[c-nsp] SD-WAN design for large scale

[adamv0025 at netconsultings.com]

> daniel.dib at reaper.nu
> Sent: Tuesday, March 24, 2020 10:27 AM
> 
> Cisco SD-WAN doesn't use DMVPN, it uses OMP for control plane and IPSec
> for data plane.
> 
> Omar: Yes, by default you will have a full mesh of tunnels. It's easy to build
> Hub and Spoke topology if you want to. Often large organizations build
> regional Hub and Spoke where you traverse a Hub to go to another
> geographical region, such as EU to US etc.
> 
Is that the case really?
When we were reviewing sd-wan solutions from a number of vendors last year -my recollection is that hub and spoke or dual hub and spoke (but not multi-hub and spoke) was their go to topology and most of them didn't even considered full-mesh of tunnels between spoke sites until I asked.

If you consider what sd-wan is selling, its MPLS like QOE over cheapo Internet links - for which they need at least two (ideally more) links, then the number of tunnels is going to be n(n-1)/2 times the number of cheapo links to the spoke site.
   
 
adam