Backplane Technology Overview
B k l     T h l      O    i
      for AdvancedTCA

  Hui Chen                       Theresienstr. 90
  Supervisor: Rainer Ohlendorf   80290 Munich
                                 Germany

  July, 13th 2007                www.lis.ei.tum.de




                                                 © Institute for
                                           Integrated Systems
Outline

Introduction to AdvancedTCA
Interconnect Protocols
I t        tP t     l
① Ethernet
② InfiniBand
③ StarFabric
④ PCI Express
⑤ RapidIO

Comparison of Interconnect Protocols
① Feature
② Protocol Efficiency
③ Effective Bandwidth
④ System Level Consideration

Conclusion
C   l i

               Hauptseminar am Lehrstuhl für Integrierte Systeme         © Institute for
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                             Hui Chen, July 13th 2007              Integrated Systems
What is AdvancedTCA ?
• AdvancedTCA (Advanced Telecom Computing Architecture)
    Standard chassis/ backplane solution for high-availability
    communications equipment
    Adopted in 2003


• AdvancedTCA Chassis




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                             Hui Chen, July 13th 2007              Integrated Systems
Base Spec of AdvancedTCA
• Board dimension
     1.2 inches in width
     280 mm deep, ~322 mm high


• Power supply & Cooling
     -48 V power feeds
     200 Watts per board
                                                               Board of AdvancedTCA




                                                     • Backplane architecture
                                                          Zone 1: P
                                                          Z    1 Power, MManagement   t
                                                          Zone 2: Data Transport Interface
                                                          Zone 3: User-defined I/O

    Backplane of AdvancedTCA
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                               Hui Chen, July 13th 2007               Integrated Systems
Data Transport Interface
• Base Interface: Dual Star
      Supports only Ethernet

• Fabric Interface: Dual Star/ Full Mesh
      Supports various protocols
      Max. 4 channels

                                                                (a) Dual Star configuration
• Dual Star
      Redundant switch: eliminates single point of
      failure
      Effective for large redundant systems

• F ll M h
  Full Mesh
      +) Higher data throughput
      -) Higher pins count & cost
      Effective for
      Eff ti f small systems
                       ll   t
                                                                (b) Full Mesh configuration

                 Hauptseminar am Lehrstuhl für Integrierte Systeme           © Institute for
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                               Hui Chen, July 13th 2007                Integrated Systems
Outline
Introduction to AdvancedTCA

Interconnect Protocols
①   Ethernet
②   InfiniBand
③   StarFabric
④   PCI Express
⑤   RapidIO

Comparison of Interconnect Protocols
① Feature
② Protocol Efficiency
③ Effective Bandwidth
④ System Level Consideration

Conclusion
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                            Hui Chen, July 13th 2007              Integrated Systems
Protocol ① ― Ethernet
• Application:
     Initial in Local Area Network
     Successful in backplane
     but defective in congestion management

• Congestion management
   PAUSE function: all data flows are paused when only
   one flow is congested
   → congestion spreading, when complex data p
          g        p     g,            p       paths

• Topology
   P2P connections: Ethernet Switch ↔ Endpoints                       Ethernet Topology


• Frame

     Header: large

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                               Hui Chen, July 13th 2007              Integrated Systems
Protocol ② ― InfiniBand ⑴
• Application                                                       Processor Node

     Initial in System Area Network
     now also i b k l
             l in backplane, chassis-to-chassis
                              h   i t h      i
     Supercomputer, Linux cluster


• Topology
     InfiniBand Switches + Channel Adapters
     HCA: Host Channel Adapter in processor node
     TCA: Target Channel Adapter in I/O node
                                                                    I/O Node
          HCA talks TCAs to enable remote
                                                                    InfiniBand Topology
          storage and connectivity


• Packet format


     Larger payload size than Ethernet

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                              Hui Chen, July 13th 2007                 Integrated Systems
Protocol ② ― InfiniBand ⑵
• Three   link widths                                       x1

