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 draft describes how to extend IS-IS and OSPF routing protocols to allow signal of loss of reachability to an individual prefix. The draft relies on existing mechanisms in these protocols and on two new flags. Existing security mechanisms for these routing protocols are advised to be used to reduce the risk of injecting false unreachability advertisement by an attacker.

I think the draft is ready.