April 25-29, 2016

Event Details

Please note: All times listed below are in Central Time Zone

The Notorious M.T.U.

The maximum transmission unit (MTU) defines the maximum size of IP packets sent over a network. Similar to physical networks, neutron contains a variety of layer-2 and layer-3 components that include MTU parameters. Improperly configuring neutron MTU parameters or options that impact MTU parameters can degrade network performance or cause packet loss in obscure places. We plan to cover the following topics:

  • Introduction to MTU: What is it and why does it matter? What is path MTU discovery?
  • Example of valid and invalid MTU configurations on a physical network.
  • Relate physical networks to virtual networks.
  • Discuss neutron MTU problems using both the Linux bridge and Open vSwitch agents on physical networks with 1500 and 9000 byte MTUs.
  • Discuss our solution to these problems.

What can I expect to learn?

Operators learn about MTU, impacts of improper MTU parameters on both physical and virtual networks, neutron MTU problems, and how to properly configure neutron MTU in various environments.

Thursday, April 28, 9:00am-9:40am (2:00pm - 2:40pm UTC)
Difficulty Level: Intermediate
Kevin Benton is a software engineer at Mirantis and the Neutron Pike PTL. He has been contributing to and supporting deployments of Neutron since 2013. His background is in security and networking. FULL PROFILE
Sean Collins is a contributor to OpenStack Neutron, previously led the Neutron IPv6 working group, and also co-organizes the OpenStack Philadelphia user group. Sean began using cloud technologies in order design scientific computation clusters, and later began developing new OpenStack features in the networking space, including support for IPv6 networking, network quality of service, and... FULL PROFILE
In late 2013, one of the networking vendors I supported became involved with OpenStack, particularly the virtual networking aspects, and asked me to develop training, demonstrations, and lab environments for their customers. While attempting to install OpenStack with Networking (neutron) for the first time, I ran into significant hurdles from issues with the installation guide. After... FULL PROFILE
Red Hat
Ihar is a software engineer at Red Hat. He spends most of his time hacking Neutron (also serving as a core reviewer for the project), nevertheless he is also interested in cross-project initiatives (Oslo, stable maintenance). Ihar is chairing the Neutron Upgrades team meetings and pushes the upgrades story for the project. Ihar is located in a European time zone,... FULL PROFILE