  Links                x1       x4        x12               x4
  Data Rate (Gb/s)     2        8         24
                                                            x12


• Supports Quality of Service (QoS)
     QoS: a method to prioritize network traffic
           Ensures most important data gets thru the network as quickly as possible
           Defines traffic to many streams, streams to differentiated classes;
           reserves bandwidth to streams and classes




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                                 Hui Chen, July 13th 2007                Integrated Systems
Protocol ② ― InfiniBand ⑶
• Supports Quality of Service
     Thru 16 Virtual Lanes (VLs)
         Multiplex independent data streams
         → the same physical link
         Represent a set of send & receive
            p
         buffers in a port
         Each port: one management VL (VL15)
         & up to 15 data VLs
         Priorities

                  VL15 (highest)
                  VL14
                      …




                  VL0                                                Virtual Lanes



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                               Hui Chen, July 13th 2007               Integrated Systems
Protocol ③ ― StarFabric ⑴
• Application
     Backplane, chassis-to-chassis
     Embedded distributed processing
     (e.g. multiprocessor systems)


• Topology
     StarFabric Switch: six-port
         Connects other switches/ bridges
         Cascadable
     StarFabric Bridge                                       StarFabric Topology

         Translates other protocols (e.g. PCI) into
         StarFabric traffic
         St F b i t ffi


• Not scalable
     Operates only at 2 Gb/s
     O    t     l t Gb/

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                              Hui Chen, July 13th 2007               Integrated Systems
Protocol ③ ― StarFabric ⑵
• Packet format



• Supports Quality of Service
     7 classes of traffic
        asynchronous traffic (data)
        multicast
        …
        isochronous traffic (voice & video)


• Backwards compatible to PCI
     Converting a serial fabric to parallel PCI




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                               Hui Chen, July 13th 2007             Integrated Systems
Protocol ④ ― PCI Express ⑴
• Successor to PCI
     Backplane, chip-to-chip interconnect
     PC (e.g. Graphics cards)

• Topology
     Switches
     Multiple Endpoints: I/O devices
     Host Bridge
            To create an I/O hierarchy
                                                                       PCI Express Topology

• Six link widths:
    Links                 x1      x2       x4        x8    x16        x32
    Data Rate (Gb/s)      2       4         8        16    32         64



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                                Hui Chen, July 13th 2007                    Integrated Systems
Protocol ④ ― PCI Express ⑵
• Packet format



• Supports Quality of Service
     Thru
     Thr 8 Traffic Classes (TCs) & 8 Virt al Channels (VCs)
                                     Virtual
         Each port : up to 8 VCs. VC0 (lowest priority), VC7 (highest)
         TCs: differentiated services
         Each
         E h packet a TC t determine which VC b ff t d
                   k t TC: to d t     i hi h  buffer to drop packet i t
                                                                k t into
         TC/VC mapping:         ☺ TC[0:6]→VC0                TC7→VC[0:1]




                            An Example of TC/VC mapping
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                             Hui Chen, July 13th 2007                Integrated Systems
Protocol ⑤ ― RapidIO ⑴
• Application
     Backplane, chip-to-chip interconnect
     Embedded systems (e.g. DSPs)
     Networking (e.g. Carrier Cards)


•T
 Topology
     l
     A Switch, multiple Endpoints
     Large systems: one / more host processors
         For system exploration, initialization
                    exploration
         Monitors system-level activity
                                                                       RapidIO Topology

• Two link widths (x1 x4)
                  (x1,
       Links                              x1                      x4

       Data Rate (Gb/s)    1          2         2.5       4   8         10



                Hauptseminar am Lehrstuhl für Integrierte Systeme             © Institute for
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                               Hui Chen, July 13th 2007                 Integrated Systems
Protocol ⑤ ― RapidIO ⑵
• Packet format


     Header: smaller than Ethernet:
     1-byte source address ~ 28 Endpoints → sufficient for backplane applications
     Payload size: relatively small


