Original subtitles

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Administrative distance is then used as a tie breaker

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to determine which way to go when multiple routing protocols

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tell the router to go different ways.

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as an analogy, administrative distance is used as a tie breaker

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to determine which way to forward the traffic

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if OSPF says go left and EIGRP says go right

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the router uses administrative distance

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to determine which routing protocol it believes most.

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Technically, what happens is that the routing protocol

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with the lowest administrative distance is more believable

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and its routing information is inserted into the RIB

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or Routing Information Based or routing table in preference

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of other routing protocols that have a higher administrative distance

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so EIGRP has a lower administrative distance than OSPF.

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EIGRP has an administrative distance of 90

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OSPF has an administrative distance of 110

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so internal EIGRP would be preferred over OSPF.

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So the lower the administrative distance

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the more believable a routing protocol is

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you cannot believe anyone more than yourself

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so a router will believe routes that it originates

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above routes received from neighboring devices.

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A directly connected interface has a believability factor

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or administrative distance of 0.

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A static route configured to a next hop IP address

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has an administrative distance of 1.

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When a static route is configured to a directly connected interface

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it is deemed to be directly connected

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and therefore has a believability factor or administrative distance of 0.

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The reason why static routes have such a low administrative distance

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is that the router believes that you know more than other routers do.

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You as the administrator are supposed to know what you're doing

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and thus the router believes you more than it believes

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routes received via routing protocols such as OSPF or EIGRP.

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EIGRP has administrative distance of 90 for internal routes

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those are routes that originated in EIGRP and will not be redistributed

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or taken from a different routing protocol and then put into EIGRP.

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OSPF has an administrative distance of 110

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RIP has an administrative distance of 120

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and unknown routes have an administrative distance of 255

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as you can see EIGRP has a lower administrative distance than RIP does

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and that’s because EIGRP is a better or more powerful routing protocol.

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EIGRP will take bandwidth and delay into account when determining the best route.

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RIP only uses hop count

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so EIGRP seems to be better than OSPF which is better than RIP.