The Discrepancy of the Megaflow Cache in OVS, with Levente Csikor and Gabor Retvari from Budapest University of Technology and Economics

VMware Research High Bits is a podcast coming soon from VMware's research group. This episode is a sneak preview of episode 1, with Lalith Suresh. Lalith is a researcher in the VMware Research Group who specializes in measurement, design, and implementation of large-scale networked and distributed systems. Last year, Lalith published a blog entry with advice on how to build software systems for research, and then he followed up with a video with more details. This episode interviews Lalith to learn more about his approach to building research systems. To learn more about Lalith's work, visit his VMware Research webpage or his personal blog Comfortably Geek, where you can also find his contact information. VMware Research High Bits is produced by Ben Pfaff. The bumper sound in this episode is Ben biting into an apple.

Bruce Davie and Larry Peterson are the authors of the Systems Approach series of computer networking textbooks. Mark Twain has been called the greatest humorist the United States has produced and the father of American literature. This episode, the first collaboration among these celebrated authors, incorporates elements of the works of both [1, 2]. For more information on the Systems Approach series, visit systemsapproach.org or follow the series on substack as systemsapproach or Twitter as and @SystemsAppr. On Twitter, you can find Bruce as @_drbruced, Larry as @_llpete, and Mark as @MarkTwain. Bruce and Larry were previously featured in Episode 73: Computer Networks: A Systems Approach. OVS Orbit is produced by Ben Pfaff. The intro music in this episode is Drive, featuring cdk and DarrylJ, copyright 2013, 2016 by Alex. The outro music is Space Bazooka featuring Doxen Zsigmond, copyright 2013 by Kirkoid. Fanfares et Simphonies by Jean-Joseph Mouret, performed by Jean-Marie Leclair, dir. Jean-François Paillard, downloaded via imslp.org, is licensed under Creative Commons Zero 1.0 - Non-PD US. The scratch sound effect by Stumber was downloaded via freesound.org and licensed under Creative Common Attribution 3.0 Unported (CC BY 3.0). The episode as a whole is licensed as Creative Commons Attribution 3.0 Unported (CC BY 3.0).

Bruce Davie and Larry Peterson talk about their Systems Approach series of books on computer networking. These books began with the textbook Computer Networks: A Systems Approach, published in 1996. After publishing the fifth edition in 2011, they took their book "open source" by making the text freely available on Github under a Creative Common license. Now the original book is part of a series that also includes "micro-books" on SDN and 5G, with more books in preparation. In this episode, Bruce and Larry talk about their motivations and future plans, including trying to rope your host into writing a book on Open vSwitch. For more information on the series, visit systemsapproach.org or follow the series on substack as systemsapproach or Twitter as and @SystemsAppr. You can find Bruce on Twitter as @_drbruced and Larry as @_llpete. OVS Orbit is produced by Ben Pfaff. The intro music in this episode is Drive, featuring cdk and DarrylJ, copyright 2013, 2016 by Alex. The bumper music is Yeah Ant featuring Wired Ant and Javolenus, copyright 2013 by Speck. The outro music is Space Bazooka featuring Doxen Zsigmond, copyright 2013 by Kirkoid. All content is licensed under a Creative Commons Attribution 3.0 Unported (CC BY 3.0) license.

Dmitry Yusupov submitted a talk to the Open vSwitch 2020 Fall Conference that we weren't able to fit into the schedule. This podcast, recorded in December 2020, is based on the material that Dmitry presented in a video available on YouTube. The slides for Dmitry's talk are also available. The abstract for this talk is: OVSDB (management protocol RFC 7047) is a fundamental building block of modern SDN architecture based on OVN/OVS. OVSDB is the key component that is responsible for efficient scalability of large deployments, such as 1000+ node Kubernetes clusters when CNI function is OVN based. OVSDB was originally designed to store configuration for Open vSwitch daemon, however, it was later extended to be part of OVN architecture, with added RAFT clustering support and improved scale-out capabilities, such as efficient scale-out caches. This talk brings a question of scaling up OVSDB with introduction of OVSDB Query Optimizer using primary and alternate key indexing. We will be also looking at OVSDB with Query Optimizer as high-performance Key-Value API interface and compare it to ETCD. You can contact Dmitry as @dmitryy on Twitter, or via email at [email protected]. OVS Orbit is produced by Ben Pfaff. The intro music in this episode is Drive, featuring cdk and DarrylJ, copyright 2013, 2016 by Alex. The bumper music is Yeah Ant featuring Wired Ant and Javolenus, copyright 2013 by Speck. The outro music is Space Bazooka featuring Doxen Zsigmond, copyright 2013 by Kirkoid. All content is licensed under a Creative Commons Attribution 3.0 Unported (CC BY 3.0) license.

