page 160 24
  25. 25. MPLS and Optical TE similarities • MPLS term Traffic trunk = Optical Layer Term Optical Channel trail • Attributes of Traffic for MPLS TE: – Traffic Parameters: Indicate BW requirement of traffic trunk – Adaptive attributes: Sensitivity and Possibility of re-routing of trunk – Priority attribute: Priority of path selection and path placement for trunk – Preemption attribute: Whether a traffic trunk can preempt an existing trunk – Resilience attribute: Survivability requirement of Traffic trunk – Resource class affinity attribute: Restrict route selection to specific subset of resourcesReference 1, Ch 9, page 162 25
  26. 26. Possibilities for the MPλS Network • Following work remain in Reference 4 which needs to be done to complete the MPλS Network: • Concept of link bundling. • Distribution of OTN topology , available bandwidth, available channels and other OTN topology state using extension of IS-IS or OSPF • Exploring the possibilities of fiber termination in the same device which perform the role of OXC and IP router. • Uniform Control Plane for LSR and PXC as close interaction are needed between Control and Data plane for the interwork of Label and wavelength. • How to increase the utilization of the optical Channel trail in case traffic in the LSP mapped with Optical channel is low.Reference 1, Ch 9, page 163-165 26
  27. 27. IP, MPLS and Optical Control Plane• 3rd Generation transport networks encompasses three Control plane. IP Control Plane (Routing Layer)• All the above control plane need to be Data Plane coordinated to take the benefit of the (Forwarding) Mapping of followings: IP Address to MPLS Label – Route discovery of IP control Plane MPLS Control Plane • Routing protocol advertises and discover (Binding Layer) address as well as routes – Traffic Engineering capability of MPLS Data Plane control plane Mapping of (Forwarding) • MPLS Label distribution protocol will bind MPLS Label the IP address with Label to wavelength – Forwarding speed of optical data plane Optical Control Plane • MPLS Label will be mapped with (λ Mapping Layer) wavelength • Optical node can perform PXC –based O/O/O operation Data Plane (λ Mapping Layer) • O/E/O based Label label swapping will not be needed. Label • Ideally same wavelength can be used on User Payload IP Header Header each OSP segment. Inter working of three Control Plane 27Reference 1, Ch 10, page 170
  28. 28. Optical Control Plane • The requirement of Optical Control Plane as specified in Reference 5 • Permanent Optical channel setup by NMS by network management protocol Control Control • Soft permanent optical channel by NMS Control using network generated signaling and routing protocol • Switched Optical Channel which can be setup by customer on demand using signaling and Routing protocol Data • The Optical Node consist of OXC and OXC OXC Optical network control plane Optical Network Node Optical Network Node • Between two neighboring node there is pre configured control channel which may In Optical Node Model band or Out of band. • Switching function is done by OXC but it is based on how cross connect table is configuredReference 1, Ch 10, page 169 and Reference 6, Ch 14, page 427 28
  29. 29. A Frame work for IP Over Optical • Optical network control plane should utilize IP based protocol for dynamic provisioning and restoration of light path with in and across Optical sub- network • Two general model discussed in Reference 7. Unified Service model: • IP and Optical Network are treated as a single integrated network from a control plane view. • Edge router can create a lightpath with specified attributes, or delete and modify lightpath • When a router are attached to a single optical network. A remote router could compute an end to end path across the optical internetwork. • Once lightpath is established forwarding adjacency between the router is developed. Domain Services model: • Standardized signaling like RSVP-TE or LDP across the UNI is used for the following four services: LightPath creation, Lightpath deletion, Lightpath modification and Lightpath status enquiry • The protocol for neighbor and service discovery are separate like LMP 29Reference 1, Ch 10, page 173-174
