jm + ospf   2

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
'Monitoring and detecting causes of failures of network paths', US patent 8,661,295 (B1)
The first software patent in my name -- couldn't avoid it forever :(
Systems and methods are provided for monitoring and detecting causes of failures of network paths. The system collects performance information from a plurality of nodes and links in a network, aggregates the collected performance information across paths in the network, processes the aggregated performance information for detecting failures on the paths, analyzes each of the detected failures to determine at least one root cause, and initiates a remedial workflow for the at least one root cause determined. In some aspects, processing the aggregated information may include performing a statistical regression analysis or otherwise solving a set of equations for the performance indications on each of a plurality of paths. In another aspect, the system may also include an interface which makes available for display one or more of the network topology, the collected and aggregated performance information, and indications of the detected failures in the topology.


The patent describes an early version of Pimms, the network failure detection and remediation system we built for Amazon.
amazon  pimms  swpats  patents  networking  ospf  autoremediation  outage-detection 
may 2014 by jm

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