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EIGRP Question.

Looking at this, Could someone please look at my notes in parentheses and tell me if I got this correct?

If the AD (advertised distance) is less than the FD (feasible Distance) of the best route, then it is a feasible successor. The successor is the best route and is put into the IP routing table.

Langley#show ip eigrp topology P 10.1.2.0/24, 1 successors, FD is 768 via 10.1.3.1 (768/256), Serial0 (This is the successor, currently used route) via 10.1.5.2 (1280/256), Serial1 (256 < 768, this is a FS).

P 172.16.90.0 255.255.255.0, 2 successors, FD is 0 (am I correct in assuming that the FD is really 46251776?) via 172.16.80.28 (46251776/46226176), Ethernet0 (This is the successor) via 172.16.81.28 (46251776/46226176), Ethernet1 (This is the successor) via 172.16.80.31 (46277376/46251776), Serial0 (not a FS, as the AD = FD)

Thanks crzzy1

Reply to
cozzmo1
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You are correct. Not sure why the FD is reported as 0 for the 172.16.90.0 route. Could be a bug in your IOS version.

Reply to
thrill5

I think that perhaps since this has 2 load balancing successors which both have equal cost AD and FD, the route just has an incorrect zero for the FD. I wonder if you had unequal cost successors (using the variance command) if they too would have an FD of zero then.

P 172.16.90.0 255.255.255.0, 2 successors, FD is 0 (am I correct in assuming that the FD is really 46251776?) via 172.16.80.28 (46251776/46226176), Ethernet0 (This is the successor) via 172.16.81.28 (46251776/46226176), Ethernet1 (This is the successor)

Reply to
cozzmo1

One other question,

Why does the last entry show up (via 172.16.80.31)? Wouldn't you need "#show ip eigrp topology all-links" in order to see that which is not a feasible successor? and yet, there it is.

According to my text, routes that are not successors or feasible successors are not shown in #show ip eigrp topology yet these routes can be found in #show ip eigrp topology all-links

thanks, crzzy1

Reply to
cozzmo1

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