where the EIGRP stub should configure and the difference in FVRF DMVPN

[rookie R]

Hi all!

Here is the topology:

I use FVRF to configure the DMVPN, the overlay and underlay of the Hub are both in the global routing table, and the underlay of the Spokes is in vrf UNDER, the overlay of the spokes is in the global routing table. I use EIGRP as the routing protocol in the overlay.R4, R5, and R6 are eigrp neighbors. R4 generates a default route to its spokes, both R5, R6, and R8 receive that default route. Switch 1&2 are both L3 switches that run EIGRP too, and both of these switches form eigrp neighbors with R5 and R6.The status of the dmvpn and eigrp are both up.

My questions are:
1. what is the difference between configuring the R5&R6 as the eigrp stub area and switch1&2 as the eigrp stub area?  Will it affect R5&R6 as backup outlets for underlay and overlay? The only difference I can tell is if the stub is in R5&6, there will be no query sent to this branch, and there will be if the stub is in switch1&2. 

2. I don't need to configure the eigrp stub area in Branch 2 because R8 doesn't have other eigrp neighbors in the branch, EIGRP query only sends to those that have an eigrp neighbor, right?

[MHM Cisco World]

For dmvpn we config eigrp stub in dmvpn router which make some prefix hidden from hub (DC routers) or other spoke.

I dont see any meaning of config it in SW' in end you need to make edge router know prefix behind SW.

MHM

[rookie R]

I have another thought about this question. There may be other switches in Branch 1 in the future, switches 3 & 4, connecting to the R5 & R6 just like switches 1 & 2. So the difference in configuring the stub on the switches instead of the routers is that R5 & R6 can receive queries when there are other switches that are in another network segment. Does my thought make any sense?

[David Ruess · Accepted solution]

Hello,

If you configure EIGRP STUB on R5/R6 then R4 will not send a query to them. However if there are subnets on your switches then you will need to configure leak-maps for the STUB configuration in order to advertise them along with the default of connected and summary routes.

Secondly, R4 WILL Query R8 but then R8 will send a Reply right back if it has no EIGRP neighbors. If you want to prevent this you would configure R8 as a STUB router.

Hope that helps

-David

[MHM Cisco World · Accepted solution]

I dont get full your Q but it open other window 
if I config Spoke as stub are the router behind this spoke learn prefix from other Spokes ?
NO 
we know we use Stub to reduce query but that not meaning we make network reachability issue. 
I config R2 as stub summary in DMVPN, and you can see the R3 behind it dont know the prefix of other Spokes at all. 

why It open new window? are the stub is per interface or per router, it per router so stub in Spoke R2 is effect both DMVPN and R3 (router behind R2).
so this can solve by making R2 advertise default route toward R3 and making leak-map instead of using stub summary

MHM