  30. 30. Interconnections for IP over Optical • Transport of IP datagram over optical network Peer model • Single control plane runs over over both IP and Optical domain • Common routing protocol like OSPF or IS-IS with appropriate extension can be used for the distribution of topology information • Opaque LSA for OSPF and Extended TLV for IS-IS can be used. Overlay model • Supported by Optical domain service interconnect (ODSI) • IP domain routing, topology distribution and signaling protocol are independent of Optical domain routing, topology distribution and signaling protocol • Interconnection between signaling and routing are accomplished UNI defined procedures. Augmented model • Separate routing instances in the IP and Optical domains but information from one routing instances is passed through the other routing instances. 30Reference 1, Ch 10, page 175
  31. 31. Generalized MPLS use in optical network • Purpose of GMPLS development: (Reference 8) • To support MPLS operation in optical network with ability to use the optical technologies as » Time division ( SONET ADM) » Wavelength » Spatial switching( Incoming Fiber to out going fiber) • GMPLS assume that forwarding decision based on time slot , wavelength and physical ports. • GMPLS Terminology: 4. Packet switch capable (PXC): Process traffic based on packet/cell/frame boundaries 5. Time division Multiplex capable (TDM): Process Traffic based on a TDM boundary, such as SONET/SDH node. 6. Lambda-switch capable (LSC): Process traffic based on the Optical wavelength 7. Fiber switch capable (FSC): Process traffic based on the physical interface. 31Reference 1, Ch 10, page 177
  32. 32. Generalized MPLS use in optical network continued…• GMPLS = Extension of MPLS to support various switching technology (RFC 3945) Packet LSP• Following switching technology is considered: Layer 2 LSP • Packet switching: Forwarding capability packet based, IP Router Time slot LSP • Layer2 switching: Forwarding data on cell or frame: Ethernet, ATM • TDM or Time slot switching: Forwarding data based on time slot: λ- LSP SONET,DCS, ADM • Lambda switching: Performed by OXC • Fiber switching: Performed by Fiber switch capable OXC Fiber LSP• GMPLS control plane focus on full range of switching technology• Natural Hierarchy of Label stacking in GMPLS: GMPLS Label stacking LSP Packet LSP over Layer 2 LSP over over Time slot LSP over λ- switching LSP over Fiber switching LSP 32 Reference 26, 27
  33. 33. GMPLS Control Plane• Optical network is becoming the Transport network for IP traffic Routing protocol (IP over Optical) Resource discovery and dissemination CSPF path computation Wave length Assignment• IP centric optical control plane is the best choice Restoration Signaling Management• GMPLS control plane for Optical network contains Routing, Signaling and Restoration Management GMPLS Control Plane for Optical Network 33Reference 6, Ch 14, page 428
  34. 34. Resource Discovery and Link-state Information Dissemination• Each Optical node need to know the Global topology and resource information, which is possible by broadcasting local resource use and neighbor connectivity information by each optical node.• It can be done the OSPF (Reference 9) and its extension ( Reference 10)• It can also be done by IS-IS (Reference 11) and its extension (Reference 12)• Here neighbor discover require inband communication which is possible for Opaque OXC with SONET termination.• For Transparent OXC neighbor discovery generally utilizes a separate protocol such as Link management protocol ( Reference 13)• Issues: Scalability problem for link addressing and Link state advertisement• Solutions: • Unnumbered links: Globally unique end node ID ( LSR ID) plus local selector ID • Link Bundling: The link attribute of multiple wavelength channel of similar characteristics can aggregated. 34 Reference 6, Ch 14, page 428-429
  35. 35. CSPF Path computation• CSPF = SPF + resource constraint + policy constraint : To achieve the MPLS TE objective RFC 2702• Such path computation is NP complete and Heurestic have to be used.• The objective of path computation in optical network is to minimize the resource required for routing light paths for a given SLA.• For optical network CSPF algorithm needs to be modified for the following reason • Link Bundling and Restoration Path Computation• The Solution is Shared Risk Link Group (SRLG): Administrative group associated with some optical Resources that probably share common vulnerability to a Single Failure. • Example: Fiber in the same conduit can be assigned with one SRLG 35
