Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated:
1
00:00:00,420 --> 00:00:05,000
We'll be discussing typologies and a lot more details throughout the course.
2
00:00:05,010 --> 00:00:10,120
But I want to introduce you to the concept of physical versus logical typologies.
3
00:00:10,200 --> 00:00:15,180
We've mentioned that networks have both a physical and logical typology.
4
00:00:15,180 --> 00:00:22,040
The physical topology of a network refers to the physical layout of the devices and cabling you mismatch
5
00:00:22,080 --> 00:00:28,470
the appropriate physical typology to the top of cabling that you will install which may be twisted pay
6
00:00:28,950 --> 00:00:32,920
correctible cabling or fiber cabling as an example.
7
00:00:33,000 --> 00:00:39,150
Understanding the type of cabling used is important in each type of physical typology.
8
00:00:39,150 --> 00:00:46,380
The logical topology however defines the logical path that data will travel from one point to another.
9
00:00:46,380 --> 00:00:49,160
In the past we had devices called hubs.
10
00:00:49,230 --> 00:00:56,610
These devices were connected in what was called a star physical topology but logically the topology
11
00:00:56,610 --> 00:00:57,830
was a bus.
12
00:00:57,840 --> 00:01:01,350
So let's look at some of these typology types.
13
00:01:01,470 --> 00:01:08,250
The first type is bus in early bus typologies computers and other network devices were cobbled together
14
00:01:08,250 --> 00:01:16,680
in a line using coaxial cable modern bus typologies establish the bus in a hardware device and connect
15
00:01:16,780 --> 00:01:21,130
the host devices to the bus using twisted pay wiring.
16
00:01:21,240 --> 00:01:27,020
A ring was used by technology such as token ring and FDDI.
17
00:01:27,210 --> 00:01:34,350
In the past in a ring topology the computers and network devices were cobbled together with the last
18
00:01:34,350 --> 00:01:39,870
device connected to the first device which formed a circle or ring.
19
00:01:39,900 --> 00:01:46,600
Each device is connected to exactly two neighbors and doesn't have a connection to a third device.
20
00:01:46,770 --> 00:01:53,730
The physical connection used here was either co-axial or fiber cabling in a star topology which is one
21
00:01:53,730 --> 00:02:02,100
of the most common physical implementations a central device has other devices connected to it.
22
00:02:02,130 --> 00:02:10,110
So a switch would have PCs connected to it in a star topology physical cabling these days is typically
23
00:02:10,110 --> 00:02:14,350
done using twisted pair wiring in a mesh.
24
00:02:14,580 --> 00:02:18,740
Every device is connected to multiple other devices.
25
00:02:18,790 --> 00:02:25,800
This increases reliability and provides for self-healing because of the redundant lengths the physical
26
00:02:25,800 --> 00:02:30,210
connection could be made using fiber or twisted pay wiring.
27
00:02:30,360 --> 00:02:37,140
The logical topology however is different as it shows where data travels to get from one end point to
28
00:02:37,140 --> 00:02:42,010
another which may be very different to a physical implementation.
29
00:02:42,300 --> 00:02:49,020
Later in this course I'm going to show you how a hub is physically a start apology but logically acts
30
00:02:49,050 --> 00:02:50,860
as a bus topology.
31
00:02:51,150 --> 00:02:57,840
It's important in networking to not just look at the physical topology of a network but to also view
32
00:02:58,170 --> 00:03:05,880
the logical topology because that may be very different to the physical design and may affect network
33
00:03:05,910 --> 00:03:09,130
throughput reliability and scalability.
34
00:03:09,850 --> 00:03:16,540
One of the skills that you'll need to gain as a network engineer is how to interpret a network diagram
35
00:03:17,230 --> 00:03:25,440
a network diagram captures network related information and the amount of information varies from one
36
00:03:25,440 --> 00:03:27,030
organization to another.
37
00:03:27,880 --> 00:03:35,540
A network diagram is essentially a map of the network and illustrates the logical representation of
38
00:03:35,540 --> 00:03:42,790
the devices in the network and helps clarify how the devices are interconnected.
39
00:03:43,160 --> 00:03:50,620
In addition a well-designed network diagram provides information such as the interface IDs of devices
40
00:03:51,580 --> 00:03:58,660
device identifiers as well as network addressing common network icons that you may come across include
41
00:03:59,010 --> 00:04:08,950
work group line switches routers wireless access points servers and use a desktop PCs and use the laptops
42
00:04:09,700 --> 00:04:18,150
Ethernet links serial links wireless links and networks which could be used to represent the internet
43
00:04:18,860 --> 00:04:21,240
and access network or a lab network.
4873
Can't find what you're looking for?
Get subtitles in any language from opensubtitles.com, and translate them here.