
While we normally think of RFCs as standards, there is actually a lot of useful information published through the IETF process that relates to basic network engineering concepts. Since this information is specifically and intentionally vendor independent, it often goes back to the theoretical basis of a line of thinking, or explains things in a way that’s free of vendor implementation jargon. From time to time, I like to highlight these sorts of drafts, to bring them to the notice of the wider networking community.
A lot of basic research has gone into quality of service from the perspective of queuing, marking, and dropping mechanisms. The result of this research is a wide array of quality of service mechanisms, which tend to be explained either using deep math, or in terms of “look what feature we’ve implemented, and here’s how to configure it.” RFC7806, published this month, is a useful intermediary between the high math and vendor implementation styles of presentation. This RFC describes a model often used for understanding quality of service, the Generalized Processor Sharing model, and how it applies to a few packet queuing, marking, and drop strategies.
Benchmarking routing protocols might not be something you Continue reading

Today Twitter is creating and persisting 3,000 (200 GB) images per second. Even better, in 2015 Twitter was able to save $6 million due to improved media storage policies.
It was not always so. Twitter in 2012 was primarily text based. A Hogwarts without all the cool moving pictures hanging on the wall. It’s now 2016 and Twitter has moved into to a media rich future. Twitter has made the transition through the development of a new Media Platform capable of supporting photos with previews, multi-photos, gifs, vines, and inline video.
Henna Kermani, a Software Development Engineer at Twitter, tells the story of the Media Platform in an interesting talk she gave at Mobile @Scale London: 3,000 images per second. The talk focuses primarily on the image pipeline, but she says most of the details also apply to the other forms of media as well.
Some of the most interesting lessons from the talk:
Doing the simplest thing that can possibly work can really screw you. The simple method of uploading a tweet with an image as an all or nothing operation was a form of lock-in. It didn’t scale well, especially on poor networks, which made it Continue reading
Founded by Cisco UCS veterans, Diamanti built an appliance for automated container deployments with preconfigured networking and storage.

A few recent conversations that I’ve seen and had with professionals about automation have been very enlightening. It all started with a post on StackExchange about an unsuspecting user that tried to automate a cleanup process with Ansible and accidentally erased the entire server farm at a service provider. The post was later determined to be a viral marketing hoax but was quite believable to the community because of the power of automation to make bad ideas spread very quickly.
Everyone in networking has been in a place where they’ve typed in something they shouldn’t have. Whether you removed the management network you were using to access the switch or created an access list that denied packets that locked you out of something. Or perhaps you typed an errant debug command that forced you to drive an hour to reboot a switch that was no longer responding. All of these things seem to happen to people as part of the learning process.
But how many times have we typed something in to create a change and found that it broke more than we expected? Like changing a native VLAN on a trunk and bringing down Continue reading