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when you're designing building or

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troubleshooting a network you'll be

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using a network topology type that can

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vary depending on the technology you're

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using if you're looking to understand

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the way the data is flowing or you want

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to plan to create a new type of network

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then it's useful to understand what

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these topologies might be this is also

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useful during the troubleshooting

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process because you'll know exactly what

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flow the traffic takes to get between

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point a and point b one of the most

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popular types of topologies is the star

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topology you might also hear this

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referred to as a hub and spoke where the

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hub is in the middle and the spokes are

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along the outside this is a topology

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that you'll find on almost any network

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regardless of the size of the network

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and you'll also find that most devices

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are connecting back to the central hub

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of the star for example a switched

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ethernet network has the ethernet switch

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in the middle of this star and then all

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of the devices run directly back to this

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particular switch they're not connecting

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to each other they're instead connecting

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back to the central switch in this star

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topology

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although we don't often see a ring

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topology used on our local area networks

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it's still a topology type that's used

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quite often for wide area networks so

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although many people will remember the

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older token ring technologies that we

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used to run inside of our local area

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networks we don't generally find those

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ring networks any longer but if you're

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connecting over a metropolitan area

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network or a wide area network we use

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ring networks extensively it's not

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because a ring technology somehow lends

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itself to work better over a wide area

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network it's because we can create

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additional redundancy using the ring

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topology

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for example very common way to send

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traffic over a ring network is to have

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the traffic simply go in a circle now if

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we're on this wide area network and

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there's construction going on and

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someone happens to sever a fiber

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connection that's being used for this

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metropolitan area network then we're not

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going to be able to send that traffic

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through the rest of that ring but the

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devices that are on either side of that

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severed link recognize that traffic is

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no longer able to traverse that

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connection and instead will loop back

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the connection on those individual

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endpoints so instead of having data go

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around a ring the data will instead go

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to as far as it can around the ring and

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then loop back to get to the other side

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of the ring maintaining up time and

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availability even in the case where part

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of that ring may be severed

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early types of ethernet networks were

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not switched ethernet but were instead

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run over coax and this coax was quite

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simply a cable that was run down the

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middle of the room very similar to this

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cable this is a bus network and although

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it was commonly used on those early

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ethernet networks we can still find

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modern networks that use the same bus

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topology

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one problem with bus networks is that it

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is a single cable that is running either

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through the walls or down the center of

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the room and if we happen to have a

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break in this cable you can see

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immediately that it would suddenly

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segment the network into different

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pieces or in some cases cause no data to

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be transferred across the network that's

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one of the reasons we moved away from

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bus networks for our local area networks

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because one single disconnect could

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cause an outage for everybody else on

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the network

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in our modern automobiles we have bus

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networks that we use extensively these

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are controller area network buses or can

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bus connections and they're used to

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connect all of the different sensors and

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controllers inside of our automobiles to

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be able to make all of our cars much

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safer to drive on the roads

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another popular topology especially in

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larger networks is to create a mesh

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between devices or a mesh between sites

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we may have devices that are connected

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in different locations and we might want

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to connect them all together but instead

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of having a single connection to a

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particular site we may want to create

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multiple connections to mesh these

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together that way if we do lose any one

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of these network links we're able to

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work around that problem by simply using

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one of the redundant connections

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you'll commonly use this type of mesh

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design if you're creating redundancy or

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fault tolerance or perhaps you're

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designing a load balance network and you

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can use different parts of the network

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to share that load

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probably the most common place to find a

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wired mesh network is over a wide area

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network where you can create multiple

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links to other sites so that you can

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have a primary connection from one site

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to the other and then a backup or

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secondary connection that you can use if

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you run into problems

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when you start combining these different

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topologies together you create a hybrid

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network a hybrid network is more than

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one of these topology types all working

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together for example you might have

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three remote sites all connecting

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devices together using a switched

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ethernet or star network and then you

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may be connecting those together over a

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wide area network that uses a ring

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topology

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if you're using a wireless network you

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may be communicating in a number of

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different ways if you're using an access

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point you're probably communicating over

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an infrastructure connection this means

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that all of the devices on your network

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are communicating through an access

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point this is probably the most common

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way to use wireless connections but it's

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not the only way to communicate over a

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wireless link if you just have two

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devices and there's no access point that

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you can use you can connect directly

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from one device to another using ad hoc

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networking you don't need an access

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point or any other type of wireless

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infrastructure you simply have one

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device communicate directly to another

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device over this wireless connection

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and if you've added internet of things

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devices which are commonly wireless

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devices that control our lights our door

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locks or the air conditioning systems

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then you're probably using a mesh

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network where all of these devices can

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communicate to all the other devices

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simultaneously to create an

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interconnected mesh of communication

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between all of these iot devices

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one of the advantages of these mesh

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wireless networks is that it allows many

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devices to communicate to each other

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even if those devices are very far apart

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from each other this also allows the

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mesh network to self-heal so if you turn

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off one of those iot devices the

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remaining devices will self-heal and

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redesign themselves into a mesh network

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that will allow them to continue the

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communication

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you