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The main WAN (wide area network) of this world is the one named "The Internet" although there might be others I don't know of.
Contrastingly, there is no "main" LAN (local area network) because any human could start a LAN on their own.
I wonder if the difference between WANs and LANs is qualitative AND quantitative or ONLY quantitative.
Is there a rigorous difference between a WAN and a LAN?
Historically, very different technologies were used for WAN and LAN in the past decades. Today, it's all becoming Ethernet that started out as a LAN-only technology, but has significantly increased its link reach, from 500m to 100 km. Accordingly, it covers LAN, MAN and WAN today (plus shorter reaches).
So, all that differs now is the physical-layer variant - LAN uses twisted pair and multi-mode fiber, WAN uses single-mode fiber (low-end WAN also uses voice-grade twisted pair). But of course you can use any suitable PHY variant for either LAN or WAN as required. Single-mode fiber within a data center is rather common.
Logically, different addressing schemes are used for IPv4: private LAN vs. public WAN, requiring translation in between (NAT/NAPT). For IPv6, different schemes also exist (link-local, site-local, public), but they're used in an overlapping fashion, without need for translation.
Security-wise, LAN usually means trusted and WAN means untrusted. A firewall is required in between, filtering out unwanted traffic.
All in all, there are certainly rigorous differences in specific situations, but those depend.
Typically, you would not call The Internet a Wide Area Network, because The Internet is not a network, it is a Network-of-Networks (hence the name Internet).
In general, all of those terms are not strictly defined, it is more a "I know it when I see it" kind of thing. I remember back in my "Next Generation Internet" classes (which were actually "ATM is the coolest thing ever and will take over the world" classes), we were using powers of ten to distinguish them:
But this classification is as arbitrary as any other. Also, I can't remember if we had something between PAN and LAN, or BAN and PAN. I certainly feel there should be a "xAN" acronym for the NFC/RFID space.
Yes there is rigorous difference between LAN & WAN. It's all about connectivity . Connection computers and server within same super net is referred as LAN where as connecting others networks with for purpose of shareing resources is called as WAN (wide area network ) .
Local Area Network (LAN):
LAN is a group of network devices which allow the communication between connected devices. The private ownership has the control over the local area network rather than public. LAN has short propagation delay than MAN as well as WAN. It covers the smallest area such as: School , organization's and so on within a building..
Wide Area Network (WAN):
WAN covers the large area than LAN as well as MAN such as: Country/Continent etc. WAN is expensive and should or might not be owned by one organization. PSTN or Satellite medium are used for wide area network.
I wonder if the difference between WANs and LANs
Here is what I learned.
LAN: is used for private homes and companies.
WAN: is used to connect LAN's.
