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HyperTransport networking extensions unveiled

By Dennis Sellers
Macworld MAY 5, 2002 5:00 pm PDT

The HyperTransport Technology Consortium, of which Apple is a member, was founded to develop, promote and manage specifications of the HyperTransport I/O link. The group today announced new networking extensions to address the “high-performance” demands of networking and telecommunication applications.

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HyperTransport complements externally visible bus standards like the Peripheral Component Interconnect (PCI), as well as emerging technologies like InfiniBand and 10GB Ethernet. Although initially developed for high-performance personal computer and server platforms, the technology is also gaining momentum in networking and communications devices, embedded applications and other non-personal computer devices. Multiple products integrating support for HyperTransport technology are in development to support desktop and notebook computers, workstations and servers and Internet communication devices.

The new HyperTransport networking extensions are designed to ensure interoperability with existing HyperTransport products and complement externally visible bus standards like PCI, as well as emerging technologies like InfiniBand and Gigabit Ethernet. The HyperTransport networking extensions were developed by the consortium’s Technical Working Group to enhance control plane, data plane and look aside applications. The new networking features include: a message passing protocol for larger packet sizes, an error recovery protocol, support for 64-bit addresses, 16 additional streaming and dedicated virtual channels, greatly increased concurrency support, a standardized HyperTransport switching function and direct peer-to-peer transfer.

“These newly added networking extensions reduce complexity, increase efficiency and enhance the overall functionality of HyperTransport I/O specification,” said Brian Holden, chairperson of the HyperTransport Technology Consortium Technical Working Group and principal engineer for PMC-Sierra’s MIPS Processor Division.

According to the HyperTransport Technology Consortium, key networking enhancements include:

  • The addition of a message passing protocol enables HyperTransport technology to stream sequences of packets to a given address;
  • The addition of an error handling protocol enables the HyperTransport specification to detect and recover from errors, which increases the reliability and availability of the connection;
  • The optional increase of the supported addressing from 40-bit to 64-bit;
  • The addition of 16 streaming point-to-point flow controlled virtual channels that also enable support of millions of end-to-end flow controlled virtual channels;
  • Increased support for concurrent host transactions further improves the flexibility and performance of the HyperTransport specification by allowing over 1,000 transactions to be simultaneously outstanding;
  • The addition of support for direct peer-to-peer transfers increases efficiency by allowing data transfers to occur between non-host nodes without requiring a host reflection;
  • The formalization of the description of existing HyperTransport hubs and switches clearly defines each within the standard and provides a clear roadmap for each application.
  • The new HyperTransport networking extensions are planned to be available in the second half of 2002.

    • For more info on HyperTransport see our July 30, Aug. 6, and Aug. 8 articles.