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"What can possibly go wrong?" Stories of peculiarities of modern server hardware (denog17)
After discussing building a 1 Tbps/1 Gpps load generator on commodity x86-64 hardware, one of the most common follow-up topics was the reasoning behind some of the decisions. And here I've realised that it is not commonly understood that modern systems are more complex than classic multi-socket NUMA systems, and that if you don't consider some of their peculiarities, you won't achieve the expected performance. In this talk, I want to explore what happens when you break those assumptions and how you can identify them. All examples would be based on the assumption that...
Th3 Flock of Bird s (denog17)
As Bird is evolving over the years and we now have Bird version 3 available at our fingertips, maybe we should know the capabilities of it and what performance we can expect from it.
Get some numbers in comparison with other routing stacks.
Let's take a quick look on the shiny new feathers Bird prepared for us.
Licensed to the public under http://creativecommons.org/licenses/by/4.0
about this event: https://pretalx.com/denog17/talk/XRVTP3/
Video:denog17-78857-eng-Th3_Flock_of_Bird_s_hd.mp4
Day 1 Closing (denog17)
That's a wrap on Day1, time for the social!
Licensed to the public under http://creativecommons.org/licenses/by/4.0
about this event: https://pretalx.com/denog17/talk/MVDVUL/
Video:denog17-81768-eng-Day_1_Closing_hd.mp4
QoE Matters – How Application-Level Monitoring Pinpoints Network Issues (denog17)
Network operations engineers maintain the backbone of our digital experiences, ensuring robust connectivity and managing complex routing. Yet, even with great network health, where are the current limits of today’s routing technology? What does it mean when your manager calls you and says “Our customers can’t watch Netflix!”? Can we measure how the end users experience the high variety of OTT-services, beyond classical speedtests? In this talk, we will investigate real-world scenarios where network issues, even seemingly minor ones, impacted video QoE. We'll demonstrate how solutions to these problems often go miles beyond classic...
Forwarding packets at scale - Building a Cloud Data Plane using eBPF/XDP (denog17)
At Hetzner we’ve historically used an Open vSwitch based data plane for connecting hundred thousands of cloud servers to the network. This has served us well for many years and mostly still does. We have however reached some limitations and wanted to improve scalability, resiliency and flexibility with a more specialized data plane that's tailored to our needs while being easy to operate and building a strong foundation for new features. When checking our options back in 2022, the team reached the conclusion that the best path to achieve this goal is to build and...
Entering the big Cloud Game: A journey of ups and downs towards sovereignity at scale (denog17)
This talk would be held by my two colleagues: Michael Bayr (artcodix) and Gerhard Bader (Yorizon Cloud) Yorizon Cloud is the joint venture of HOCHTIEF PPP Solutions and Thomas-Krenn.AG In these times of global political and technical threats and disruptions, we are driven by our spirit of digital sovereignty when we design a new European, de-centralized, sustainable and custom-made cloud infrastructure. In their talk, my two colleagues would give an insight into the technologies we apply, open source based and European to the core. One basic focus will be the network technology and the standardized stack that...
400G ZR+ BiDi does not exist, it can't hurt you. Or can it? (denog17)
As it's common practice, each new hacker event needs something weird and funky. For this years summer camp in the Netherlands called WHY2025, we build a 400G link over a single fibre. Since 400G BiDi does not exist (yet), we had to get creative and built something, which might be considered out of spec.
Licensed to the public under http://creativecommons.org/licenses/by/4.0
about this event: https://pretalx.com/denog17/talk/KLXJS8/
Video:denog17-78260-eng-400G_ZR_BiDi_does_not_exist_it_cant_hurt_you_Or_can_it_hd.mp4
Edge-of-Your-Seat Streaming: inside waipu’s terrabit-scale live-video CDN (denog17)
Live video stresses every layer of a CDN: traffic spikes hit terabit scale in seconds, latency budgets shrink to single-digit seconds, and a single congested peering link can stall millions of viewers. This talk walks through how we built a custom Golang edge stack that now serves 5.5 Tbps across five German PoPs. We’ll unpack the caching hierarchy, peer-aware user steering that exploits BGP and ECMP, and the trade-offs between channel affinity, cache size, and uplink utilization. We'll also touch on observability with Prometheus and client-app telemetry enriched by CMCD. Licensed to the public under...
Evolving Inter.link's Software Delivery: Lessons in Fast, Consistent, and Safe Deployments (denog17)
Automation is at the heart of Inter.link's operations. Our team manages complex software that automates the entire customer journey, from correctly accepting orders for services such as IP Transit or DDoS and translating them into precise network configurations, to setting up billing and robust monitoring. This automation is critical, allowing us to rapidly develop and deploy new features while maintaining operational excellence. Achieving this level of automation required investment in our software environment and tooling. Over time, we have significantly evolved our tooling, emphasizing easy and consistent environment setups, and we have implemented robust CI/CD...
Channelmania! – future proof your DWDM network topology while keeping it flexible for 1.6T (denog17)
Past approaches for maximizing the data capacity per fiber pair went for running more and more DWDM channels with grid spacings as small as possible. This meant that grid spacings shrank from 200GHz to 100Ghz and then 50GHz with some applications even going for 25Ghz. In recent years the bandwidth per channel kept increasing, as complex modulation schemes came into favor over ON-OFF-Keying which has been a staple in fiber optic communication for decades. Those increased per channel bandwidths of 400Gbps, 800Gbps and now pushing into the 1.6Tbps realm demand for lager grids to...