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. This informational document describes applicability of the Babel routing protocol in terms of existing deployments. It recommends using one of two security mechanisms defined for Babel (HMAC vs. DTLS). I did not review the referenced docs for HMAC/DTLS, but assuming there are no issues with those docs, I see no security issues with this document.