Time
8 hours 53 minutes
Difficulty
Beginner
CEU/CPE
11

Video Transcription

00:00
Welcome back to Devein four or the county a IittIe fundamentals class,
00:06
and we're now in Module 4.2,
00:10
where Camped here asks us to compare and contrast cellular, wireless and wired connections
00:19
specifically to compare the following for those types of connections,
00:24
how mobile they are, how available and reliable they are,
00:28
what bandwidth they offer, which offered the best band win
00:32
on how secure each type is.
00:36
So first, let's talk about mobility. This refers to the ability to be able to move around while still remaining connected to the network.
00:44
Obviously, the lowest mobility is offered by wired networks. If I want to move a wired device around, I have to unplug the network connection, then possibly the power connection, then moved the device, then plug everything back in
00:58
so it doesn't really facilitate mobility.
01:00
On the other hand, when you think about WiFi,
01:03
WiFi device offers much greater mobility. If you're connected to a WiFi network, you can move around and remain connected.
01:12
The only limit is if you move too far away from the home router or wireless access point, and that signal becomes too weak, so that could be fairly limited range. You can move maybe within about 30 meters or so before the signal starts to drop, but still much more mobile than a wired network.
01:32
But the greatest mobility is with cellular connections. So if you think about your smartphone connected to your cell phone provider
01:38
and maybe you're accessing the Internet through it,
01:42
you can move around of a large geographical areas and remain connected.
01:47
As long as you're somewhere within reach of one of their cell towers,
01:51
Um, then you're going to remain connected.
01:53
So possibly you could move around an entire city or an entire region and remain connected all the time.
02:00
So
02:01
in terms of mobility, it is cellular connections that offer us the greatest mobility,
02:09
availability, and reliability talks about something very similar. How reliable is the network
02:16
on DDE?
02:17
Is it available all the time, or do that sometimes become unavailable?
02:23
Well, obviously, wired connections are the most reliable of all
02:27
and typically available 24 hours a day, seven days a week.
02:31
WiFi is also fairly reliable, but not as reliable as Wyatt connections.
02:38
How reliable it is on. You know how good a connection you get
02:43
depends on all number of factors such as how far away you are from your home router or while its access point.
02:50
Or
02:51
what about
02:53
interference from the environment?
02:55
So
02:57
anything that generates electromagnetic fields like electric motors, C R T monitors, fluorescent lighting and microwave ovens can interfere with that signal.
03:07
And signals also can get blocked by metallic structures. And even things like mirrors can bounce the signal of weight.
03:15
So
03:16
and therefore it's
03:19
availability may not be as great as his wired networks. If I'm connected to a WiFi network and I move around, if I move too far away from the Access Point or home router that could break the connections, though, it's no longer available to me
03:32
if somebody starts up a microwave oven. That could break my connection. Because microwave ovens generates strong fields on exactly the same wave band that many WiFi networks use 2.4 gigahertz.
03:51
But cellular data is probably the least reliable, and you probably already know that from using your cell phone.
03:58
Sometimes the signal's a week. Sometimes you're in the middle of a call, and the signal drops
04:04
in some places you can't even get a signal at all. And so on.
04:10
So wired networks generally are the most reliable and highly available.
04:14
Cellular connections are the least reliable and possibly less available.
04:21
And then there's bandwidth. So to compare the different types, wired networks typically operate today at one gigabit per second. So that's some fairly good bandwidth for most operations that we might want to do in the network
04:36
wireless networks very a lot, depending on which standard you're using.
04:41
So earlier standards like
04:43
11 B, for example, operated a very slow 11 megabits per second.
04:48
Today, the current standards you'll find that many home raptors are eight or $2.11 n, and some are eight or $2.11 a seat,
04:58
so that potentially gives you speeds of up to 150 megabits. But second with 11 n
05:02
and
05:03
up to possibly one gigabit per second with 11 a C nine Reality With WiFi,
05:10
the bandwidth that is quoted is usually the maximum.
