jm + anycast   5

RIPE Atlas Probes
Interesting! We discussed similar ideas in $prevjob, good to see one hitting production globally.
RIPE Atlas probes form the backbone of the RIPE Atlas infrastructure. Volunteers all over the world host these small hardware devices that actively measure Internet connectivity through ping, traceroute, DNS, SSL/TLS, NTP and HTTP measurements. This data is collected and aggregated by the RIPE NCC, which makes the data publicly available. Network operators, engineers, researchers and even home users have used this data for a wide range of purposes, from investigating network outages to DNS anycasting to testing IPv6 connectivity.

Anyone can apply to host a RIPE Atlas probe. If your application is successful (based on your location), we will ship you a probe free of charge. Hosts simply need to plug their probe into their home (or other) network.

Probes are USB-powered and are connected to an Ethernet port on the host’s router or switch. They then automatically and continuously perform active measurements about the Internet’s connectivity, and this data is sent to the RIPE NCC, where it is aggregated and made publicly available. We also use this data to create several Internet maps and data visualisations. [....]

The hardware of the first and second generation probes is a Lantronix XPort Pro module with custom powering and housing built around it. The third generation probe is a modified TP-Link wireless router (model TL-MR 3020) with a small USB thumb drive in it, but this probe does not support WiFi.


(via irldexter)
via:irldexter  ripe  ncc  probing  active-monitoring  networking  ping  traceroute  dns  testing  http  ipv6  anycast  hardware  devices  isps 
12 weeks ago by jm
Seesaw: scalable and robust load balancing from Google
After evaluating a number of platforms, including existing open source projects, we were unable to find one that met all of our needs and decided to set about developing a robust and scalable load balancing platform. The requirements were not exactly complex - we needed the ability to handle traffic for unicast and anycast VIPs, perform load balancing with NAT and DSR (also known as DR), and perform adequate health checks against the backends. Above all we wanted a platform that allowed for ease of management, including automated deployment of configuration changes.

One of the two existing platforms was built upon Linux LVS, which provided the necessary load balancing at the network level. This was known to work successfully and we opted to retain this for the new platform. Several design decisions were made early on in the project — the first of these was to use the Go programming language, since it provided an incredibly powerful way to implement concurrency (goroutines and channels), along with easy interprocess communication (net/rpc). The second was to implement a modular multi-process architecture. The third was to simply abort and terminate a process if we ended up in an unknown state, which would ideally allow for failover and/or self-recovery.
seesaw  load-balancers  google  load-balancing  vips  anycast  nat  lbs  go  ops  networking 
january 2016 by jm
Shutterbits replacing hardware load balancers with local BGP daemons and anycast
Interesting approach. Potentially risky, though -- heavy use of anycast on a large-scale datacenter network could increase the scale of the OSPF graph, which scales exponentially. This can have major side effects on OSPF reconvergence time, which creates an interesting class of network outage in the event of OSPF flapping.

Having said that, an active/passive failover LB pair will already announce a single anycast virtual IP anyway, so, assuming there are a similar number of anycast IPs in the end, it may not have any negative side effects.

There's also the inherent limitation noted in the second-to-last paragraph; 'It comes down to what your hardware router can handle for ECMP. I know a Juniper MX240 can handle 16 next-hops, and have heard rumors that a software update will bump this to 64, but again this is something to keep in mind'. Taking a leaf from the LB design, and using BGP to load-balance across a smaller set of haproxy instances, would seem like a good approach to scale up.
scalability  networking  performance  load-balancing  bgp  exabgp  ospf  anycast  routing  datacenters  scaling  vips  juniper  haproxy  shutterstock 
may 2014 by jm
DuckDuckGo Architecture - 1 Million Deep Searches a Day and Growing
thumbs-up for DNSMadeEasy's Global Traffic Director anycast-based geographically-segmented DNS service, in particular
dns  architecture  scalability  search  duckduckgo  geoip  anycast 
january 2013 by jm

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