Express Logic’s NetX™ Achieves Top Transfer Speed on Xilinx MicroBlaze
ESC-Silicon Valley, San Jose, CA(April 26, 2010)

Express Logic, Inc., the worldwide leader in royalty-free real-time operating systems (RTOS), today announced that its NetX™ TCP/IP networking stack has achieved the highest reported network packet throughput on the Xilinx MicroBlaze soft-core processor. NetX is a small, fast network stack designed for embedded applications. With extremely low overhead, NetX provides zero-copy packet transfers to achieve very high throughput. Running on the Xilinx MicroBlaze processor at 100MHz, NetX delivered outstanding packet performance, running a set of performance tests based on the Iperf open-source network transfer rate measurement tool.

Express Logic ran Iperf throughput tests for both TCP and UDP transfers, both Transmit (TX) and Receive (RX), with packet sizes of 1,500 and 9,000 bytes. All tests were run on the Xilinx MicroBlaze platform, where NetX achieved transfer rates between 187 and 926 megabits per second (Mbps), depending on the particular test that was run. The transfer rates vary between TCP and UDP because TCP (Transmission Control Protocol) checks that packets are correctly sent to the receiver whereas UDP (User Datagram Protocol) sends packets without any checks. UDP typically is used in LANs where data integrity can be assumed or where occasional data loss is considered inconsequential. All results are stated in Mbps (higher is better):

  MTU 1500 MTU 9000











Iperf is a commonly used network testing tool that can create TCP and UDP data streams and measure the throughput of a network carrying them. Iperf is supported by the National Laboratory for Applied Network Research. When testing UDP capacity, Iperf allows the user to specify the datagram size and provides results for throughput and the packet loss. When used for testing TCP capacity, Iperf measures the throughput of the payload.

“Express Logic’s NetX is a high performance networking stack and has demonstrated impressive results with the latest Spartan-6 (SP605) FPGA Embedded kits, leveraging the high performance hard memory controllers and Tri-mode EMAC IP,” said Brent Przybus, Director of Platform Solutions, Xilinx. “NetX is a great fit for MicroBlaze developers looking for optimum network throughput. What’s more, NetX also is small in memory footprint, saving valuable FPGA BRAMs for other use.”

NetX is a complete TCP/IP dual stack, with TCP, IP, UDP, ARP, RARP, ICMP, and IGMP protocol support. NetX also includes multiple applications, namely AutoIP, DHCP, DNS, FTP, HTTP, NAT, POP3, PPP, SMTP, SNMP, SNTP, Telnet, TFTP, and a BSD-compatible socket layer.

IEEE Paper by Sony Applauds NetX High Throughput

Basic UDP packets pass through NetX without any copying and without any system context switches. Many commercial network stacks process all packets received within a system thread thereby adding a context switch to the packet overhead. In NetX, simple UDP packets are delivered directly to waiting threads. NetX achieves its high performance as a result of its zero-copy, piconet architecture, which enables processing to be scaled to eliminate excessive overhead not needed for a particular application. Last year, NetX was featured in an IEEE technical paper by Sony engineers that described its achievement of “near wire speed”. See:

“NetX is central to our product strategy, and these performance measurements show why many of our customers choose it as their network stack,” said William E. Lamie, president fo Express Logic. “NetX was designed in-house, from the ground up, to complement ThreadX and to provide the ultimate in network performance and functionality for processors like the Xilinx MicroBlaze. These outstanding numbers support our belief that NetX is the fastest TCP/IP stack currently available for embedded applications.”

Shipping and Availability

NetX is available for Xilinx MicroBlaze at license prices starting at $12,500, with full source code, royalty-free.

About Express Logic and ThreadX

Headquartered in San Diego, CA, Express Logic, Inc., offers the industry’s most advanced run-time solutions for deeply embedded applications, including the popular ThreadX® RTOS, the high-performance NetX™ and NetX Duo™ TCP/IP stacks, the FileX® embedded FAT-compatible file system, the USBX™ Host/Device USB protocol stack, and the GUIX™ embedded graphical user interface development toolkit. Most products from Express Logic include full source-code and all are available free of run-time royalties. For more information about Express Logic solutions, please visit, call 1-888-THREADX, or email inquiries to

For More Information Contact:

Michael May
VP of Marketing
Express Logic, Inc.
Tel: (858) 613-6640 ext.207

Angie Hatfield
Media Relations
Hughes Communications, Inc.
(425) 941-2895
Cell: (425) 941-2895