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Introduction to ATM

Introduction to ATM. Cisco Systems Confidential. 0680_03F7_c3. 1. Susanne East. Product Marketing Engineer Technical Marketing seast@cisco.com. Cisco Systems Confidential. 0680_03F7_c3. 2. Agenda. Introduction ATM Fundamentals Rudimentary ATM Concepts ATM Reference Model

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Introduction to ATM

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  1. Introductionto ATM Cisco Systems Confidential 0680_03F7_c3 1

  2. Susanne East Product Marketing EngineerTechnical Marketingseast@cisco.com Cisco Systems Confidential 0680_03F7_c3 2

  3. Agenda • Introduction • ATM Fundamentals • Rudimentary ATM Concepts • ATM Reference Model • ATM Adaptation Layer (AAL) • Traffic Management • ATM Transport Standards • Campus ATM Internetworking • Wrap Up

  4. Characteristics of ATM Voice Data • Uses small, fixed-sized cells • Connection-oriented • Supports multiple service types • Applicable to LAN and WAN Cells Video

  5. Creating Cells from Packets Dest.Address SourceAddress FrameCheck Packet Data Cells Header Payload Header Payload 5 ByteHeader Header Payload 53Bytes Header Payload 48 BytePayload ATM Cell

  6. Campus Networking Evolution Traditional Network SharedEthernet Clients • Hierarchical design with broadcast control • 80/20 rule • Homogenous user communities • Moves, adds, and changes manually Corporate WAN and Internet LocalWorkgroupServers Cisco Systems Confidential 0680_03F7_c3 6

  7. Campus Networking Evolution Contemporary Network SwitchedEthernetClients Ethernet Switchwith VLAN Support • Network hierarchy maintained • Traffic patterns migrating • Client and server performance increases • Moves, adds, and changes automated Corporate WAN and Internet Campus ATM Network Centralized High-Performance Servers ATM-Attached Station(s)

  8. The Wonderful World of Acronyms AAL—ATM Adaptation Layer AAL1—See CBR AAL2—See VBR AAL3/4—See UBR AAL5—See ABR ABR—Available Bit Rate API—Application Programmer Interface B-ICI—B-ISDN Inter-Carrier Interface BUS—Broadcast and Unknown Server CAC—Connection Admission Control CBR—Constant Bit Rate CCITT—Consultative Committee for International Telephony and Telegraph CDVT—Cell Delay Variation Tolerance CLP—Cell Loss Priority CLR—Cell Loss Ratio CS—Convergence Sublayer EFCI—Explicit Forward Congestion Indicator ELAN—Emulated LAN GCRA—Generic Cell Rate Algorithm GFC—Generic Flow Control HEC—Header Error Check IISP—Interim Inter-Switch Signaling Protocol ILMI—Interim Local Management Interface

  9. The Wonderful World of Acronyms IPD—Intelligent Packet Discard LANE—Local Area Network Emulation LEC—LAN Emulation Client LES—LAN Emulation Server LECS—LAN Emulation Configuration Server LIS—Logical IP Subnet MBS—Maximum Burst Size MCR—Minimum Cell Rate MCTD—Maximum Cell Transfer Delay MPC—MPOA Client (aka Edge Device) MPOA—Multi-Protocol Over ATM MPS—MPOA Server (aka Router Server) NNI—Network-to-Network Interface OC—Optical Carrier PCR—Peak Cell Rate PMD—Physical Media Dependent PNNI—Private Network-to-Network Interface PTI—Payload Type Identifier PVC—Permanent Virtual Circuit Q.SAAL—aka Q.2100—Signaling ATM Adaptation Layer RFC1483—Multiprotocol Encapsulation over AAL5 RFC1577—Classical IP and ARP over ATM RM—Resource Management

  10. The Wonderful World of Acronyms SAR—Segmentation and Reassembly SDH—Synchronous Digital Hierarchy SONET—Synchronous Optical Network STM—Synchronous Transport Mode STS—Synchronous Transport Signal SCR—Sustained Cell Rate SVC—Switched Virtual Circuit SSCOP—Signaling Specific Convergence Protocol TC—Transmission Convergence UBR—Unspecified Bit Rate UNI—User-to-Network Interface UPC—Usage Parameter Control VBR-NRT—Variable Bit Rate-Non-Real Time VBR-RT—Variable Bit Rate-Real Time VC—Virtual Circuit (or sometimes Virtual Connection) VCC—Virtual Channel Connection VCI—Virtual Channel Identifier VC Switch—Virtual Circuit Switch VP—Virtual Path VPC—Virtual Path Connection VPI—Virtual Circuit Identifier VP Switch—Virtual Path Switch VS/VD—Virtual Source/Virtual Destination

