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Agenda

Agenda. Protocol Layering Why Simplify? First Steps: MP S Emerging Optical Switching Technologies:. Protocol Layering. Application. We know from experience that we can't run applications directly over media Solution: Protocol Layering. FIBER. Protocol Layering. Application.

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Agenda

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  1. Agenda • Protocol Layering • Why Simplify? • First Steps: MPS • Emerging Optical Switching Technologies:

  2. Protocol Layering Application We know from experience that we can't run applications directly over media Solution: Protocol Layering FIBER

  3. Protocol Layering Application • Applications include… • Leased lines • National telephone services SDH / SONET Fiber

  4. Protocol Layering Application IP Internet services emerge SDH / SONET Fiber

  5. Protocol Layering Application IP IP PoA PoS ATM • ATM is introduced as… • Traffic Engineering layer in the Internet • Native service SDH / SONET Fiber PoA - Packet over ATM PoW - Packet over WDM GE - Gigabit Ethernet PoS - Packet over SDH

  6. Protocol Layering Application IP IP PoA ATM Wavelength Division Multiplexing appears as a mechanism to increase capacity on a fibre SDH / SONET WDM Fiber

  7. Native Ethernet services appear to be a cost-effective alternative, but need SONET/SDH framing Protocol Layering Application IP IP PoA PoS ATM GE SDH / SONET WDM Fiber

  8. Protocol Layering MultiProtocol Label Switching appears as alternative to ATM Traffic Engineering Application IP IP PoA ATM MPLS GE PoS PoS SDH / SONET WDM Fiber

  9. Protocol Layering Digital Wrapper appears as an early "SONET-lite" technology for direct Packet-over-Wavelengths Application IP IP PoA ATM MPLS GE PoS SDH / SONET PoW Digital Wrapper WDM Fiber

  10. Data Transfer Over Frame-based Networks File TCP IP Frame (Ethernet, FR, PPP)

  11. Data Transfer Over Cell-based Networks File TCP IP Adaptation ATM Cells

  12. Agenda • Protocol Layering • Why Simplify? • First Steps: MPS • Emerging Optical Switching Technologies: • Optical Packet Switching • Optical Burst Switching

  13. SONET SDH WDM What do these layers do? • IP is the service • Addressing • Routing • ATM provides Traffic Engineering • SONET/SDH provides… • Provisioning control • Service restoration • OAM statistics • Low error rate • WDM provides capacity IP Over ATM Over SONET/SDH Over DWDM

  14. Control Plane v Data Plane The data plane actually carries the information while the control plane sets up pathways through the data plane MPLS LSRs and MPS OXCs both solve performance scalability problem by decoupling control and data planes

  15. An IP Router:The Data Plane Control Processor OUTPUTS Packet Backplane Outbound Packet INPUT Inbound Packet

  16. An IP Router:The Control Plane Routing Table Router Applications eg. OSPF, ISIS, BGP Control Processor Packet Backplane Routing Updates

  17. Bandwidth Bottlenecks • Routing Protocols Create A Single "Shortest Path" C1 C3 C2 "Longer" paths become under-utilised Path for C1 <> C3 Path for C2 <> C3

  18. Engineering-Out The Bottlenecks • ATM Switches Enable Traffic Engineering C1 C3 C2 PVC C1 <> C3 PVC C2 <> C3

  19. What Is MPLS?A Software Upgrade To Existing Routers • MPLS…a software upgrade? + = Router S/W LSR

  20. What Is MPLS?A Software Upgrade To ATM Switches • MPLS…a software upgrade? + = ATM Switch ATM LSR S/W

  21. IP #L1 IP #L2 IP #L3 ROUTE AT EDGE, SWITCH IN CORE IP IP IP Forwarding IP Forwarding LABEL SWITCHING

  22. UDP-Hello UDP-Hello TCP-open Initialization(s) Label request IP #L2 Label mapping MPLS: HOW DOES IT WORK TIME TIME

  23. IP1 IP1 IP1 IP2 IP1 IP2 IP1 IP2 #L1 #L1 #L2 #L3 #L3 #L2 IP2 IP2 Forwarding Equivalence Classes LSR LSR LER LER LSP Packets are destined for different address prefixes, but can be mapped to common path • FEC = “A subset of packets that are all treated the same way by a router” • The concept of FECs provides for a great deal of flexibility and scalability • In conventional routing, a packet is assigned to a FEC at each hop (i.e. L3 look-up), in MPLS it is only done once at the network ingress

  24. 3 MPLS BUILT ON STANDARD IP 47.1 1 2 1 3 2 1 47.2 3 47.3 2 • Destination based forwarding tables as built by OSPF, IS-IS, RIP, etc.

