Fredy's SDN/OpenStack Blog Network performance in the SDN age


Welcome to Fredy Neeser’s weblog on networking and more!

In my blog, I will address various issues and findings regarding open-source and networking technologies, including network virtualization, SDN and OpenStack.

I decided to start my own technical blog to facilitate interactions with open-source communities.

Personal Information

I live with my family near Zurich, Switzerland. In my free time, I enjoy outdoor activities including jogging, hiking and skiing. Also, I’m passionate about music and love to accompany our local gospel choir “mim chor & band” with my Warwick bass guitar.

Professional Information

I am working as a Research Staff Member at the IBM Zurich Research Lab.

My professional life started in digital signal processing and coding. I received my Ph.D. in electrical engineering from ETH Zurich in 1993. After joining IBM in 1994, I designed digital signal processing algorithms for the V.34 (33.6 kbps) and V.90 (56 kbps) voiceband modems in ThinkPad notebooks. I received two IBM Outstanding Technical Achievement Awards for my work on modems. In my next project, I contributed to the design of a VLIW DSP by developing features for channel coding and filtering, and by creating a cycle-accurate DSP simulator.

In 2003, my interests shifted towards high-speed interconnects and datacenter networking. I contributed to Remote Direct Memory Access (RDMA) APIs and Soft-RDMA/iWARP, a Linux TCP kernel-sockets based software implementation of IETF’s iWARP RDMA stack, which achieved single-connection-single-core throughputs better than 6 Gb/s.

Since 2010, I worked on the design, modeling and optimization of a chipset for a 100 Gb/s Converged Enhanced Ethernet (CEE) fabric, including flow and congestion control. The chipset included a hub chip with a transport layer that enables high-performance packet-by-packet multipath while maintaining in-order frame transfers for TCP. This work involved the modeling and optimization of an edge-to-edge (ETE) flow control protocol.

For low latency forwarding, I optimized speculative transmission techniques by ensuring robustness through automatic transitions between speculation and buffer reservation. To ensure a faithful hardware representation, I created detailed C++ models on top of the Omnest++ network simulation framework, including modules for CEE, the transport layer and an interconnection network with integrated switching. This enabled an accurate performance prediction during the design of the chipset. I co-authored several papers associated with this work.

In 2014, my professional activities shifted back towards open-source networking; my current interests include the performance of scalable and/or lossless fabrics, overlays, network virtualization, and offloading technologies such as RDMA.


The content on this site is my own and does not necessarily represent the views, opinions or positions of my employer or any of its divisions or subsidiaries. This is a personal blog, not a corporate blog. The content published here is neither reviewed nor approved by my employer.

Contact Information

I can be reached at fredy dot neeser at solnet dot ch.


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