  11. Agenda • Introduction • ATM Fundamentals • Rudimentary ATM Concepts • ATM Reference Model • ATM Adaptation Layer (AAL) • Traffic Management • ATM Transport Standards • Campus ATM Internetworking • Wrap Up

  12. Rudimentary ATM Concepts • Physical layer • Signaling • Cell format • Connection types

  13. ATM Transmission Media ATM SDH/SONET Rates Chart SDH SONET Rate—Mbps • CCITT (Consultative Committee for International Telephony and Telegraph) • ITU (International Telecommunications Union) STS-1/OC-1 51.84 STM-1 STS-3/OC-3 155.52 STM-4 STS-12/OC-12 622.08 STM-8 STS-24/OC-24 1,244.16 STM-16 STS-48/OC-48 2,488.32 Cisco Systems Confidential 0680_03F7_c3 13

  14. ATM Physical Interface Rates Framing DataRate(Mbps) Media Multi-ModeFiber Single-ModeFiber CoaxialCable UTP–5 UTP–3 STP DS1 E1 J2DS3 E3 E4 1.5442.0486.234534139 (TP)(TP) X ATM25STS 1STS3c/STM1 25.651.8155 X STS 12c/STM44B/5B (TAXI)8B/10B(Fiberchannel) 622100155 = Standardized = Proposed/In Progress X

  15. Rudimentary ATM Concepts • Physical layer • Signaling • Cell format • Connection types

  16. ATM Building Blocks • ATM signaling • UNI and NNI • Virtual connections • VCC, VP, and VC

  17. ATM Signaling Public UNIaka B-ICI Public ATM Network NNI • UNI = User-to-Network Interface • NNI = Network-to-Network Interface • Cell header content varies depending on who’s talking to whom UNI NNI NNI Private ATM Network

  18. Virtual Path and Virtual Channels Virtual Channels (VC) ATM Physical LinkVirtual Channel Connection (VCC) Virtual Path (VP) E3OC–12 Virtual Path (VP) Virtual Channels (VC) Virtual Channel(VC)Logical PathBetween ATM End Points Virtual Channel Connection(VCC)Contains Multiple VPs Virtual Path(VP)Contains Multiple VCs Connection Identifier = VPI/VCI Cisco Systems Confidential 0680_03F7_c3 18

  19. 2 1 3 ATM Switches Input Output 45 Port VPI/VCI Port VPI/VCI 1 29 2 45 29 64 • ATM switches translate VPI/VCI values • VPI/VCI value unique only per interface—eg: locally significant and may be re-used elsewhere in network 2 45 1 29 1 64 3 29 3 29 1 64 29

  20. VP and VC Switching VC Switch VCI 1 VCI 2 VCI 3 VCI 4 Port 2 VPI 1 VPI 3 VPI 2 VP Switch VPI 2 Port 1 VCI 1 VPI 1 VPI 3 VCI 2 VCI 1 VPI 4 VPI 5 VCI 2 Port 3 Cisco Systems Confidential 0680_03F7_c3 20

  21. Virtual Channels and Virtual Paths Virtual Channel Connection (VCC) • This hop-by-hop forwarding is known as cell relay Virtual PathConnection (VPC) UNI UNI NNI NNI VCSwitch VPSwitch VCSwitch VPI = 1VCI = 1 VPI = 2VCI = 44 VPI = 26VCI = 44 VPI = 20VCI = 30

  22. Rudimentary ATM Concepts • Physical layer • Signaling • Cell format • Connection types

  23. Creating Cells from Packets Dest.Address SourceAddress FrameCheck Packet Data Cells Header Payload Header Payload SARSegmentation and Reassembly Header Payload Header Payload Segmentation Happens at SourceReassembly Happens at Destination

  24. ATM Cell Header 5 ByteHeader 53 Bytes 48 BytePayload ATM Cell

  25. GFC (4) VPI (12) VPI (8) VCI (16) VCI (16) PTI CLP PTI CLP HEC HEC 48 BytePayload 48 BytePayload ATM UNI Cell ATM NNI Cell ATM Cell Header Details GFC Generic Flow Control UNI Cells Only! VPI/VCI Identifies Virtual Paths and Channels PTI Payload Type Identifier 3 Bits: 1. User/Control Data 2. Congestion 3. Last Cell CLP Cell Loss Priority Bit HEC Header Error Check 8 Bit CRC

