InfiniBand offers to boost bus speeds

Server I/O technologies, particularly the PCI bus, have not kept up with the tremendous cost/performance improvements of processor, memory, storage and other related computer technologies.

InfiniBand is a new architecture designed to ease data traffic congestion among hardware devices, and is seen as a successor to PCI bus architecture.

The InfiniBand standard was initiated by the InfiniBand Trade Association, which includes Compaq, Dell, Intel, Microsoft and Sun. InfiniBand 1.0 is the first version of this new standard, which enables servers, remote storage and other network devices to be attached in a central fabric of switches and links. The new architecture improves system performance, reliability and availability. It also increases the independent scalability of fabric elements.

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Links at 2.5G bit/sec

With channel-based links operating at 2.5G bit/sec, InfiniBand-enabled servers will be better equipped to meet the demands of data centers. With the InfiniBand architecture, server, storage and network nodes connect as peers through the central InfiniBand fabric. The architecture is designed around a point-to-point, switched I/O fabric, where end-node devices - from simple, inexpensive I/O devices such as single- chip Fibre Channel or Ethernet adapters to much more complex host computers - are connected by cascaded switch devices.

The InfiniBand architecture supports two predominant environments, with bandwidth, distance and cost considerations appropriate for these environments: module-to-module computer systems that support I/O module add-in slots; and chassis-to-chassis interconnecting computers, external storage systems and external LAN/WAN access devices in data center environments.

InfiniBand can support bandwidths greater than prevailing I/O media such as SCSI, Fibre Channel and Ethernet. It uses IPv6 headers, which support efficient connections between InfiniBand architecture fabrics and traditional Internet and intranet infrastructures.

One of the more significant changes InfiniBand will bring is the removal of the I/O complex from the server. By replacing the bus architecture with InfiniBand technology, a server has the ability to remove I/O from the server chassis, creating greater server density, and allowing for a more flexible and scalable data center, as independent fabric nodes may be added as needed.

InfiniBand-enabled servers need to connect seamlessly into existing Ethernet LANs and Fibre Channel-based storage networks, unlike a server today, which connects directly to a LAN, a storage-area network (SAN), and sometimes to an Interprocess Communication network, through an I/O subsystem dedicated to each server/appliance.

This dedicated I/O subsystem consists of potentially redundant PCI buses, network interface cards and host bus adapters. The InfiniBand architecture was created to address PCI's inability to scale economically.

To facilitate the acceptance of InfiniBand technology, vendors are addressing these key infrastructure issues by applying InfiniBand in a nondisruptive manner to existing applications, management frameworks and network infrastructures. A new tier will be inserted between next-generation InfiniBand-enabled servers and SAN/LAN infrastructures. This tier will be composed of intelligent switches that will interconnect servers (application appliances), network modules (routers) and storage modules (high-end storage appliances).

System-area networks

InfiniBand-based system-area networks address the growing need for advancements and innovation in the areas of clustering and high-bandwidth network and storage connectivity. If InfiniBand becomes the major system-area network fabric in data centers, larger InfiniBand switches with increasing degrees of intelligence will begin to emerge. This development will radically improve communications in the data center and the ability to store and access data with greater reliability and manageability.

King is vice president of marketing at InfiniCon Systems. He can be reached at bking@infiniconsys.com

InfiniBand Trade Association

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