Network Topologies - N10-008 CompTIA Network+ : 1.2 — Transcript

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1. 0:02when you're designing building or
2. 0:03troubleshooting a network you'll be
3. 0:05using a network topology type that can
4. 0:08vary depending on the technology you're
5. 0:10using if you're looking to understand
6. 0:13the way the data is flowing or you want
7. 0:15to plan to create a new type of network
8. 0:18then it's useful to understand what
9. 0:19these topologies might be this is also
10. 0:22useful during the troubleshooting
11. 0:23process because you'll know exactly what
12. 0:25flow the traffic takes to get between
13. 0:27point a and point b one of the most
14. 0:30popular types of topologies is the star
15. 0:33topology you might also hear this
16. 0:35referred to as a hub and spoke where the
17. 0:37hub is in the middle and the spokes are
18. 0:39along the outside this is a topology
19. 0:42that you'll find on almost any network
20. 0:44regardless of the size of the network
21. 0:47and you'll also find that most devices
22. 0:49are connecting back to the central hub
23. 0:51of the star for example a switched
24. 0:54ethernet network has the ethernet switch
25. 0:57in the middle of this star and then all
26. 0:59of the devices run directly back to this
27. 1:02particular switch they're not connecting
28. 1:05to each other they're instead connecting
29. 1:07back to the central switch in this star
30. 1:09topology
31. 1:11although we don't often see a ring
32. 1:12topology used on our local area networks
33. 1:16it's still a topology type that's used
34. 1:17quite often for wide area networks so
35. 1:20although many people will remember the
36. 1:22older token ring technologies that we
37. 1:24used to run inside of our local area
38. 1:26networks we don't generally find those
39. 1:29ring networks any longer but if you're
40. 1:31connecting over a metropolitan area
41. 1:33network or a wide area network we use
42. 1:36ring networks extensively it's not
43. 1:38because a ring technology somehow lends
44. 1:41itself to work better over a wide area
45. 1:43network it's because we can create
46. 1:45additional redundancy using the ring
47. 1:48topology
48. 1:49for example very common way to send
49. 1:51traffic over a ring network is to have
50. 1:54the traffic simply go in a circle now if
51. 1:56we're on this wide area network and
52. 1:58there's construction going on and
53. 2:00someone happens to sever a fiber
54. 2:02connection that's being used for this
55. 2:04metropolitan area network then we're not
56. 2:06going to be able to send that traffic
57. 2:08through the rest of that ring but the
58. 2:10devices that are on either side of that
59. 2:13severed link recognize that traffic is
60. 2:15no longer able to traverse that
61. 2:17connection and instead will loop back
62. 2:19the connection on those individual
63. 2:22endpoints so instead of having data go
64. 2:24around a ring the data will instead go
65. 2:26to as far as it can around the ring and
66. 2:29then loop back to get to the other side
67. 2:31of the ring maintaining up time and
68. 2:34availability even in the case where part
69. 2:36of that ring may be severed
70. 2:39early types of ethernet networks were
71. 2:41not switched ethernet but were instead
72. 2:43run over coax and this coax was quite
73. 2:46simply a cable that was run down the
74. 2:48middle of the room very similar to this
75. 2:51cable this is a bus network and although
76. 2:54it was commonly used on those early
77. 2:56ethernet networks we can still find
78. 2:58modern networks that use the same bus
79. 3:00topology
80. 3:01one problem with bus networks is that it
81. 3:04is a single cable that is running either
82. 3:06through the walls or down the center of
83. 3:08the room and if we happen to have a
84. 3:11break in this cable you can see
85. 3:13immediately that it would suddenly
86. 3:15segment the network into different
87. 3:17pieces or in some cases cause no data to
88. 3:20be transferred across the network that's
89. 3:22one of the reasons we moved away from
90. 3:24bus networks for our local area networks
91. 3:27because one single disconnect could
92. 3:29cause an outage for everybody else on
93. 3:32the network
94. 3:33in our modern automobiles we have bus
95. 3:35networks that we use extensively these
96. 3:37are controller area network buses or can
97. 3:41bus connections and they're used to
98. 3:43connect all of the different sensors and
99. 3:45controllers inside of our automobiles to
100. 3:47be able to make all of our cars much
101. 3:49safer to drive on the roads
102. 3:52another popular topology especially in
103. 3:54larger networks is to create a mesh
104. 3:57between devices or a mesh between sites
105. 4:00we may have devices that are connected
106. 4:02in different locations and we might want
107. 4:04to connect them all together but instead
108. 4:06of having a single connection to a
109. 4:08particular site we may want to create
110. 4:10multiple connections to mesh these
111. 4:12together that way if we do lose any one
112. 4:15of these network links we're able to
113. 4:17work around that problem by simply using
114. 4:20one of the redundant connections
115. 4:22you'll commonly use this type of mesh
116. 4:25design if you're creating redundancy or
117. 4:26fault tolerance or perhaps you're
118. 4:28designing a load balance network and you
119. 4:30can use different parts of the network
120. 4:32to share that load
121. 4:34probably the most common place to find a
122. 4:36wired mesh network is over a wide area
123. 4:38network where you can create multiple
124. 4:41links to other sites so that you can
125. 4:43have a primary connection from one site
126. 4:45to the other and then a backup or
127. 4:47secondary connection that you can use if
128. 4:49you run into problems
129. 4:51when you start combining these different
130. 4:53topologies together you create a hybrid
131. 4:55network a hybrid network is more than
132. 4:58one of these topology types all working
133. 5:00together for example you might have
134. 5:02three remote sites all connecting
135. 5:04devices together using a switched
136. 5:06ethernet or star network and then you
137. 5:08may be connecting those together over a
138. 5:10wide area network that uses a ring
139. 5:12topology
140. 5:14if you're using a wireless network you
141. 5:16may be communicating in a number of
142. 5:18different ways if you're using an access
143. 5:20point you're probably communicating over
144. 5:22an infrastructure connection this means
145. 5:25that all of the devices on your network
146. 5:27are communicating through an access
147. 5:29point this is probably the most common
148. 5:31way to use wireless connections but it's
149. 5:33not the only way to communicate over a
150. 5:35wireless link if you just have two
151. 5:37devices and there's no access point that
152. 5:40you can use you can connect directly
153. 5:42from one device to another using ad hoc
154. 5:45networking you don't need an access
155. 5:47point or any other type of wireless
156. 5:49infrastructure you simply have one
157. 5:51device communicate directly to another
158. 5:53device over this wireless connection
159. 5:56and if you've added internet of things
160. 5:58devices which are commonly wireless
161. 6:01devices that control our lights our door
162. 6:03locks or the air conditioning systems
163. 6:06then you're probably using a mesh
164. 6:08network where all of these devices can
165. 6:10communicate to all the other devices
166. 6:12simultaneously to create an
167. 6:14interconnected mesh of communication
168. 6:17between all of these iot devices
169. 6:21one of the advantages of these mesh
170. 6:23wireless networks is that it allows many
171. 6:25devices to communicate to each other
172. 6:28even if those devices are very far apart
173. 6:30from each other this also allows the
174. 6:32mesh network to self-heal so if you turn
175. 6:35off one of those iot devices the
176. 6:37remaining devices will self-heal and
177. 6:40redesign themselves into a mesh network
178. 6:42that will allow them to continue the
179. 6:44communication
180. 6:57you