  26. Rudimentary ATM Concepts • Physical layer • Signaling • Cell format • Connection types

  27. ATM Connection Types • PVC • SVC • Soft PVC

  28. S2 1 S6 1 1 S1 S8 S3 S5 2 2 S4 2 S7 Connection Types S2 S6 S1 S3 S5 S8 VC S4 S7 • Connectionless: Packet Routing • Path 1 = S1, S2, S6, S8 • Path 2 = S1, S4, S7, S8 • Data can take different pathand can arrive out of order • Connection Oriented: Cell Switching • VC = S1, S4, S7, S8 • Data takes the same path and arrives in sequence

  29. A B Permanent Virtual Circuit (PVC) Input Output Input Output Port VPI/VCI Port VPI/VCI Port VPI/VCI Port VPI/VCI 1 29 3 45 1 33 3 02 2 52 4 15 2 15 3 14 29 1 64 3 29 1 64 3 29 • VPI/VCI tables in network equipment updated by administrator 3 29 1 64 3 29 1 64 1 15 4 2 C 45 2 3 3 14 30 43 3 16 2 Input Output Input Output 2 1 Port VPI/VCI Port VPI/VCI Port VPI/VCI Port VPI/VCI 4 1 45 2 16 1 16 2 43 10 2 52 1 29 3 14 4 10 D 1 64 3 29 1 64 3 29 3 29 1 64 3 29 1 64

  30. A UNISignaling UNISignaling NNISignaling B Switched Virtual Circuit (SVC) Input Output Input Output Port VPI/VCI Port VPI/VCI Port VPI/VCI Port VPI/VCI 1 29 3 45 1 64 3 29 1 64 3 29 • Dynamically set up connectionsvia signaling 3 29 1 64 3 29 1 64 1 4 1 C 2 3 3 3 2 Input Output Input Output 2 1 Port VPI/VCI Port VPI/VCI Port VPI/VCI Port VPI/VCI 4 2 52 1 29 D 1 64 3 29 1 64 3 29 3 29 1 64 3 29 1 64

  31. A UNISignaling UNISignaling NNISignaling B Switched Virtual Circuit (SVC) Input Output Input Output Port VPI/VCI Port VPI/VCI Port VPI/VCI Port VPI/VCI 1 29 3 45 1 29 3 45 1 64 3 29 1 64 3 29 • Transfer data over newly established link 3 29 1 64 3 29 1 64 1 4 1 C 2 3 3 3 2 Input Output Input Output 2 1 Port VPI/VCI Port VPI/VCI Port VPI/VCI Port VPI/VCI 4 1 45 2 16 1 16 2 43 2 52 1 29 D 1 64 3 29 1 64 3 29 3 29 1 64 3 29 1 64

  32. UNISignaling UNISignaling NNISignaling B Switched Virtual Circuit (SVC) Input Output Input Output Port VPI/VCI Port VPI/VCI Port VPI/VCI Port VPI/VCI 1 29 3 45 1 64 3 29 1 64 3 29 A • Dynamically tear down connectionsvia signaling 3 29 1 64 3 29 1 64 1 4 1 C 2 3 3 3 2 Input Output Input Output 2 1 Port VPI/VCI Port VPI/VCI Port VPI/VCI Port VPI/VCI 4 2 52 1 29 D 1 64 3 29 1 64 3 29 3 29 1 64 3 29 1 64

  33. UNISignaling UNISignaling NNISignaling B Soft PVC Input Output Input Output Port VPI/VCI Port VPI/VCI Port VPI/VCI Port VPI/VCI 1 29 3 45 1 29 3 45 1 64 3 29 1 64 3 29 • PVC established manually across UNI and dynamically across NNI A 3 29 1 64 3 29 1 64 1 C 3 1 Input Output Input Output 2 Port VPI/VCI Port VPI/VCI Port VPI/VCI Port VPI/VCI 1 16 2 43 2 52 1 29 D 1 64 3 29 1 64 3 29 3 29 1 64 3 29 1 64

  34. Agenda • Introduction • ATM Fundamentals • Rudimentary ATM Concepts • ATM Reference Model • ATM Adaptation Layer (AAL) • Traffic Management • ATM Transport Standards • Campus ATM Internetworking • Wrap Up

  35. ATM Reference Model • Physical layer • ATM layer • ATM adaptation layer • A day in the life of a cell

  36. ATM Reference Model ATM Adaptation Layer (AAL) ATM Layer Physical Layer

  37. ATM Reference Model Physical Layer ATM Adaptation Layer (AAL) Two Sublayers: • Transmission Convergence (TC) • Framing • HEC • Physical Media Dependent (PMD) • Physical media coding ATM Layer Physical Layer

