Reviewer: Magnus Westerlund Review result: Ready with Issues I have reviewed this document as part of TSV-ART task to review documents with potential transport related issues. I note that the document in its final recommendation regarding block sizes do consider MTU for reasonable size choices. What I am missing in Section 4 is the discussion of MTU as impacting this. From my perspective, it appears reasonable to: In Section 4.1 consider if the Block Size will interact with the MTU. Especially for block sizes that are a small fraction of the MTU, unless the block is chosen so that a multiple just fits the MTU, the block padding may cause unnecessary fragmentation for UDP based delivery. Also chosing a block size larger than the MTU of course forces one to always fragment. In Section 4.2 I think depending on the negotiated size, the downside is that it will commonly result in a consistent number of fragments reducing delivery probability. I haven't digged into the negotiation part about maximum response size. But, I assume that this is not necessarily chose based on MTU constraints, but other limitations in the system. Note that these comments only applies for datagram based transport without its own fragmentation mechanism, e.g. UDP.
