OVS Orbit Ben Pfaff

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.