route poisoning and reverse poisoning

Hi all,

I am studying for my ccna and due for my exam in a few weeks. I am a bit confused about the difference, if any, between route poisoning and reverse poisoning and was wondering if someone could explain the difference please? I have searched the matter but still carry confusion after reading differing explainations. Thank you,

Regards, Vos

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route poisoning and reverse poisoning are routing loop prevention techniques used by distance vector routing protocols.

"Poison reverse allows routers to break the split horizon rule by advertising information learned from an interface out the same interface. However, it can advertise routes learned from an interface out the same interface with a 16 hop count, which indicates a destination unreachable, "poisoning" the route. Routers with a route with a better metric (hop count) to the network ignore the destination unreachable update."

route poisoning is setting a route's metric to infinity (i.e. max hops

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poison reverse is the process of breaking the split horizon rule and sending a poisoned route back over the same interface from which it was learned

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Ahh that clears up my confusion.

Thank you for your time Merv. :)

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