On page 70 of the Cisco Press BSCI Official Exam Certification guide there is a sentence.
"EIGRP uses split-horizon, which says that a router should not advertise a network on the link from which it learned about the network"
I'm a little confused as to what they are defining "learned" as. Is this learned as in, heard it from a neighbor? Or is it learned as in, used the route for the routing table?
Here is my scenario.. Router A is connected to Router B and Router C. Router D is also connected to Router B and router C. Lets say that Router D is announcing 172.16.1.1/24 to both routers B and C. Both of those routers will then announce that route to router A.
So router A has "heard" of the 172.16.1.1/24 route from both routers B and C. Does that mean that router A will not announce the 172.16.1.1/24 network to routers B or C?
Does it mean that it will announce the 172.16.1.1/24 route that it receives from Router B to router C and vice versa?
Hope someone can clear this up..