  36. 36. Wavelength Assignment Fiber 1 Fiber 1• Wave length Continuity constrained for λ1 λ1 λ2 Transparent OXC λ3 λ2 λ3 λ1• Opaque OXC and wave length λ2 λ1 λ2 Conversion λ3 λ3 Fiber 2 Fiber 2 Transparent OXC• Wave Length Assignment Problem is constrained to the CSPF algorithm λ1 λ2 λ1 λ2 λ3 λ3• Wave length assignment λ4 λ4 • At the Source λ5 λ5 λ6 λ6 • Random wave length assignment Fiber 1 Fiber 1 Opaque OXC • Dynamic wavelength Reservation 1 Reference 6, Ch14, Page 430 Reference 24,25 3 2 36 Light Path Demand set in a ring
  37. 37. Restoration Management• Difference between Optical Layer protection with IP layer MPLS Layer.• Management and co-ordination among multiple layer is an important issue.• Optical Protection mechanism can be classified as follows: • Path Protection • Link Protection• Path Protection classified as follows: • Disjoint Path Protection: 1+1 , 1:1 and M:N • Link-dependent Path protection• Restoration Management: Failure detection, Failure notification and Failure restoration.• Detection by lower layer impairments, higher layer link probing.• Time for restoration is due to restoration path computation and traffic rerouting from primary path to restoration path 37 Reference 6, Ch14, Page 431
  38. 38. Signaling• Signaling is distributed path establishment operation across Optical network• Major Operation of Light Path signaling are Light Path setup, Teardown and Abort DST• Light Path Setup: SETUP, SETUP ACK, SRC INT_A INT_B SETUP NAK• Light Path commitment Phase: ABORT• Light Path Teardown : TEARDOWN and SETUP TEARDOWN ACK SETUP• Addressing Issue due to High no of entity in SETUP Optical network: Unique IP to OXC and other resources through Selector• Each node will Maintain a Light Path table SETIP ACK Time to record the Lightpath ID, Incoming/ Out SETIP ACK going Port no, SRLG so on.. SETIP ACK 38 Reference 6, Ch14, Page 432-435
  39. 39. GMPLS Signaling Functional Requirements• Same switching functionality for both end LSR• GMPLS extends MPLS Signaling in many aspect• Generalized label is defined with enough flexibility to represent Label for different switching type.• Label suggestion capability by the upstream node will reduce the LSP setup delay.• Label set: Upstream restrict the label selection of the down stream to acceptable limit.• GMPLS support Bi-directional LSP setup.• Explicit Label label selection offers capability of explicit label selection on a specific on an explicit route• GMPLS data channel and control channel may be separate.• GMPLS signaling for fault handling should minimize the packet loss. 39 Reference 6, Ch14, Page 435-436
  40. 40. GMPLS Traffic Engineering Extension• MPLS-TE has two metrics: • Regular link metric: used in traditional IP routing • Traffic Engineering link metric: used for constrained based routing• GMPLS Traffic Engineering Link is Logical Link with Traffic Engineering properties.• The Management of Traffic Engineering link is conducted by LMP• For GMPLS LSP may be taken as TE link but routing adjacency need not to be established directly between the two end node of the LSP• For GMPLS link bundle can be advertised as TE link Reference 6, Ch14, Page 436 40
  41. 41. GMPLS Adjacencies• Three types of adjacencies: • Routing: Neighbors of the routing protocol • Signaling: Peering relationship of two nodes established by signaling • Forwarding:TE link that transit three or more GMPLS nodes in the same instance.• If Signaling adjacency is established over TE link then TE link is used as tunnel to establish LSP over it. Reference 6, Ch14, Page 436-437 41
  42. 42. IP – Centric Control PlaneIP Network Receive incoming message Process the request with the help of other module Initializing the control Plane UNI Optical Network Main Module (MM) Resource Protection/ Connection Management Restoration Module Module Module (CM) (RMM) (PRM) •Light Path Signaling •Maintenance •Survivability •Routing and wavelength Assignment (RWA) •Fault Monitoring •Topology and Resource Discovery •Fast Protection/ •QOS support Restoration Reference 6, Ch14, Page 461-469 42 Reference 28