  25. MPLS Takes Over • MPLS LSRs Enable Traffic Engineering C1 C3 C2 LSP C1 <> C3 LSP C2 <> C3

  26. MPLS Path Creation:Quality of Service Refinements • Source device (S) determines the type of path on the basis of the data S D Low delay (preferred for VoIP traffic) High bandwidth (preferred for FTP)

  27. Core Router Core Router ATM Switch ATM Switch MUX MUX SONET/SDH ADM SONET/SDH ADM SONET/SDH DCS SONET/SDH DCS SONET/SDH ADM SONET/SDH ADM MUX MUX ATM Switch ATM Switch Core Router Core Router Typical IP Backbone (Late 1990’s) • Data piggybacked over traditional voice/TDM transport

  28. IP routing protocols (OSPF, BGP) Point-to-point DWDM links (Linear or ring SONET topologies) SONET SONET IP/PPP/HDLC packet mappings to SONET frames (OC-48, OC-192) Gigabit IP Router Demux Mux Wavelength laser transponders

  29. Why So Many Layers? • Router • Packet switching • Multiplexing and statistical gain • Any-to-any connections • Restoration (several seconds) • ATM/Frame switches • Hardware forwarding • Traffic engineering • Restoration (sub-second) • MUX • Speed match router/ switch interfaces to transmission network • SONET/SDH • Time division multiplexing (TDM) • Fault isolation • Restoration (50mSeconds) • DWDM • Raw bandwidth • Defer new construction • Result • More vendor integration • Multiple NM Systems • Increased capital and operational costs

  30. MUX becomes redundant IP trunk requirements reach SDH aggregate levels Next generation routers include high speed SONET/SDH interfaces Core Router (IP/MPLS) SONET/SDH DWDM IP Backbone Evolution Core Router (IP/MPLS) FR/ATM Switch MUX SONET/SDH DWDM (Maybe)

  31. Collapsing Into Two Layers IP Service (Routers) Optical Core Optical Transport (OXCs, WDMs, SONET ?)

  32. Core Router Core Router STM-16 STM-64 POS Transponder Transponder O/EO O/EO OA WDM Mux/demux WDM Mux/demux WDM Network Architecture

  33. IP core routers with optical interfaces will be interconnected to DWDM equipment via a transponder device. Transponders perform the function of translating a standard optical signal (normally at 1330 nm) from a router line card to one of several wavelengths on a pre-specified grid of wavelengths (sometimes called 'colors') as handled by the DWDM equipment. This could be used to implement an OC-48 or OC-192 circuit between core routers in an IP backbone. It is worth pointing out that packet-over-SONET (POS) interfaces are used, so there is SONET framing in the architecture to provide management capabilities like inline monitoring, framing and synchronization. The architecture is still referred to as IP-DWDM as there is no discrete SONET equipment between the core routers and the optical transmission kit. The optical link might also include optical amplifiers and, if the distance is large enough, electronic regeneration equipment.

  34. It is very important to differentiate between functional layers and layers of discrete equipment. In the diagram, many functional layers can be integrated within a single equipment layer. This is emphasized by the multilayer stack on the right hand side, which involves two discrete layers of equipment, IP routers and DWDM transmission. In the case of IP routers, there are actually four distinct functional layers (IP, MPLS, PPP and SDH). The notion of collapsed layers is therefore only applicable to the number of network elements involved, rather than the numeric of functional layers. It is perhaps more meaningful to refer to increasing integration of transmission network architectures

  35. The Problem Should carriers control their next-generation data-centric networks using only routers, or some combination of routers and OXC equipment? The debate is really about the efficiency of a pure packet-switched network versus a hybrid, which packet switches only at the access point and circuit switches through the network.

