There's a lot of open source that glues the internet together (e.g. most of the DNS infrastructure, essentially the largest distributed database in the world, i

There's a lot of open source that glues the internet together (e.g. most of the DNS infrastructure, essentially the largest distributed database in the world, is run on open source software). When it comes to the actual shuffeling of packets, it's mostly done by proprietary hardware though - but there's no lack of open source there either, there's plenty of routers and routing protocols available (and cools stuff like openvswitch). One step up from there, there's quite a lot of work done on distributed databases, load balancers, distributed virtualization, service provisioning (e.g. platforms such as opendaylight, cassandra/hadoop, puppet)