DESIGN VIEW is the summary of the complete DESIGN SOLUTION contributed article, which begins on Page 2.
Current parallel backplane technologies are rapidly being replaced with advanced serial-I/O-based solutions. Two such open standards include PCI Express Base and Advanced Switching (AS). These new technologies recognize the prevalence and widespread use of legacy software yet offer advanced features.
Possessing full code compatibility with PCI/PCI-X-based software, PCI Express technology is being deployed in fabrics as well as in host and I/O subsystems. With support for nontransparent bridging, used in PCI for many years, PCI Express solutions can create complex multihosted designs.
When solutions based on AS—including its full physical and data-link layer compatibility with PCI Express Base and its advanced features—become available, high-end designs will migrate to a mixed PCI Express/AS solution. Host and I/O subsystems will continue to run legacy PCI Express/PCI code, and AS will operate as the system switching fabric.
Because PCI Express Base and AS have divergent transaction layers, these switches/bridges are necessary to ensure compatibility with both standards. Each of the switch's interfaces must ensure compatibility with both standards. It's crucial that the switch provide complete protocol interoperability including, but not limited to, translation of routing techniques, enumeration of PCI Express subsystems across an AS fabric, queue management, and the ability to ensure transaction ordering to prevent deadlock.
This article investigates how to intertwine the two technologies via PI-8 switching devices. Using these switches will ensure proper translation of routing methods and provide system configuration, buffer-management techniques, and a transaction ordering process to bridge the different methodologies of each standard.
Full article begins on Page 2