Issue No.01 - January/February (2005 vol.25)
Venkata Krishnan , Stargen
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/MM.2005.17
The PCI Express Advanced Switching Interconnect architecture includes status-based flow control (SBFC), a localized congestion-control mechanism that aims to alleviate the effects of transient congestion. The SBFC scheme suffices for handling persistent congestion in single-stage switch fabrics and complements traditional congestion management schemes in larger switch fabrics. There is little doubt that PCI Express is poised to succeed PCI as the next-generation chip interconnect (http://www.pcisig.com/specifications/pciexpress). Of PCI Express's many advantages, perhaps the greatest is that it addresses PCI's major inadequacies, yet enforces strict compatibility with PCI legacy systems. Consequently, the reams of software designed for PCI will operate seamlessly in a PCI Express world. To provide that degree of PCI compatibility, however, a PCI Express fabric must span a single global address space. With no notion of a system boundary, a PCI Express fabric is, by definition, a single system, within which multiple hosts cannot share a fabric. Having all communication under a single host's control makes PCI Express ill suited for multiprocessing and peer-to-peer communication.
Venkata Krishnan, "Localized Congestion Control in Advanced Switching Interconnects", IEEE Micro, vol.25, no. 1, pp. 10-18, January/February 2005, doi:10.1109/MM.2005.17