05:13
So in reality, if you have an eight or $2.11 a C home router
05:17
and a NATO to door 11 a C device
05:20
and you establish a connection in good conditions, it might actually be around 8 to 900 megabits per second.
05:29
the standard 802 11 a. C
05:31
theoretically defined speeds of up to seven gigabits per second, where that requires highly specialized
05:39
routers or access points with multiple antennas. And currently the devices on offer typically offer a maximum speed of around one gigabit per second.
05:51
And then there is Bluetooth.
05:55
Now, strictly speaking, Bluetooth is not
05:58
really
06:00
general network connectivity solution. You'll remember from an earlier module that Bluetooth is a
06:05
peer to peer connection technology. It connects one device to one other device.
06:12
So, for example, you can connect your wireless keyboard or wireless mouths to your PC using Bluetooth. Or you can connect your smartphone to your desktop computer using Bluetooth.
06:24
It operates at a fairly low speed of about 25 megabits per second.
06:28
But remember, this is often used to connect slower devices. Anyway, Your keyboard in your mouths are pretty slow devices,
06:34
you know, in computing terms, so that connection is usually plenty fast enough for that kind of thing.
06:46
Now I've been using the word speed when I talk about bandwidth, but it is actually technically not a measure of speed.
06:56
Speed is expressed as they'd elect Insee of the connection
07:00
and it's measured simply like this. If I send a packet out across the network to a destination device,
07:08
and then I got a response from it.
07:10
How long does that take?
07:12
And Leighton see can be measured in milliseconds that is 1/1000 of a second.
07:17
So
07:21
in order to measure Leighton, see, you can use a very simple utility called Ping. Not normally the way Ping is used is to test connectivity between any two devices,
07:31
but as a byproduct of its testing, it shows you the Leighton see of the connection.
07:36
So let's have a look at this.
07:39
What I'm gonna do is Ping Microsoft's Web server
07:43
from my location here in America. So I'm picking one computer
07:49
to another computer within the same country,
07:53
and if you look at the late and see, it varies between 11 milliseconds and 59 minutes seconds.
07:59
Now I'm going to pain
08:01
a server located in the United Kingdom,
08:05
and they're the latents. A year somewhat higher on the highest is 133 milliseconds.
08:11
Now, obviously,
08:13
that is slower than pinging a device here in America,
08:20
But even so when you think about what was achieved in that 133 milliseconds.
08:26
A network packet went out from my computer, traveled across the Internet across the Atlantic Ocean
08:33
to go hit a server in the UK, And then the server responded, and the response came back,
08:37
and all of that happened in a fraction of a second.
08:41
133 milliseconds is about 1/10 of a second,
08:45
so it's still pretty fast, even over vast distances.
08:50
So there you can see anon. Leighton see, is really a measure of the speed of the connection.
08:58
So then why is it that we talk about bandwidth well, one reason days
09:03
when Internet service providers are trying to sell you a connection. They talk about bandwidth and no lake and see.
09:09
But let me ask you this question. If you have a two lane highway at an eight lane highway and they both have the same speed limit or 55 miles an hour, which one's faster?
09:20
Well, the answer is neither. It's faster because they both have the same speed limit.
09:24
Whichever highway you travel on, if you're going to stick within the law, you can't go faster than 55 miles an hour,
09:31
so
09:33
What about if you have lots of traffic, though,
09:37
on an eight lane highway, you can have cars traveling in parallel along the airplanes, and so you're going to get much better throughput or trying to get lots of cars through an eight lane highway that you would a two lane highway. So here's what we can say. The eight lane highway is not faster, but it has a larger capacity
09:56
than the two lane highway.
10:00
Now let's apply that analogy to network speeds.
10:03
Bandwidth is really, technically a measurement of the capacity of the connection.
10:09
Leighton see is a measure of the actual speed.
10:13
Now, one reason why we all
10:15
talk about bandwidth as the speed
10:18
is partly because we have been conditioned into it by the I. S. P's, the Internet service providers. Because when they talk about bandwidth, when they're selling you an Internet connection,
10:28
they don't talk about the Leighton. See, they're not telling you how *** is to get a packet out to another machine and back again through that connection.
