Art of Network Engineering Episode 116 (Podcast)
25 March 2023 · 4 min read
I had the pleasure of joining Lexi & Andy for the AONE podcast! We talked USNUA, Ohio IX & SD-WAN. Check it out!
Why Ohio needed an exchange
Trace a route from Toledo to Toledo and it may go through Chicago and Toronto before it comes back to Cleveland. The Ohio IX exists to keep that traffic in the state. It is, at heart, a big switch in Columbus. Members bring their own ASN and address space, cross-connect, and peer either through the route servers, which are Linux boxes running BIRD on VMware, or bilaterally with whoever they want. Service providers, WISPs, regional fiber operators, content networks like Cloudflare, Fastly and Akamai, and enterprises who want to be four milliseconds from AWS us-east-2 instead of fifty. A 10G port is $1,000 a year, 100G is $2,500, and that covers support on the Arista and Juniper gear and the optics. Everyone, board included, is a volunteer.
Andy's follow-up was the useful one: would you take a volunteer with a CCNA and no production experience? Yes. The technical committee is a revolving door of people who get excited, help provision members and learn how BGP and peering actually work, then move on. There are good mentors from municipal and regional providers, and the mixers are a way into the peering community. Lexie promised to look up the Seattle Internet Exchange the moment we finished recording.
How the NUG got started
A few of us having a beer, talking about VMUG and the Linux user group, and asking why networking did not have one. The Ohio NUG started in 2017 with 15 people; by fall 2019 the Cleveland event drew 120, with folks driving up from Cincinnati. Vendor-neutral presentations on EVPN, VXLAN or multicast, a panel of engineers talking about what is frustrating them, and time to talk in between. By the time of this episode there were 13 chapters, 40 events the prior year, 60 planned, and the first dedicated employee to run them. Andy asked why "user" group rather than "operator" group: NOGs draw the content providers and ISPs solving cloud-scale problems, and this is for the enterprise engineers doing campus, data center and WAN day to day.
SD-WAN, from the beginning
Andy set up his WAN world, A-side MPLS, B-side internet sitting idle unless the primary failed, and asked me to explain what SD-WAN changes. I told the story of discovering it around 2014 as a sales engineer slinging MPLS, my rep insisting we could poke holes in it and me realizing it was better than what we sold. The acquirer of that company thought it was a gimmick; a friend who had hired me for dial-up support in 1999 said let's do it ourselves, and WAN Dynamics started in February 2016. What convinced me was yanking a circuit out of a VeloCloud edge and losing one ping.
The substance: an overlay that continuously probes every path inside its own tunnels, steers per application, and actively repairs problems with forward error correction and jitter buffering, sending two copies of a voice stream down a lossy link to get it through. It is an architecture, not a protocol; every vendor's tunnelling and controller model differ, and most replace the branch router outright. Cellular can sit idle as backup with a policy that black-holes streaming and social media when the metered link kicks in.
Where it lets you down
Andy asked whether SD-WAN lets you drop expensive MPLS, and the honest answer is sometimes. Going all-internet trades money for latency, and a Citrix shop or a call center will feel it. Executives hear "we saved a ton" from a peer with a different application stack and expect the same. Usually the cost is a wash and what you get is uptime and performance, which, as Andy said, is what we have been chasing for fifty years. Security at the edge is the other complication: pure-play SD-WAN needs a firewall integrated behind it, which is where the SASE conversation came from, and where the conversation had moved by 2023.
Lexie's last question was whether SD-WAN does anything for a home worker with one connection. It does. The same error correction and jitter buffering that make an internet circuit business-class make a bad cable modem tolerable, and that tech was already showing up inside VPN clients.
Also discussed: drums, punk rock bands, skateboarding, and the fact that Gartner considered other names before SASE. Andy would like it noted that "Slappy" was available.
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