The PXH840 Gen3 PCI Express NTB Host Adapter is our high performance optical interface to external processor subsystems. Based on Broadcom® Gen3 PCI Express bridging architecture and Samtec PCIe FireFly® optical engine, the PXH840 host adapter provides advanced features for non-transparent bridging (NTB) over long distance PCIe.

For high performance application developers, the PXH840 host adapter combines 128 GT/s performance with an application to application latency starting at 0.54 microseconds. Inter-processor communication benefits from the high throughput and low latency. Using the latest SmartIO technology software from Dolphin, applications can now access PCIe devices located in computers up to 100 metres way as if they was attached to the local system.

The PXH840 performs both Remote Direct Memory Access (RDMA) and Programmed IO (PIO) transfers, effectively supporting both large and small data packets. RDMA transfers result in efficient larger packet transfers and processor off-load exceeding 11 Gigabytes per second. PIO transfers optimize small packet transfers at the lowest latency. The combination of RDMA and PIO creates a highly potent data transfer system.

Dolphin’s software suite takes advantage of PCI Express’ RDMA and PIO data transfer scheme. Delivering a complete deployment environment for customized and standardized applications. The suite includes a Shared-Memory Cluster Interconnect (SISCI) API as well as a TCP/IP driver and SuperSockets software. The SISCI API is a robust and powerful shared memory programming environment.

The optimized TCP/IP driver and SuperSockets™ software remove traditional networking bottlenecks, allowing standard IP and sockets applications to take advantage of the high performance PCI Express interconnect without modification. The overall framework is designed for rapid development of inter-processor communication systems.

The PXH840 card comes with a full license to the Dolphin eXpressWare software. The PXH842 Gen3 Adapter card does not include any software license and is well suited for high performance Transparent IO Expansion applications. The PXH840 card is fully supported in eXpressWare 5.5.0 and newer.

Supported topologies

Using the PXH840 card, you can connect two systems using PCIe Gen3 x4, x8 or x16 depending on the throughput requirements. You can also connect 3 systems using a x8 cable between each system.

Variants

The card is available in several variants with reduced number of FireFly optical modules mounted. The maximum performance and supported topologies for these cards will vary. Details can be found in the following table:

PXH84x NTB Host card variants

Part Number	Installed FireFly devices	Supported PCIe configuration	Required MPO Patch Fiber Cable
PXH840	Two x8	x16, Two x8	Two 24 strand
PXH841	One x8	x8	One 24 strand
PXH843	Two x4	x8, Two x4	Two 12 strand
PXH844	One x4	x4	One 12 strand

 

Fiber MPO Patch Cables

The PXH84x cards are carefully designed for maximum cable length and supports fiber cables up to 100 meter optical cables. The x8 FireFly device configuration requires two MPO female, 24 strand, OM3 50/125, Key up - Key up (Type C) cables. The x4 FireFly device configuration requires two MPO female, 12 strand, OM3 50/125, Key up - Key up (Type B) cables.

Features

• PCI Express® 3.0 compliant - 8.0 GT/s per lane
• Slot compliant with Gen1 and Gen2 PCI Express
• Samtec FireFly optical engine
• MTP connectors
• Four x4 Gen3 PCI Express cable ports that can be configured as:
  • One - x16 PCI Express port
  • Two - x8 PCI Express ports
• Two NTB ports max
• RDMA support through PIO and DMA
• Clock isolation support
• Non-transparent bridging to cabled PCI Express systems
• Low profile PCI Express form factor
• EEPROM for custom system configuration
• Link status LEDs through face plate

Performance