10:35
What they're really selling you is increased capacity.
10:39
But often the implication is,
10:43
if you get a 50 megabits per second connection is gonna be twice as fast as a 25 megabits per second connection, and sometimes it can appear that that way.
10:52
But here's what they're actually selling you. They're selling, you increase capacity.
10:54
So let's say you have a 25 megabits per second connection, and you have five users all simultaneously streaming movies across that connection,
11:05
so it might be sufficient to support all of that. But if you had maybe 10 20 users,
11:09
you might start to see that connection become a bottleneck because it doesn't have the capacity to handle 10 or 20 simultaneous streams.
11:18
If you have a 50 megabits per second connection that maybe 10 or 20 users can easily simultaneously be streaming movies through that connection.
11:28
And what you're therefore benefiting from is the increased capacity of the connection, rather than the increased speed of that connection.
11:35
Because the speed is probably the same,
11:41
um,
11:43
so comparing connections. Generally
11:46
wired connections have the lowest leighton see,
11:48
meaning that they are actually faster
11:50
and have the highest van Wyk, meaning that have the most capacity.
11:56
WiFi has a somewhat higher leighton, see and remember, high latency is bad. No good
12:01
on DDE
12:03
usually has a lower bandwidth, then
12:05
the wire connection
12:07
and then generally cellular data often has the highest Leighton see of all
12:13
on the lower sponge wit.
12:16
So
12:18
concurrent connections.
12:20
Wired networks are designed to support large numbers of simultaneous device connections, so they have very high capacity.
12:28
So
12:31
in a Soho network small office Home Office network,
12:35
you're unlikely to run into any limits or any problems
12:39
because typically in those types of networks, you have maybe 2030 40 devices
12:43
in a corporate network where they might have hundreds or even thousands of devices.
12:48
Well, in that case, they may have to take special steps to make sure that everybody's getting optimal connections in terms of relate insee on bandwidth usage.
12:58
Wife I, on the other hand, often does have a practical limit, particularly for home routers rather than enterprise. While wireless access points for home routers there may well be limits us to the number of wireless devices that can actually connect simultaneously to the home router
13:15
on dhe. Also, bear in mind this
13:18
the band width over WiFi network is shared between all the devices. So if your wife eyes operating at 100 megabits per second
13:26
and there are 10 devices connected on average, each one is getting about 10 megabits per second as the actual useful bandwidth.
13:39
In terms of security, wired networks win hands down because in order to tap into a wired network, if a malicious user wants to gain access to it,
13:48
they generally have to gain physical access to the building and physical access to the wires. Themselves were at least some of the networking devices, like switches or writers, but all of that requires getting physical access.
14:01
Wireless networks are inherently less secure because
14:05
they're the packets are not safely enclosed inside wires.
14:09
The packets are getting broadcast as radio waves,
14:13
and they will reach out further than you might realize, so they'll reach out of the office. Maybe they'll reach into neighboring buildings and onto the street.
14:22
And therefore anybody with a WiFi device
14:26
and the desire to break into your network will find it much easier to try and break into a WiFi network because they don't need to have physical access to any of your devices or your premises.
14:41
And because WiFi is inherently less secure. This is why security of WiFi it's so important.
14:48
So you know, as we said. In the last module,
14:50
all your WiFi devices should be configured to use W p A. To as their security mechanism rather than the earlier WEP or W P. A.
15:03
So to summarize,
15:05
a model 4.2, we were asked to compare and contrast cellular, wireless and Wyatt data connections in relation to their mobility,
15:15
and we saw cellular connections of the most mobile
15:18
in terms of availability and reliability. Generally, Wired networks went out, as they are the most reliable and highly available
15:28
in terms of bandwidth. Wired networks went out because they're for the greatest band width and the lowest Leighton see,
15:33
And in terms of security, wired networks went out because they are the most secure type of backward.

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