Frederick Kautz and Nikolay Nikolaev are developers on the Network Service Mesh project, which provides additional networking features for Kubernetes above what is available from Kubernetes CNI networking implementations. OVS Orbit is produced by Ben Pfaff. The intro music in this episode is Drive, featuring cdk and DarrylJ, copyright 2013, 2016 by Alex. The bumper music is Yeah Ant featuring Wired Ant and Javolenus, copyright 2013 by Speck. The outro music is Space Bazooka featuring Doxen Zsigmond, copyright 2013 by Kirkoid. All content is licensed under a Creative Commons Attribution 3.0 Unported (CC BY 3.0) license.

Nick Buraglio works in research and education and service provider networking, currently at ESnet, the US Department of Energy's science network, which links sites in the United States and western Europe. In this podcast, he talks about the role of latency monitoring in managing a network. Nick defines the latency that he's talking about: "When most people think of latency, they think of a ping round-trip time. That's one useful data point, but we're talking about very low tolerance and high accuracy latency. You have to have a cellular or GPS clock and a very strong clock source in the system to be able to track it at this level. We use that as a very important part of how we manage our network. That's really what I'm talking about when I talk about latency." Nick discusses the perfSONAR software for monitoring latency over time and for investigating problems as they occur. Some basic live monitoring charts and graphs for ESnet are online at MyESnet. You can contact Nick on Twitter as @forwardingplane or visit his blog at forwardingplane.net. Other episodes of OVS Orbit related to monitoring include Episode 46: In-band Network Telemetry and Episode 6: sFlow. OVS Orbit is produced by Ben Pfaff. The intro music in this episode is Drive, featuring cdk and DarrylJ, copyright 2013, 2016 by Alex. The bumper music is Yeah Ant featuring Wired Ant and Javolenus, copyright 2013 by Speck. The outro music is Space Bazooka featuring Doxen Zsigmond, copyright 2013 by Kirkoid. All content is licensed under a Creative Commons Attribution 3.0 Unported (CC BY 3.0) license.

There are several challenges toward making it easy for users to add support for new protocols in OVS or, equivalently, adding P4 support to OVS. This talk, given at the Dagstuhl seminar on programmable data planes in April 2019, explains the reasons that OVS doesn't already have these features, what's changing, and likely future directions. The talk includes considerable discussion with the audience. An early statement summarizes the message of the talk: ...I think that it's too hard to add support for new protocols and I think users should be able to do that fairly easily. Currently, it's really hard--it's hard for me in some cases, and if it's hard for me then I'm sure it's hard for everyone else. A little later, this quote covers Ben's philosophy on P4: Why I like P4 is because of my own personal experience with OpenFlow. At Nicira when we started out designing OpenFlow, we designed it for very much a fixed match over basically IPv4 and related fields. We knew from day 1 that that wasn't good enough, I mean, not to mention existing protocols like IPv6 that we couldn't handle, but it seemed pretty obvious that people would want to add their own. Over a couple of years, in my spare time I started tinkering with ideas for how to write a language for specifying what protocols a switch supports. It seemed like there were two possibilities that kept coming up, and yet neither one of them seemed very good. One was basically based on fixed offsets; people kept suggesting this, I think maybe even Nick McKeown suggested this at one point. I kept pointing out that fixed offsets are not going to work very well because offsets change from one packet to another. The other end of the spectrum was somebody just provides a program in some general-purpose language that extracts the headers that you want, and that also seems pretty unsatisfying because it's really hard to take a general-purpose program and look at it in terms of some of its emergent properties. You can't do much with it other than run it. I tried to come up with some languages that fit in between and then when I first saw one of the drafts of the P4 specification, I looked at it and said, "I wish I'd written this." It seems to me that it strikes a really good balance there. The remainder of the talk covers the possible directions forward for OVS and flexible protocol support, including eBPF and AF_XDP. OVS Orbit is produced by Ben Pfaff. The intro music in this episode is Drive, featuring cdk and DarrylJ, copyright 2013, 2016 by Alex. The bumper music is Yeah Ant featuring Wired Ant and Javolenus, copyright 2013 by Speck. The outro music is Space Bazooka featuring Doxen Zsigmond, copyright 2013 by Kirkoid. All content is licensed under a Creative Commons Attribution 3.0 Unported (CC BY 3.0) license.

