So this may be just me missing something due to lack of sleep or oversight, but I see an IP address in the intial configs for the switch vlan 47, and for R4 int fa0/0 on vlan 47. Any reason we can't just bring up a simple ospf adjacency? I did and it worked but when I read we can't "add an ip address" I was thinking I missed something. Then in the answer guide it showed a tunnel. Any reason for this? Is this something that was corrected after the fact?