• Supports Quality of Service
     Six logical flows: as prioritized classes




                 Hauptseminar am Lehrstuhl für Integrierte Systeme         © Institute for
                                                                                             16
                               Hui Chen, July 13th 2007              Integrated Systems
Outline
Introduction to AdvancedTCA
Interconnect Protocols
① Ethernet
② InfiniBand
③ StarFabric
④ PCI Express
⑤ RapidIO

Comparison of Interconnect Protocols
①   Feature
②   Protocol Efficiency
③   Effective Bandwidth
④   System Level Consideration

Conclusion
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                             Hui Chen, July 13th 2007              Integrated Systems
Comparison – Feature


Feature         GigE            InfiniBand       StarFabric    PCI Expr
                                                                   Expr.         RapidIO

Transport       PCB, Copper &   PCB, Copper &    PCB &         PCB, Copper &
Media           Fiber           Fiber                          Optical
                                                                                 PCB only
                                                 CAT5 cable
Scalable Link
                None            Yes              None          Yes               Yes
Widths

                                Encapsulated,    Yes,          Yes,              Yes,
PCI Migration   None            requires SW
                                  q              transparent
                                                      p        transparent
                                                                    p            requires SW

Max Signal
                1 Gbps          2 Gbps           2 Gbps        2 Gbps            2.5 Gbps
Channel Rate

      y
Max Payload
                1500 B tes
                     Bytes      4096 B t
                                     Bytes       128 B t
                                                     Bytes     4096 B t
                                                                    Bytes        256 B tes
                                                                                     Bytes
Size




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                                Hui Chen, July 13th 2007                Integrated Systems
Comparison – Protocol Efficiency
• Protocol Efficiency = Payload / Packet size
• Payload < ~500B : RapidIO, highest efficiency              smallest overhead
  Payload > ~500B : PCI Express, highest
                        Express




                 Hauptseminar am Lehrstuhl für Integrierte Systeme         © Institute for
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                               Hui Chen, July 13th 2007              Integrated Systems
Comparison – Effective Bandwidth
• Effective Bandwidth = Protocol efficiency × Bandwidth
• InfiniBand x4; PCIe x4; RapidIO 4x 2Gbps
• O
  Overall: Gi E l
       ll GigE, lowest
                     t




                Hauptseminar am Lehrstuhl für Integrierte Systeme         © Institute for
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                              Hui Chen, July 13th 2007              Integrated Systems
Comparison – System Level
• Quality of Service (QoS)

                          GigE
                          Gi E            InfiniBand
                                          I fi iB d         StarFabric
                                                            St F b i         PCI E
                                                                                 Expr.           RapidIO
                                                                                                 R idIO

    Prioritized Traffic
                          -               16                7                8                   6
    Classes




•P f
 Performance
                           GigE             InfiniBand          StarFabric       PCI Expr.        RapidIO

    Max Bandwidth for
    M B d idth f
                           1 Gbps           8 Gbps              2 Gbps           8 Gbps           10 Gbps
    AdvancedTCA, x4

    Latency                High             Medium              Medium           Low              Low
                           (~100 us)        (1.29-2.6 us)       (< 3 us)         (0.3-0.7 us)     (< 100 ns)




                  Hauptseminar am Lehrstuhl für Integrierte Systeme                          © Institute for
                                                                                                               21
                                   Hui Chen, July 13th 2007                            Integrated Systems
Outline
Introduction to AdvancedTCA
Interconnect Protocols
① Ethernet
② InfiniBand
③ StarFabric
④ PCI Express
⑤ RapidIO

Comparison of Interconnect Protocols
① Feature
② Protocol Efficiency
③ Effective Bandwidth
④ System Level Consideration

Conclusion
               Hauptseminar am Lehrstuhl für Integrierte Systeme         © Institute for
                                                                                           22
                             Hui Chen, July 13th 2007              Integrated Systems
Conclusion
• Low bandwidth backplane applications
      Ethernet                +) well understood, low risk
                              -) high overhead, hi h l
                               ) hi h     h d high latency
                              -) not scalable