  43. 43. Connection Module (CM) IP Network •Connection Request Message Contents •Light Path ID •Light Path Type (Primary/ Protection) UNI •Routing Path •Assigned wave Length •QOS type Optical Network •SRLG list of Primary Path •At each hop, request Message is processed •Destination node send ACK along the same path •If there is resource conflict NAK is sent backLight Path ID Status QOS Input Output λ IDSRC DEST SEQ (Creating/ Type Port PortNODE NODE NUM Reserved/ID ID Active/ ID ID Deleted) 43
  44. 44. Connection Module (CM) Continued…… 1 Reserved Creating 5 Processing of Lightpath signaling 4 2 6 Resource Reservation/ Lightpath State Transfer Deleted Active Release 3 Determination of Input/ Output port QOS= Protection Sensitive from the LTNAK If it is Primary Path and wavelength status “ available” change the status to “ Used Preemptible” QOS = best EffortIf Assigned wavelength is available If it is Protection LightPath and wavelength status “ available” Set the wavelength status Set the status to” Reserved” “ Used Preemptible” Else Check the SRLG list QOS = Mission Critical If Assigned Wavelength is available 1. Protection Path: Reservation Ack Change the status to to “ Used and Non-perrmptible” 2. Failure on Primary path 3. Tear Down abort Else abort the existing lightpath on this wavelength. Then 4. NAK Change the status to to “ Used and Non-perrmptible” 5. Primary Path : Setup ACK44 6. Tear Down Abort
  45. 45. Resource Management Module• Functionality: Resource Discovery, IP Network Maintenance, QOS support, RWA• Neighbor discovery mechanism by sending UNI Hello Message on all out going link.• Local Connectivity Vector (LCV): Store the Optical cost of the Adjacent Node. Network• If LCV is updated , it is broadcasted to the network• Local resource availability stored in Local Port Peering λ1 status λ2 status … Resource Table (LRT) Node no • “λi status” indicate state of ith wavelength in ID the fiber attached to the port λ1 SRLG list λ2 SRLG list • Possible states are “used and preemptable” , “used and non-preemptable” , “Reserved”, “Available” and “ Faulty” • “λi SRLG list” stores the SRLG information of the primary path whose protection path has reserved the wavelength (λi status = Reserved) Local Resource Table (LRT) 45
  46. 46. Resource Management Module Continued….• Each node build its own Topology Optical connectivity Matrix (TCM) with N Network nodes.• Each row of TCM is the LCV of the Node Node Node Node Node Node node I plus a time stamp. 1 2 3 4 5 6 Node 1• RMM also maintain a Global Resource Node Table (GRT) consisting of LRT of all 2 nodes. Node 3• RMM utilize different RWA algorithm Node to support QOS. 4 Node 5• QOS support: Node • Best-effort service 6 • Mission critical service • Protection Sensitive Matrix Topology Connectivity Matrix 46
  47. 47. Protection and Restoration Module• Functions: Setup Co-ordination of Primary and protection Light Path, Fault detection, and notification. Connection Request NAK/ACK• Fault can be detected by as follows: • Low level impairments • Higher layer link probing Control Plane of Node A Control Plane of Node A• Failure can happen for Control Plane or OXC. (MM) (MM)• Failure indication Signal (FIS) send to the source node. (CM) (RMM) (PRM) (CM) (RMM) (PRM)• If Qos requirement is Restoration the restoration Path will be calculated. Control Control Control• If Qos requirement is Protection then source node will invoke the setup signal for the Lightpath previously reserved. Data OXC OXC• For Mission critical destination node detect the failure of the primary Lightpath and turn to Optical Network Node A Optical Network Node B protection path. 47
  48. 48. Optical Internetworking and Signaling across Network Boundary• Need for Inter-domain Optical network• Need for standard • Addressing scheme to identify light path end points • Routing Protocol • Standard signaling protocol across Network to Network interface NNI • Restoration procedure • Policies that affect the flow of Control Information• Solution is by implementing: • External Signaling Protocol (ESP): Used for Signaling across NNI • Internal Signaling protocol( ISP): May be different for different network NNI• Possibility of BGP extension is being studied for Routing .• Possibility of CR-LDP or RSVP-TE extension is being studied for Signaling across the network 48 boundary.
