Now, as mentioned, VPNs or virtual private networks have replaced a lot of deployments of leased lines,
but you'll still find them.
They've been around for a very long time, and depending where you are in the world, this may be the
only way to get a high speed connection to a business site.
Now, because these have been around a long time and have been used in various parts of the world they
often referred to with different terms or different names.
So the first term is a leased line, which once again implies that you are leasing the line from a provider.
You don't own the connection.
You are paying a monthly fee, in other words, a monthly leasing fee to lease the line from the service
provider, which would typically be a telephone company or telco such as AT&T or British Telecom.
So some terms that you may come across include leased circuit or leased line.
These terms are often used interchangeably.
A circuit refers to the actual electrical circuit between the two endpoints.
In the old days, we used to have circuit switched networks.
Where you'd make a telephone call between two sites and use an analog modem to send traffic between
those two sites.
So it was a circuit that was established for the duration of your telephone call.
A leashed line, however, is a dedicated circuit between two sites, so you don't have to make a call
to send data across it.
It's a permanent point to point connection between the two sites.
You may also come across the term serial link or serial line.
Once again, these are used interchangeably and mean the same thing.
The term serial in this case refers to the fact that the bits sent across the wire flow serially and
that routers use serial interfaces to make the connection a point to point link or point a point at
least line refers to the fact that you are making the connection between two points rather than between
multiple sites at the same time.