I need design assistance with bgp & ospf

[gavin han]

I need design assistance with bgp & ospf.

1. site-2 should use green link as primary to reach site-1 and red link as back to reach site-1.
2. site-3 should use its green link as primary to reach site-1.
3. site-2 and site-3 use their directly connected link as primary to reach each other and traverse through site-1 to reach other if site-2 <-> site-3 links fail.
4. sd-wan should be used as tertiary. i.e. if site-1 and site-2's links to site-1 fails then they should use sd-wan to reach site-1?

how to accomplish this without causing any loops?

[gavin han]

could someone assist please.

[rasmus.elmholt]

Hi

I would do all inter-site routing using eBGP that way you have full control of the path selection.
Otherwise you would have to change AD and other default values.
You will automatically avoid routing loops if you run an IGP inside each side and eBGP between them.

[nazimkha]

Instead of iBGP you can run OSPF and do mutual redistribution between BGP and OSPF at the edge. You can use route aggregation and filtering for the received and advertised routes

[G Money]

Hire a consultant.