network infrastructure

The network infrastructure is the wiring-and-fixed transceiver physical layer of the signal infrastructure (which includes also the wireless spectra used and the wireless protocols and any hosts involved). It is also sometimes called the the wired infrastructure (very broad) or network backbone (narrowing to only the major Internet Service Providers whose networks cooperate to form the Internet - a public signal infrastructure).

The network infrastructure of the largest of these providers, which meet at NAPs, cooperate to create the best known signal infrastructure, the public Internet. However, many private networks that use the same protocols but are inaccessible to any NAP will always exist. An intranet is any combination of such private networks and hosts. The term extranet is used sometimes to mean an intranet extended beyond a companies' premises, but in fact any intranet is inevitably used by teleworkers that way, so the term intranet should refer only to the signalling infrastructure, not the physical layer.

All modern network infrastructure uses packet protocols BACnet and IP with some circuit protocols, e.g. POTS, ISDN/DECT, supported as a legacy concern. Increasingly, use of VoIP and similar technologies makes the differences invisible to the user. The last mile may be analog but once the signal hits a phone switch it's turned into packets and there's no way to tell which networks are involved.


The best definition of a network infrastructure is anything managed via SNMP. The difference between different infrastructures is thus where those packets go. And only that.