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INFINIBAND<br />Presented By- <br />Shekhar Kumar<br /> 074, CS-’B’<br />Guided By- Latha R. Nair<br />

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Contents<br />Introduction<br />I/O Architectures- Fabric vs Bus<br />Technical Overview<br />InfiniBand Layers<br />InfiniBand Architecture<br />Advantages & Drawbacks<br />Markets<br />Conclusion<br />References<br />

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Introduction<br /><ul><li>A switch-based serial I/O interconnect architecture

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Operates at a base speed of 2.5 Gb/s or 10 Gb/s in each direction (per port)

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Provides both QoS (Quality of Service) and RAS (Reliability, Availability and Serviceability)

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Used in high performance computing and data centres</li></li></ul><li>I/O Architectures- Fabric vs Bus<br />

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I/O Architectures Contd…<br />Shared Bus Architecture<br />CPU<br />System Memory<br />System Controller<br />I/O Controller<br />PCI to PCI Bridge<br />PCI to PCI Bridge<br />I/O Controller<br />I/O Controller<br />I/O Controller<br />I/O Controller<br />

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I/O Architectures Contd…<br />Switched Fabric Architecture<br />

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Technical Overview<br />Switch-based point-to-point interconnect architecture<br />Each individual link is based on a four-wire 2.5Gb/s bidirectional connection.<br />Architecture defines a layered hardware protocol (Physical, Link, Network, Transport Layers) as well as a software layer<br />Each link can support multiple transport services for reliability<br />

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InfiniBand Feature Set<br />Layered Protocol- Physical, Link, Network, Transport, Upper Layers<br />Packet based communication<br />Quality Of Service<br />Three link speeds<br />1X- 2.5 Gb/s, 4 Wire<br />4X- 10 Gb/s, 16 Wire<br />12X- 30 Gb/s, 48 Wire<br />PCB, Copper and Fiber cable interconnect<br />Multicast and Unicast support<br />

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InfiniBand Layers<br />

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InfiniBand LayersContd…<br />Physical Layer<br />Defines both electrical and mechanical characteristics for the system<br />Includes cables and receptables for fibre and copper media, backplane connectors<br />Defines three link speeds, 1X,4X,12X<br />Each individual link is a 4-wire differential connection that provides a full duplex connection at 2.5 Gb/s<br />

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InfiniBand Layers Contd…<br />2) Link Layer<br />Encompasses packet layout, point-to-point operations, and switching within a local subnet<br />Packets- Two types: Management and Data packets<br />Management Packets- Used for link configuration and maintenance<br />Data Packets- Carry up to 4k bytes of a transaction payload<br />Switching- Devices within a subnet have a 16-bit Local ID assigned by the subnet manager. This LID is used for addressing.<br />

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InfiniBand LayersContd…<br />Link Layer<br />QoS- supported through virtual lanes(VL)<br /><ul><li> VLs are separate logical communication links which share a single physical link</li></ul>Data Integrity<br /><ul><li>Two CRCs per packet, Variant CRC and Invariant CRC

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16-bit VCRC includes all fields in the packet and is recalculated at each hop

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32-bit ICRC covers only the fields that do not change from hop to hop</li></li></ul><li>InfiniBand LayersContd…<br />Network Layer<br />Handles routing of packets from one subnet to another(within a subnet a network layer is not required)<br />Packets contain a global route header(GRH)<br />GRH contains the 128-bit IPv6 address<br />Transport Layer<br />Responsible for in-order packet delivery, channel multiplexing and transport services<br />Also handles transaction data segmentation when sending, and reassembly when receiving <br />

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InfiniBand Architecture<br />

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InfiniBand ArchitectureContd…<br />Defines multiple devices for system communication: channel adapter, switch, router, and a subnet manager<br />At least one channel adapter is required for each end node<br />Subnet Manager sets up and maintains link<br />Channel adapters and switches contains Subnet Management Agent(SMA) for handling communication with the subnet manager<br />

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Channel Adapters<br />Connects InfiniBand to other devices<br />Two types: Host Channel adapter(HCA) and Target Channel Adapter(TCA)<br />HCA- Provides interface to a host device and supports all software verbs defined by InfiniBand<br />TCA- Provides connection to an I/O device from InfiniBand with a subset of HCA features necessary for specific operations of each device<br />

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Switches and Routers<br />

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Switches and RoutersContd…<br />Switch<br /><ul><li>Contains more than one InfiniBand port and forwards packets from one of its port to another based on the LID

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Can be configured to forward either unicast packets or multicast packets

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Can consume or generate management packets</li></ul>Router<br /><ul><li>Forwards packets from one subnet to another without consuming or generating packets

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Reads the Global Route Header to forward the packet based on IPv6 address</li></li></ul><li>Advantages<br />Superior performance<br />Low-latency<br />High-efficiency<br />Fabric consolidation and low energy usage<br />Reliable, stable connections<br />Data Integrity<br />Highly interoperable environment<br />

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Drawbacks<br />Complex in design<br />Few platforms supports it as yet<br />Bleeding edge, for now, so users will need to perform extensive testing<br />

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Markets<br />Application Clustering<br />Inter-Processor Communication(IPC)<br />Storage Area Networks<br />

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CONCLUSION<br />Greater processor performance<br />Supports RAS<br />Works both in-the-box and enables Bandwidth Out of the Box<br />Supports scalability<br />

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REFERENCES<br />InfiniBandTrade Association www.infinibandta.org <br />InfiniBandNetwork Architecture, MindShare, Inc. By Tom Shanley<br />InfiniBand Architecture, Development and Deployment: A strategic guide to server I/O solutions By William T. Futral<br />Qos in InfiniBandSubnetworks: <br />Alfaro,F.J.; Sanchez, J.L.; Duato, J.; Department de Informatica, Univ. de Castilla-La Mancha, Albacete, Spain<br />

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THANK YOU<br />

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Queries<br />???<br />