№42

... it's better to have good questions

UDP tuning and performance testing

October 17, 2024 1 min read Linux Networking Ronny Trommer

Problem statement

  • Ingesting UDP traffic is complicated to measure
  • Packet drops, connectionless and unreliable
  • Measuring on ingest on the network interface card
  • How can you make sure you measure reasonably?
  • You want a method to create some confidence how many UDP packets your system drops

Create a lab environment to reproduce the problem

  • Make the problem visible using with overloading a small device Raspberry Pi 3
  • Use sysctl default settings
  • Use something like hping3 or iperf to create a overload situation

You can’t improve what you don’t measure

  • Show tools like dropwatch or ss -lump or SNMP udp metrics to visualize packet drops
  • Compare packets received with tcpdump vs. iperf
  • Theory should show who be tcpdump should have more but not all then the sender

Increase buffers size?

  • What happens if you increase the buffer size?

Use PF_RING

  • How does the behavior change when you use PF_RING with TCPDUMP

Conclusion

IPv6 prefix delegation with FRITZ!OS 7.50 and Ubiquiti ER-4

February 14, 2023 2 min read Networking IPv6 How-To Ronny Trommer

I started working remotely in 2010 for OpenNMS as an open-source network monitoring advocate. I have a little home lab with some real hardware that allows me to play on various things without giving me a big surprise bill from a cloud provider at the end of the month. I have a FRITZ!Box 7530 connected to my ISP 1&1. I get native IPv6 and IPv4 connectivity over an IPv4-in-IPv6-Tunnel. As my main router, I have a Ubiquiti ER-4. It gives me enhanced firewall capabilities and flexibility, especially with routing protocols like OSPF and BGP. I have two networks, one for my work-related stuff and another with all the fun crap you have for fun at home.

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