EIGRP Equal Cost Load Balancing

Let's say I have R1 connected to R2 and R3 and R2 connected to R3 ( Triangle Connection) with the same Link Speed.
 for R1 to reach R2 it can go directly or it can go through R3 then R2
Well, are these considered Equal speed even though going   R1 going through R3 is an extra hop ?

What I mean , does EIGRP factors in the Hops or sees link as just one link disregarding the hops ?

Thanks
jskfanAsked:
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JustInCaseCommented:
EIGRP ignores hop count. Cost is relevant, that's what EIGRP metric is all about...
Except in that case that you mentioned - when there routers are directly connected.
The reason is... EIGRP route will be ignored for AD of directly connected routes is more reliable of AD of EIGRP, so in example that you gave ... only one path will be used. :)
jskfanAuthor Commented:
Which path ? the direct path or the path across another router ?
JustInCaseCommented:
Direct path will be used.
AD default values - so connected interface is more reliable than EIGRP, so EIGRP will not be considered in that case.
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jskfanAuthor Commented:
OK it was one case
in case there is 1 router in the way to the destination through one path and 2 routers in the way to the destination through other path. Which path will EIGRP takes ?
asavenerCommented:
EIGRP calculates the metric based on the path cost.  Path cost is calculated based on the bandwidth and delay of each hop.

So the answer to your question is "it depends."

If the one-router path is over a 56K line, and the two-hop path is over two 100 Mb links, then it will select the two-hop route.  If the bandwidth and delay on each link is equal, then the one-hop path would be preferred.

Now, there's a command that tells the router that two path costs are "close enough" to be considered equal-cost routes, so if there will be times when close-but-still-different-cost routes will still be considered to be equal cost routes.
JustInCaseCommented:
Advantage of EIGRP is that it don't hop count into consideration (as I said in my first post).
Roads\Time analogy:
To the same place you can go dirt road 2 * 1 km = 30 minutes, or take highway 5 * 5km = 10 minutes. If yu ask RIP for directions - RIP will point you to dirt road, EIGRP will point you to highway.
If both path have same time cost, let's say 30 minutes. RIP will still point you to dirt road, EIGRP will point you once  to dirt road, next time will point you to highway.

EIGRP ignores hop count.
asavenerCommented:
Direct path will be used.
AD default values - so connected interface is more reliable than EIGRP, so EIGRP will not be considered in that case.
This is true, but incomplete.  Addresses in the same subnet as the interface are directly connected.  All other addresses handled by the remote router will be routed based on the routing protocol.
JustInCaseCommented:
How did you manage to ignore from previous post.
Except in that case that you mentioned - when routers are directly connected.

Three routers R1, R2, R3 linked in triangle, two routes to the same network - one is directly connected, and one is not.
And also
 so in example that you gave

:)
asavenerCommented:
Pretty sure he meant two paths to destination network, one path with just one hop and one path with two hops.

On the one-hop path, the remote site's router interface is directly connected, but the subnets beyond the router are not directly connected.

Typically in a WAN, the point-to-point links just include the router interfaces.

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Don JohnstonInstructorCommented:
in case there is 1 router in the way to the destination through one path and 2 routers in the way to the destination through other path. Which path will EIGRP takes ?
Can you please provide a diagram of what you're asking about?
jskfanAuthor Commented:
Thank you
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