These days, computing performance mostly hinges on the wide area network, not the "local" area network, a big change from earlier eras of computing. If you think about it, devices now communicate even with other devices in the same room, building or campus using the WAN, and not the LAN. Yes, we use Wi-Fi, but that is simply a local extensiion of the WAN network access and transport.
Local area network design parameters have changed over the past 50 years, along with changes in computing architecture. Prior to 1980, the computing devices were mainframes or mini-computers and the local networks simply needed to connect dumb terminals with the mainframe. There was limited requirement for wide area communications.
The personal computer changed all that. Relatively low-cost PCs replaced mainframes as the standard computing appliance, creating a need to connect PCs at relatively low speed (10 Mbps or less). There still was limited need for WAN communications.
Client-server dramatically increased local network communications requirements, adding servers as a centralized network element PCs needed to communicate with, on a frequent basis. That also drove requirements for LAN speed up to 100 Mbps.
In the next era of distributed or network computing, perhaps the salient new requirement was for wide area communications, as more of the computing load moved to remote data centers and required networking of branch locations.
In the present “web” era, broadband communications over wide area networks are mandatory, as processing load shifts to the far end of the WAN. There is less need for networking local devices, as most local computers interact directly with the far-end cloud data centers.
In fact, many “local” communications actually rely on connections with the far-end data centers. Cloud printing, email, messaging provide examples: the communications between local devices actually are routed across the WAN to far-end servers and back again. The “local” network uses Wi-Fi, but the logical connections are from device to far-end servers and data centers.
Local network performance requirements have changed with the architectures. Early networks did not require LAN speeds much faster than 4 Mbps to 10 Mbps. Use of distributed networks contacting far-end servers created a new need for higher-speed WAN connections. Today’s web architectures require high-speed local and wide area connections.
The Wi-Fi “local area network” access is mostly an on-ramp to the WAN. In essence, the broad global network (private IP or public internet) replaces the LAN, and each local device communicates with other local devices using the WAN. Wi-Fi, essentially, is simply the local connection to the WAN.
Application performance also has changed. Early character-based apps (either mainframe, mini-computer) did not require high-bandwidth or low-latency performance. Today’s multi-media apps do require high bandwidth as a matter of course. And some apps--especially voice or video conferencing--require low latency as well.
Coming sensor apps (internet of things) will create more-stringent demands for latency and bandwidth performance exceeding parameters for voice and video conferencing, in some use cases. Virtual reality is probably the best example of bandwidth requirements. Sensors involved with auto safety provide the best examples of latency-dependent communications.
The point is that, these days, LAN performance arguably is secondary to WAN performance.
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