EIGRP best path selection with multiple successors

So, the new EIGRP "add-path" feature is intriguing to me as documented here
http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_eigrp/configuration/xe-3s/ire-add-path.html

As we know, EIGRP can indeed have multiple equal cost paths. In that case,
we will see more than one successor in the EIGRP topology table. However,
only one is actually sent to EIGRP neighbors by default, as the article
points out.

In certain DMVPN situations, this does not allow spoke to spoke load
balancing, hence the point of the add-path feature as explained.

All that is well and good, but I couldn't help asking myself as I was
reading "wait a minute, by default without all this, which successor would
it send?"

I have spent some time googling around and such and have labbed some things
up, but have not got a definitive answer. Anybody know?

In my lab test I had frame-relay hub and spoke network setup. The spokes
are both connected to the same ethernet segment and I had them redistribute
that ethernet segment into EIGRP with the same metric, but using different
route tags. My initial experiments seemed to indicate that the successor
sourced from the neighbor with the lowest IP address were sent upstream to
other EIGRP neighbors.

-- 
Regards,
Joe Astorino
CCIE #24347
http://astorinonetworks.com
"He not busy being born is busy dying" - Dylan
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