The original MAE's were actually Metropolitan Area Ethernets that extended by various means to large ISP locations from NAPs. These NAPs themselves used 10, and then 100 Mb/s LAN hubs and then switches. Some of these used FDDI hubs, and then some utilized ATM and Fast Ethernet. Some are now using very high speed routing in combination with ATM, and some are also using Digital Cross Connects (DCSs aka DACSs).
The term VPN. It's a real doozy. In its original *popularized* form, a Virtual Private Network or VPN was one which consisted of software-defined routes (logical maps established in No. 4 ESSs and Digital Cross Connects) in order to allow enterprise users to dial four digit extension numbers and reach across distances and locations as though they were on the same net. Which, in effect, they were, only differently compared to seven digit dialing. Same principles, though.
Today, those same networks still exist, in fact some are called software defined networks. But these original VPNs were voice networks. Today, another sliver of users, albeit a much faster growing one, is focusing on VPN as though the concept were new, and they are applying it to data networks.
This newer variant belongs to the Internet Space to muddle the meaning further, and although it's referred to at times as a VPN, it's also called an "intranet" if certain conditions are met, and if it isn't using the public cloud, per se. Although it COULD be on the public cloud if tunneling and/or special encapsulation techniques are used.
So, which is it? Is one simply a virtual net, and the other is a virtual-virtual net?
If one is a voice virtual network using multiplexed virtual channels in a switching environment, and the other is a data virtual network using virtual channels in a routed environment, then what do I call a voice over internet protocol (VoIP) facility that actually has IP gateway hooks into an end office Class 5 switch environment?
Getting back to the historical time line, then came carrier systems, and we derived first 4, then 6, then 12, and then 24, and so on, virtual channels, all on one medium, to render a pair gain of said multiple.
Today, that multiple extends up into the tens of thousands on fiber optic systems.
Yet, if one of these virtual channels extends to a point on a switching machine, it is most often referred to as a "switched circuit!" Whatever happened to its virtuality. I suppose it's like it loses its virginity at some point when it becomes switched.
The entire scope of the usage of this term "virtuality" is overdone, or no longer meaningful from a purely semantic standpoint.
For example, at one time, when two physical metallic loops were combined onto one, through the use of whatever phantomry or multiplexing, you could have stated that one circuit was real, and the other was virtual.
Then these circuits were assimilated and taken for granted as physical switched entities, even though they were not (they were simply bit streams in a larger distributed computing environment with rather atypical, unusual, actually, methods employed at their I/O interfaces) until these streams were programmed a certain way, and then they were called virtual networked circuits.
And then came along the physical Internet which is actually made up of a bunch of virtual channels to begin with, and we decided to partition this cloud further and call the private parts virtually private internets, or VPNs, and when it suits one, we call them intranets. See what I mean? Don't get me started on extranets.
It's all bit- and byte- oriented mumbo jumbo. Noise, at this stage. There are no end-to-end physical circuits to speak of, anymore. It's all virtual.
Which, in the end, makes it all real. |