• High bandwidth (tradeoffs of flexibility vs. latency, overhead)
    g            (                       y           y,         )
      InfiniBand and StarFabric
           Complex header: +) for complex routing
                           -) reduces effective bandwidth
      RapidIO
           Smaller packets: +) to lower latency
                            -) overhead: a higher percentage of the packet
                            -) reduces effective b d idth
                             ) d          ff ti bandwidth
      PCI Express
           Middle:            +) design goal: software transparency
                              -) constrains the protocol raises latency
                                                protocol,


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                               Hui Chen, July 13th 2007              Integrated Systems
Thank you for your attention !

               Any questions ?


                                                    Special thanks to:
                                                    Rainer Ohlendorf




Hauptseminar am Lehrstuhl für Integrierte Systeme           © Institute for
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              Hui Chen, July 13th 2007                Integrated Systems

Backplane Technology Overview for AdvancedTCA

  • 1.
    Backplane Technology Overview Bk l T h l O i for AdvancedTCA Hui Chen Theresienstr. 90 Supervisor: Rainer Ohlendorf 80290 Munich Germany July, 13th 2007 www.lis.ei.tum.de © Institute for Integrated Systems
  • 2.
    Outline Introduction to AdvancedTCA InterconnectProtocols I t tP t l ① Ethernet ② InfiniBand ③ StarFabric ④ PCI Express ⑤ RapidIO Comparison of Interconnect Protocols ① Feature ② Protocol Efficiency ③ Effective Bandwidth ④ System Level Consideration Conclusion C l i Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 2 Hui Chen, July 13th 2007 Integrated Systems
  • 3.
    What is AdvancedTCA ? • AdvancedTCA (AdvancedTelecom Computing Architecture) Standard chassis/ backplane solution for high-availability communications equipment Adopted in 2003 • AdvancedTCA Chassis Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 3 Hui Chen, July 13th 2007 Integrated Systems
  • 4.
    Base Spec of AdvancedTCA • Board dimension 1.2 inches in width 280 mm deep, ~322 mm high • Power supply & Cooling -48 V power feeds 200 Watts per board Board of AdvancedTCA • Backplane architecture Zone 1: P Z 1 Power, MManagement t Zone 2: Data Transport Interface Zone 3: User-defined I/O Backplane of AdvancedTCA Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 4 Hui Chen, July 13th 2007 Integrated Systems
  • 5.
    Data Transport Interface • Base Interface:Dual Star Supports only Ethernet • Fabric Interface: Dual Star/ Full Mesh Supports various protocols Max. 4 channels (a) Dual Star configuration • Dual Star Redundant switch: eliminates single point of failure Effective for large redundant systems • F ll M h Full Mesh +) Higher data throughput -) Higher pins count & cost Effective for Eff ti f small systems ll t (b) Full Mesh configuration Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 5 Hui Chen, July 13th 2007 Integrated Systems
  • 6.
    Outline Introduction to AdvancedTCA InterconnectProtocols ① Ethernet ② InfiniBand ③ StarFabric ④ PCI Express ⑤ RapidIO Comparison of Interconnect Protocols ① Feature ② Protocol Efficiency ③ Effective Bandwidth ④ System Level Consideration Conclusion Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 6 Hui Chen, July 13th 2007 Integrated Systems
  • 7.