Brad Cowie and Richard Sanger are members of the WAND Network Research Group at the University of Waikato, in Hamilton, New Zealand. They are both associated with the Faucet project, which develops an open source OpenFlow controller for enterprise networks. The first part of this talk is an introduction to Faucet. The second part talks about how Faucet became involved in SCinet at SC18, the supercomputing conference held annually in Dallas. The talk includes questions from the audience. You may wish to view Brad's slides along with the episode. For more information on Faucet, visit the Faucet website. You can reach Brad as gizmoguy on IRC or @nzgizmoguy on Twitter. Brad Cowie previously spoke with OVS Orbit in Episode 47: Routing a Production Enterprise Network with Faucet. OVS Orbit previously covered Faucet in Episode 45: Faucet and OpenFlow at Allied Telesis, Epsiode 33: Lightning Talks, and Episode 19: The Faucet SDN Controller. For another take on Faucet at SC18, you can listen to Ivan Pepelnjak interview Nick Buraglio in Episode 101 of Software Gone Wild. OVS Orbit is produced by Ben Pfaff. The intro music in this episode is Drive, featuring cdk and DarrylJ, copyright 2013, 2016 by Alex. The bumper music is Yeah Ant featuring Wired Ant and Javolenus, copyright 2013 by Speck. The outro music is Space Bazooka featuring Doxen Zsigmond, copyright 2013 by Kirkoid. All content is licensed under a Creative Commons Attribution 3.0 Unported (CC BY 3.0) license.

Levente Csikor and Gabor Retvari from the Budapest University of Technology and Economics present their talk “The Discrepancy of the Megaflow Cache in OVS” at the Open vSwitch Fall Conference in San Jose in December 2018. A few days later, they visited me to have this discussion for the podcast about their work. This episode is a discussion of their work and their results. For a synopsis of Levente and Gabor's work, please visit the OVS conference page. Slides and video of their ovscon talk are also available. OVS Orbit is produced by Ben Pfaff. The intro music in this episode is Drive, featuring cdk and DarrylJ, copyright 2013, 2016 by Alex. The bumper music is Yeah Ant featuring Wired Ant and Javolenus, copyright 2013 by Speck. The outro music is Space Bazooka featuring Doxen Zsigmond, copyright 2013 by Kirkoid. All content is licensed under a Creative Commons Attribution 3.0 Unported (CC BY 3.0) license.

Simon Horman has been an Open vSwitch contributor and committer since 2010. He currently works for Netronome, where his Open vSwitch work centers around hardware offload using the "tc" API integrated into the Linux kernel. This API allows users of Open vSwitch to transparently obtain better performance: when offload is enabled with a compatible network card, Open vSwitch works the same way, but faster. The conversation includes: Categories of NICs with hardware offload The architecture of Netronome NICs How the offload API works Handling state (such as connection tracking state) in hardware offload Limitations of hardware offload, such as memory and other resource limits Extending hardware offload to DPDK The possibility of classification-only offload Offload interaction with the OVS caching hierarchy The cost of offload Kernel politics of the offload API Applications for offload Vendor cooperation across the API Simon Horman is available on Twitter as @horms. For more information on the offload API, you might want to listen to Episode 50, with Andy Gospodarek from Broadcom. OVS Orbit is produced by Ben Pfaff. The intro music in this episode is Drive, featuring cdk and DarrylJ, copyright 2013, 2016 by Alex. The bumper music is Yeah Ant featuring Wired Ant and Javolenus, copyright 2013 by Speck. The outro music is Space Bazooka featuring Doxen Zsigmond, copyright 2013 by Kirkoid. All content is licensed under a Creative Commons Attribution 3.0 Unported (CC BY 3.0) license.