  38. ATM Adaptation Layer (AAL) ATM Layer Physical Layer Physical Layer Framing DataRate(Mbps) Media Multi-ModeFiber Single-ModeFiber CoaxialCable UTP–5 UTP–3 STP DS1 E1 J2 1.5442.0486.23 (TP)(TP) DS3 E3 E4 4534139 X ATM25STS 1STS3c/STM1 25.651.8155 X STS 12c/STM44B/5B (TAXI)8B/10B(Fiberchannel) 622100155 = Standardized = Proposed/In Progress X

  39. ATM Reference Model ATM Layer ATM Adaptation Layer (AAL) • Cell header insertion/removal • Cell Relay • Multiplexes/demultiplexes cells of different connections ATM Layer Physical Layer

  40. ATM Layer Virtual Channel Connection (VCC) ATM Adaptation Layer (AAL) Virtual PathConnection (VPC) • Provides VPI/VCI values in header • Ensures that cells stay in the correct order UNI UNI ATM Layer NNI NNI VCSwitch VPSwitch VCSwitch Physical Layer VPI = 0VCI = 38 VPI = 12VCI = 44 VPI = 26VCI = 44 VPI = 0VCI = 36

  41. ATM Reference Model ATM Adaption Layer (AAL) ATM Adaptation Layer (AAL) Two Sublayers: • Convergence Sublayer (CS) • Segmentation and Reassembly (SAR) ATM Layer Physical Layer

  42. ATM Adaptation Layer (AAL) ATM Layer Physical Layer ATM Adaptation Layer—AAL AAL S A R AAL = QoS + SAR • CS—assigns different AAL’s/QoS for different traffic types • SAR—cell <-> packet C S

  43. ATM Adaptation Layer Class ServiceCategories Bit Rate ConnectionMode TimingConcern ApplicationExamples ATM Adaptation Layer (AAL) A AAL1 CBR(Constant) Connection-Oriented Yes • Bandwidth andthroughput guaranteed • Good for voice and video B AAL2 VBR(Variable)VBR-ATandVBR-NRT Connection-Oriented Yes • Best effort bandwidth and throughput • Good for live video,multimedia, LAN-to-LAN ATM Layer C AAL5 ABR(Available) Connection-Oriented No • Best effort withcongestion feedback • Reliable delivery of bursty traffic iflatency okay Physical Layer D AAL3/4 UBR(Un-specified) Connection-less No • No guarantee • For SMDS/LAN

  44. ATM Reference Model • Physical layer • ATM layer • ATM adaptation layer • A day in the life of a cell

  45. TCP Header App Data IP Header TCP Header App Data LLC IP Header TCP Header App Data QoS + LLC IP Header TCP Header App Data A Day in the Life of a Cell ATM Payload Processing TCP TCP Packet IP IP Datagram LLC/SNAP ConvergenceSublayer (CS) AAL Put in 48 Byte Cells—SAT into PDU SAR ATM Add 5 Byte Headers with VPI/VCI and CLP Transmission Convergence (STS, STM, DS) PHY Physical Media (MMF, SMF, STP, UDP,…

  46. ATM Switch ATM Layer Port 1 Port VPI VCI PHY ATM 1 2 37 2 1 51 Port 2 PHY ATM A Day in the Life of a Cell Traversing the Network AAL ATM PHY UNI VPI 2VCI 37 NNI ATM Switch ATM Layer Port 1 Port VPI VCI PHY ATM 1 1 51 2 3 39 VPI 3VCI 39 Port 2 AAL ATM PHY PHY ATM UNI Cisco Systems Confidential 0680_03F7_c3 46

  47. Agenda • Introduction • ATM Fundamentals • Rudimentary ATM Concepts • ATM Reference Model • ATM Adaptation Layer (AAL) • Traffic Management • ATM Transport Standards • Campus ATM Internetworking • Wrap Up

  48. AAL • AAL criteria • Traffic parameters • QoS parameters • The AAL’s • AAL1—CBR • AAL2—VBR • AAL3/4—UBR • AAL5—ABR

  49. Contract AAL Criteria Contract ATM Network Contract • Traffic Parameters • Peak cell rate • Sustainable cell rate • Maximum burst size • Minimum Cell Rate • Quality of Service • Delay • Cell loss

  50. AAL Criteria Traffic Parameters • Peak Cell Rate—PCR—Maximum data rate a connection can handle without losing data • Sustainable Cell Rate—SCR—Average ATM cell throughput the application is permitted • Maximum Burst Size—MBS—Size of themaximum burst of contiguous cells that can be transmitted • Minimum Cell Rate—MCR—Rate of anapplication’s ability to handle latency

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