I have reviewed this document as part of the security directorate's
ongoing effort to review all IETF documents being processed by the
IESG.  These comments were written primarily for the benefit of the
security area directors.  Document editors and WG chairs should treat
these comments just like any other last call comments.

The summary of the review is Ready with nits.

This document extends OSPF for use with tunnels. As mentioned in the 
security considerations, an attacker who can modify routing information 
can cause packets to be misdirected or dropped. However, that seems to 
be the general nature of routing attacks. I don't know if this document 
makes such attacks any more likely or more severe, but it would be nice 
to see a bit more discussion of that in the security considerations. 
E.g., are OSPF attacks without tunneling less severe because of some 
limitation on where packets can be forwarded, while tunneling makes it 
easier to forward packets to anywhere on the Internet? Or is that not 
the case? (I'm not very familiar with OSPF or with the environments it's 
typically used in.)