Reviewer: Charles Perkins Review result: On the Right Track [Please excuse if this is a duplicate. I got an error from datatracker on my first attempt.] Overall comments: I think that some important techniques for energy efficiency deserve mention or significant enlargement: - Packet bundling - Data aggregation - Power management / range reduction - Fragmentation is more energy-efficient at lower layers than at higher layers - Compression, on the other hand, is more efficient at higher layers, particularly before encryption. The document needs a concise statement of purpose. Maybe insert the following after the first paragraph of the Introduction: In this document we describe techniques that are in common use at Layer 2 and at Layer 3, and we indicate the need for higher-layer awareness of lower-layer features. Also in the introduction, some discussion is needed about cross-layer design. Is cross-layer design in scope for the [lwig] Working Group? In figure 1 and elsewhere, it should not be assumed that RPL is the only choice for routing in energy-efficient networks. So, for instance, "RPL" could be replaced by "RTG" in Figure 1. Shouldn't there be an entry for synchronized reception in Figure 2? Isn't Figure 2 actually a table, and thus should be labeled Table 1? Section 3.3 (Throughput) does not seem to add much if anything to the discussion. The conclusion about the trade-off is quite obvious. Particularly in section 3.5.2, but also elsewhere, some examples would be very helpful. Section 6.3 (CoAP timers) seems to be only about one timer. Are there more? What about interactions with TCP timers, etc.? Section 7 should be entitled "Summary and Conclusions". In section 7, it would be nice to offer cross references for each conclusion, referring the reader to the relevant section of the document. Each conclusion should follow from some previous section of the document. Unfortunately that currently isn't quite the case. The citation [Announcementlayer] does not appear in the body of the article. There are weird line breaks appearing at certain random points in the document. I have editorial suggestions and corrections which I will supply as an rfcdiff file under separate email. Regards, Charlie P.