    Protocol ① ― Ethernet •Application: Initial in Local Area Network Successful in backplane but defective in congestion management • Congestion management PAUSE function: all data flows are paused when only one flow is congested → congestion spreading, when complex data p g p g, p paths • Topology P2P connections: Ethernet Switch ↔ Endpoints Ethernet Topology • Frame Header: large Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 7 Hui Chen, July 13th 2007 Integrated Systems
  • 8.
    Protocol ② ― InfiniBand ⑴ •Application Processor Node Initial in System Area Network now also i b k l l in backplane, chassis-to-chassis h i t h i Supercomputer, Linux cluster • Topology InfiniBand Switches + Channel Adapters HCA: Host Channel Adapter in processor node TCA: Target Channel Adapter in I/O node I/O Node HCA talks TCAs to enable remote InfiniBand Topology storage and connectivity • Packet format Larger payload size than Ethernet Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 8 Hui Chen, July 13th 2007 Integrated Systems
  • 9.
    Protocol ② ― InfiniBand ⑵ •Three link widths x1 Links x1 x4 x12 x4 Data Rate (Gb/s) 2 8 24 x12 • Supports Quality of Service (QoS) QoS: a method to prioritize network traffic Ensures most important data gets thru the network as quickly as possible Defines traffic to many streams, streams to differentiated classes; reserves bandwidth to streams and classes Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 9 Hui Chen, July 13th 2007 Integrated Systems
  • 10.
    Protocol ② ― InfiniBand ⑶ •Supports Quality of Service Thru 16 Virtual Lanes (VLs) Multiplex independent data streams → the same physical link Represent a set of send & receive p buffers in a port Each port: one management VL (VL15) & up to 15 data VLs Priorities VL15 (highest) VL14 … VL0 Virtual Lanes Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 10 Hui Chen, July 13th 2007 Integrated Systems
  • 11.
    Protocol ③ ― StarFabric ⑴ •Application Backplane, chassis-to-chassis Embedded distributed processing (e.g. multiprocessor systems) • Topology StarFabric Switch: six-port Connects other switches/ bridges Cascadable StarFabric Bridge StarFabric Topology Translates other protocols (e.g. PCI) into StarFabric traffic St F b i t ffi • Not scalable Operates only at 2 Gb/s O t l t Gb/ Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 11 Hui Chen, July 13th 2007 Integrated Systems
  • 12.
    Protocol ③ ― StarFabric ⑵ •Packet format • Supports Quality of Service 7 classes of traffic asynchronous traffic (data) multicast … isochronous traffic (voice & video) • Backwards compatible to PCI Converting a serial fabric to parallel PCI Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 12 Hui Chen, July 13th 2007 Integrated Systems
  • 13.
    Protocol ④ ― PCI Express ⑴ •Successor to PCI Backplane, chip-to-chip interconnect PC (e.g. Graphics cards) • Topology Switches Multiple Endpoints: I/O devices Host Bridge To create an I/O hierarchy PCI Express Topology • Six link widths: Links x1 x2 x4 x8 x16 x32 Data Rate (Gb/s) 2 4 8 16 32 64 Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 13 Hui Chen, July 13th 2007 Integrated Systems
  • 14.
    Protocol ④ ― PCI Express ⑵ •Packet format • Supports Quality of Service Thru Thr 8 Traffic Classes (TCs) & 8 Virt al Channels (VCs) Virtual Each port : up to 8 VCs. VC0 (lowest priority), VC7 (highest) TCs: differentiated services Each E h packet a TC t determine which VC b ff t d k t TC: to d t i hi h buffer to drop packet i t k t into TC/VC mapping: ☺ TC[0:6]→VC0 TC7→VC[0:1] An Example of TC/VC mapping Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 14 Hui Chen, July 13th 2007 Integrated Systems
  • 15.
    Protocol ⑤ ― RapidIO ⑴ •Application Backplane, chip-to-chip interconnect Embedded systems (e.g. DSPs) Networking (e.g. Carrier Cards) •T Topology l A Switch, multiple Endpoints Large systems: one / more host processors For system exploration, initialization exploration Monitors system-level activity RapidIO Topology • Two link widths (x1 x4) (x1, Links x1 x4 Data Rate (Gb/s) 1 2 2.5 4 8 10 Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 15 Hui Chen, July 13th 2007 Integrated Systems
