This document has been reviewed as part of the transport area review team's ongoing effort to review key IETF documents. These comments were written primarily for the transport area directors, but are copied to the document's authors and WG to allow them to address any issues raised and also to the IETF discussion list for information. When done at the time of IETF Last Call, the authors should consider this review as part of the last-call comments they receive. Please always CC tsv-art@ietf.org if you reply to or forward this review. I have not identified any transport related issues. To improve readability, you might want to * resolve acronyms on first occurence like CDN, CDNI,... * Remove section 1.1, since the introduced abbreviations are not used in the text. * add a graphical representation of the involved nodes and the messages being exchanged between them Typos: * Section 3: the uCDN provide a fallback -> the uCDN provides a fallback * Section 6: Nir B. Sopher -> Nir B. Sopher (no double space after period) * Section 6: Kevin J. Ma -> Kevin J. Ma (no double space after period)