  50. 50. Conclusion• Development and implementation of GMPSL over the existing technology can only bring the reality of IP over WDM• Performance of GMPLS in the hybrid scenario should be simulated. 50
  51. 51. References1. Optical Networks, Third Generation Transport Systems by Uyless Black2. Optical Network Control Architecture, Protocols, and Standards by Greg Bernstein• M u lt ip r o t o c o l L a m b d a S w it c h in g : C o m b in in g M P L S T r a f f ic E n g i n e e r i n g C o n t r o l w i t h O p t i c a l C r o s s c o n n e c t s b y Da n ie l A wd u c h e , M o v a z Ne t wo r k s Y a k o v R e k h t e r , J u n ip e r Ne t wo r k s , IEEE Communications Magazine • March 2001• Multi-Protocol Lambda Switching: Combining MPLS Traffic Engineering Control With Optical Crossconnects draft-awduche-mpls-te-optical-03.txt5. C o n s id e r a t io n s o n t h e d e v e l o p me n t o f a n Op t ic a l C o n t r o l P l a n e , I n t e r n e t Dr a f t Do c u me n t : d r a f t - f r e e l a n d - o c t r l - c o n s - 0 1 .t x t b y I P - Op t ic a l W o r k in g Gr o u p• I P Ov e r W DM : B u il d in g t h e n e x t Ge n e r a t io n Op t ic a l I n t e r n e t , E d it e d b y S u d h ir Dix it• I P o v e r Op t ic a l Ne t wo r k s : A F r a me wo r k : d r a f t - ie t f - ip o - f r a me wo r k - 0 0 .t x t b y B a l a R a j a g o p a l a n15. Generalized MPLS - Signaling Functional Description: draft-ietf-mpls- 51 generalized-signaling-05.txt by Network Working Group
  52. 52. Reference Continued….10. OSPF Extensions in Support of Generalized MPLS: draft-ietf-ccamp-ospf-gmpls-extensions-00.txt11. Use of OSI ISIS for Routing in TCP/IP and Dual Environments: RFC 119512. IS-IS Extensions in Support of Generalized MPLS: draft-ietf-isis-gmpls-extensions-04.txt13. Link Management Protocol (LMP) : draft-ietf-ccamp-lmp-10.txt14. http://www.cs.columbia.edu/~hgs/internet/traffic.html15. WDM Technologies, Volume III - Optical Networks - 2004 - (By A.K.Dutta)16. http://bgp.potaroo.net/17. Design of Logical Topologies for Wavelength-Routed Optical Networks, Rajiv Ramaswami,IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 14, NO. 5, JUNE 199618. WDM Optical Networks: Concept, Design and Algorithm by C. Siva Ram Murthy19. Transparent Optical Packet Switching: The European ACTS KEOPS Project Approach,JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 16, NO. 12, DECEMBER 1998 20. High-capacity Multi-service optical label switching for the next generation Internet,IEEE Optical Communications * May 200421. Choices, Features and Issues in Optical Burst Switching, Optical Network Magazine, Vol.1, no.2, pp 36-44, April 2000  52
  53. 53. Reference Continued….22. On IP-over-WDM Integration, IEEE Communications Magazine • March 2000• Labeled Optical Burst Switching for I P-over-W DM Integration, IEEE Communications Magazine September 2000• Efficient Distributed Control Protocols for WDM All-Optical Networks*Computer Communications and Networks, 1997. Proceedings• Lightpath Communications: An Approach to High Bandwidth Optical WDM’s by Imrich Chlamtac, IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 40, NO. 7. JULY 1992• Generalized Multiprotocol Label Switching: An Overview of Routing and Management Enhancements, IEEE Communications Magazine • January 2001• Generalized Multi-Protocol Label Switching (GMPLS) Architecture, RFC 3945• On an IP-Centric Optical Control Plane, IEEE Communications Magazine September 2001 53