I am the assigned Gen-ART reviewer for this draft. The General Area Review Team (Gen-ART) reviews all IETF documents being processed by the IESG for the IETF Chair. Please treat these comments just like any other last call comments. For more information, please see the FAQ at . Document: draft-ietf-core-echo-request-tag-11 Reviewer: Ines Robles Review Date: 2020-12-02 IETF LC End Date: 2020-12-02 IESG Telechat date: Not scheduled for a telechat Summary: This document specifies the Echo option that enables a CoAP server to verify the freshness of a request or to force a client to demonstrate reachability at its claimed network address, and specifies also the Request-Tag that allows the CoAP server to match block-wise message fragments belonging to the same request. Also, this document updates RFC7252 with respect to the client Token processing requirements. The document is well written, I have some minor questions/comments below. Major issues: None. Minor issues: None. Nits/editorial comments: 1.- It would be nice to have the definition of Freshness into the terminology section. 2.- Figure 1 and Figure 4 have two columns named "U" (Unsafe), is that Ok?, or should one of these columns be deleted/renamed? 3- Page 26: Please expand IV. Thank you for this document, Ines.