We have two Data centres in different locations, I need to put together a resilient design over WAN links which should failover to either links.one is MPLS other is Point to Point
Router A and Switch B are MPLS running ibgp
Switch A and Switch C are point to point
How Router A and Switch A need to be connected i-e routing protocol etc?
How Switch B and Switch C need to be connected i-e routing protocol etc?
end goal is to use eigrp as primary route and iBgp as backup.
Many Thanks any help is appreciated.
from my understanding to your network and diagram that you wan DC1 and DC2 to communicate using the EIGRP path between Switch and C and Switch A as primary path and MPLS/BGP as backup
this is simple and can be done using many ways but it is better to keep it simple not complicated and you need to be careful because this topology may cause routing loop if there is any config/deign error
my recomendation to do the bellow
router A and Switch B will be Runing BGP ( i believe it will be EBGP not iBGP if you are going to run/exchange the BGP with a MPLS Service provider ! ) assuming it is EBGP
configure the BGP peering over the MPLS path, and at the same time configure EIGRP on router A, Switch A, B, C but do not include the interface connected to the MPLS on each router A and Switch B
now to make sure the EIGRP always preferred reduce eigrp administrative distance to somthing lower than 20
let say 18 including external eigrp
this way you will make sure router A and Switch B will always chose EIGRP path and if the route not seen through EIGRP then it will use it through any other source ( BGP in your case if th elink between Switch C and A are down )
now the end to end EIGRP ok over Switch A and C between the two DCs
now you need to advertise networks of each local site over BGP for back path
you can redistribute EIGRP into BGP or use network command to advertise network by network
i recommend you to use the network command to selectively advertise the networks that you want to be used over MPLS/BGP path as back up
for example if 10.1.1.0/24 is learnd by Router A from Switch A via EIGRP
under bgp config you can use the command network 10.1.1.0 mask 255.255.255.0
Switch B will learn this through Switch C over EIGRP with administrative distance of 18 ( changed above ) and through EBGP as 20 ( if its iBGP will be AD as 200 ) and thus EIGRP path will be chosen
last fine step is to redistribute BGP route into EIGRP for route coming from other DC over BGP to be used in the case of failover situation but here make sur ewhen you redistribute you increase the delay/bandwidth when you use the redistribute command so that form EIGRP point of view it will be less preferred and also you can use route-map to filter what need to be redistributed
if helpful Rate