  36. OXC OXC OXC (IP-aware) OXC CONTROLLER (IP-aware) OXC CONTROLLER (IP-aware) OXC CONTROLLER IP/MPLS module IP/MPLS module IP/MPLS module Transponder Interface Transponder Interface Transponder Interface Transponder Interface Transponder Interface Transponder Interface Tx’s Tx’s Tx’s Rx’s Rx’s Rx’s Local Add / Drop Local Add / Drop Local Add / Drop Node B: Nodal Degree of 2, 100/fiber 2X2X100 ports to add/drop Node B Node A Node C

  37. IP over Optical Network Architectural Models

  38. We Need Optical Traffic Engineering • Classically the OXC "control plane" is based on the NMS • Relatively slow convergence after failure (from minutes to hours) • Complicates multi-vendor interworking • Traffic Engineering is achieved via a sophisticated control plane… • Dynamic or automated routing become proprietary • Complicates inter-SP provisioning

  39. Solution: Optical Switching • All-optical Data Plane products are widely available today • Typically DWDM OADMs and OXCs • Some of these devices have dynamic reconfiguration capabilities • Generally via NMS or proprietary distributed routing protocols • The Control Plane of these devices remains electronic • So control messages must be sent over a lower speed channel • There are several ways to achieve this • Typical DWDM is "service transparent" • The data plane does not try to interpret the bitstreams • Implies amplification, not regeneration • Also implies that signal bit error rate is not monitored

  40. Lambda Switching Objectives • Foster the expedited development and deployment of a new class of versatile OXCs, and existing OADMs • Allow the use of uniform semantics for network management and operations control in hybrid networks • Provide a framework for real-time provisioning of optical channels in automatically-switched optical networks

  41. How Do We Label a Lambda? • Remember that the OXC is "service transparent" • Will not interpret the bitstream • May not even be able to digitally decode bits at this speed • The obvious property available is the value of the wavelength • This is why we call it "Lambda Switching"

  42. Concepts in Lambda Switching • Involves the idea of space-switching channels from an inbound port to an outbound port • Variety of space-switching technologies are appropriate • May involve wavelength translation at the outbound port • Wavelength translation is expensive • If data channels are "service transparent", how do we… • Exchange routing protocols? • Exchange signalling protocols? • Send network management and other messages that must terminate in the lambda switch?

  43. Recap: MP Label S • A technique that uses IP as the control plane for a connection-oriented, switched data plane • Initial application (focussed on reducing costs) • Traffic Engineering (put the traffic where the bandwidth is) • Emerging Applications (focussed on additional revenues) • VPNs • Voice over MPLS • ”Video over MPLS" • Future Applications • Universal Control Plane

  44. (1, 5) (4, 7, Swap) 5 7 (1, 3) (4, 27, Swap) (1, 17) (4, 123, Swap) (2, 3) (3, 17, Push) The Label Information Base • Labelled packet arrives at Port 1, with Label value "5" • LIB entry indicates switch to Port 4, and swap label to value "7" Connection Table In (port,Label) Out (port, Label, Operation) Port 1 Port 3 Port 2 Port 4

  45. (1, 2) (4, 2) (1, 3) (4, 3) (1, 1) (4, 2) (2, 1) (3, 1) The Optical Connection TableCase 1a: No wavelength translation • Channel arrives on Port 1 on 2, the "green" lambda • Connection table indicates that this channel should be space-switched to Port 4 • At Port 4, 2 is available for onward transmission Connection Table In (port,Lambda) Out (port, Lambda) Port 1 Port 3 2 Port 2 Port 4 2

  46. (1, 2) (4, 2) (1, 3) (4, 3) (2, 3) (4, 1) (2, 1) (3, 1) The Optical Connection TableCase 1b: No wavelength translation • Channel arrives on Port 1 on 3, the "blue" lambda • Connection table indicates that this channel should be space-switched to Port 4 • At Port 4, 3 is available for onward transmission Connection Table In (port,Lambda) Out (port, Lambda) Port 1 Port 3 3 Port 2 Port 4 3

  47. (1, 2) (4, 2) (1, 3) (4, 3) (2, 3) (4, 1) (2, 1) (3, 1) The Optical Connection TableCase 2: Wavelength translation • Channel arrives on Port 2 on 3, the "blue" lambda • Connection table indicates that this channel should be space-switched to Port 4 • At Port 4, 3 is already in use, so lambda is translated to 1, the "red" lambda Connection Table In (port,Lambda) Out (port, Lambda) Port 1 Port 3 Port 2 Port 4 3 1

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