  • 16.
    Protocol ⑤ ― RapidIO ⑵ •Packet format Header: smaller than Ethernet: 1-byte source address ~ 28 Endpoints → sufficient for backplane applications Payload size: relatively small • Supports Quality of Service Six logical flows: as prioritized classes Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 16 Hui Chen, July 13th 2007 Integrated Systems
  • 17.
    Outline Introduction to AdvancedTCA InterconnectProtocols ① Ethernet ② InfiniBand ③ StarFabric ④ PCI Express ⑤ RapidIO Comparison of Interconnect Protocols ① Feature ② Protocol Efficiency ③ Effective Bandwidth ④ System Level Consideration Conclusion Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 17 Hui Chen, July 13th 2007 Integrated Systems
  • 18.
    Comparison – Feature Feature GigE InfiniBand StarFabric PCI Expr Expr. RapidIO Transport PCB, Copper & PCB, Copper & PCB & PCB, Copper & Media Fiber Fiber Optical PCB only CAT5 cable Scalable Link None Yes None Yes Yes Widths Encapsulated, Yes, Yes, Yes, PCI Migration None requires SW q transparent p transparent p requires SW Max Signal 1 Gbps 2 Gbps 2 Gbps 2 Gbps 2.5 Gbps Channel Rate y Max Payload 1500 B tes Bytes 4096 B t Bytes 128 B t Bytes 4096 B t Bytes 256 B tes Bytes Size Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 18 Hui Chen, July 13th 2007 Integrated Systems
  • 19.
    Comparison – Protocol Efficiency • ProtocolEfficiency = Payload / Packet size • Payload < ~500B : RapidIO, highest efficiency smallest overhead Payload > ~500B : PCI Express, highest Express Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 19 Hui Chen, July 13th 2007 Integrated Systems
  • 20.
    Comparison – Effective Bandwidth • EffectiveBandwidth = Protocol efficiency × Bandwidth • InfiniBand x4; PCIe x4; RapidIO 4x 2Gbps • O Overall: Gi E l ll GigE, lowest t Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 20 Hui Chen, July 13th 2007 Integrated Systems
  • 21.
    Comparison – System Level • Qualityof Service (QoS) GigE Gi E InfiniBand I fi iB d StarFabric St F b i PCI E Expr. RapidIO R idIO Prioritized Traffic - 16 7 8 6 Classes •P f Performance GigE InfiniBand StarFabric PCI Expr. RapidIO Max Bandwidth for M B d idth f 1 Gbps 8 Gbps 2 Gbps 8 Gbps 10 Gbps AdvancedTCA, x4 Latency High Medium Medium Low Low (~100 us) (1.29-2.6 us) (< 3 us) (0.3-0.7 us) (< 100 ns) Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 21 Hui Chen, July 13th 2007 Integrated Systems
  • 22.
    Outline Introduction to AdvancedTCA InterconnectProtocols ① Ethernet ② InfiniBand ③ StarFabric ④ PCI Express ⑤ RapidIO Comparison of Interconnect Protocols ① Feature ② Protocol Efficiency ③ Effective Bandwidth ④ System Level Consideration Conclusion Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 22 Hui Chen, July 13th 2007 Integrated Systems
  • 23.
    Conclusion • Low bandwidthbackplane applications Ethernet +) well understood, low risk -) high overhead, hi h l ) hi h h d high latency -) not scalable • High bandwidth (tradeoffs of flexibility vs. latency, overhead) g ( y y, ) InfiniBand and StarFabric Complex header: +) for complex routing -) reduces effective bandwidth RapidIO Smaller packets: +) to lower latency -) overhead: a higher percentage of the packet -) reduces effective b d idth ) d ff ti bandwidth PCI Express Middle: +) design goal: software transparency -) constrains the protocol raises latency protocol, Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 23 Hui Chen, July 13th 2007 Integrated Systems
  • 24.
    Thank you foryour attention ! Any questions ? Special thanks to: Rainer Ohlendorf Hauptseminar am Lehrstuhl für Integrierte Systeme © Institute for 24 Hui Chen, July 13th 2007 Integrated Systems