In this lesson,
we're going to cover cable connections,
often referred to as DOCSIS connections.
Now, DOCSIS is a prevalent technology these days
that brings high-speed internet
into the homes and offices through the same lines
that deliver your favorite TV shows.
When you're watching a thrilling movie on cable TV
and simultaneously browsing the internet,
little did you realize that these two streams of data
are actually going over the same exact cable,
thanks to the wonders of a system known as HFC,
or the hybrid fiber-coaxial
and a little known standard called DOCSIS,
which stands for Data Over Cable Service
Interface Specification.
Let's start by taking a look at the backbone
of this technology,
which is the hybrid fiber-coaxial network,
or the HFC network.
Think about the HFC network as a high-capacity highway
that smoothly carries vast amounts of data
using a blend of fiber optic and coaxial cables.
The fiber optic cables are known
for their high-speed data transmission capabilities,
and they can cover longer distances,
typically from the service provider's facility
to a distribution point near your home.
From there, the coaxial cables,
the same ones used for your cable TV,
will take over and deliver data
directly to your home or office.
This blend ensures a robust
and efficient delivery of high-volume data,
and this makes it an ideal solution
for data-hungry networks at your home or office.
Now, let's take a look at DOCSIS.
DOCSIS is a suite of specifications
that standardizes how data is transmitted
over a hybrid fiber-coaxial network.
It ensures that regardless of your location
or the service provider, your cable modem,
which is that device that connects your home network
over to the internet,
speaks the same language
as the rest of the cable internet world.
This standardization is crucial for maintaining consistent,
reliable, and high-speed internet access.
Now, DOCSIS specify certain frequency ranges
for upstream and downstream transmissions,
which essentially means it designates specific lanes
for sending data to and from the internet.
Typically, the upstream,
or the data you're sending out from your house,
like your emails and uploaded files,
will use a range between five and 42 megahertz,
while your downstream,
or the data you're receiving,
like streaming video and website content,
operates between 50 and 860 megahertz.
This separation helps in managing traffic efficiently
and ensures that your request for data
and the incoming data
don't collide in a digital traffic jam.
Now, one of the things you need to note here
is that when you're dealing with a cable modem,
they're almost always going to be asynchronous
in terms of their upload and download speeds.
What that means is that you're going to expect
to get very high download speeds,
but rather slow upload speeds.
For example, at my current home,
I only have the option of using a cable modem,
and when I use that cable modem,
it's relying on this DOCSIS standard.
I've paid for one gigabit per second of service,
which is what I get when I do downloads.
But when I'm uploading things like this video
to our servers,
I'm only able to get around 30 to 40 megabits per second.
And this goes back to those ranges we just covered.
When I talked about downloads,
we talked about going from 50 to 860 megahertz,
which is 810 megahertz worth of bandwidth.
But when we talked about the uploads,
we only talked about between five and 42 megahertz,
which means we only have 37 megahertz of bandwidth.
So you can see there's a drastic difference
between the amount you can download
and what you can upload when using a cable modem.
Now, one of the most compelling aspects
of using cable connections like DOCSIS
is their use of the existing cable TV infrastructure.
This infrastructure was already going
through most of our neighborhoods,
making the rollout of cable internet really cost effective
and very quick to do,
as opposed to having to rewire entire neighborhoods
for fiber connectivity.
Now, this means for users that transitioning to
or adopting cable internet was a really convenient option
because it offered much higher speeds
than the thing at the time,
which was known as DSL,
or digital subscriber lines,
that were popular back in the late 1990s and early 2000s
when cable modes were starting to gain prevalence.
As the technology evolved, though, so did DOCSIS,
with several versions improving upon the speed, efficiency,
and security of the system.
From DOCSIS 1.0 to the latest versions,
each iteration has brought enhancements
that allowed for faster internet speed
up to one or even five gigabits per second on the downloads,
better performance,
and more robust security features
to ensure that users' data
was zooming across the network safely and swiftly.
So remember, if you hear the terms HFC or DOCSIS,
they're more than just acronyms.
They are pillars that support much
of our high-speed internet access today
when you're using cable modems and cable connections.
Whether you're streaming high-definition movies,
attending video conferences,
or engaging in online gaming,
if you're using a cable connection, you're relying on DOCSIS
to ensure your digital experience is speedy and seamless.