Hmmm....would that make any difference, security wise, do you think if the 2820vn is behind the 2860?
I must admit I don't like the thought of keeping a router in use if it won't receive any more patches, ideally.
Going back to the original idea of retiring the 2820vn, I wonder if its possible to disable the VOIP bit of the 2860vn+ ? I've read you can do that, as well as reassign the SIP ports on other routers, but not had it confirmed on this model. That way I could re-enable when/if needed.
Seems there's few users of this model as yet as there seems not to be very many posts out there concerning it.