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-avtcore-multi-party-rtt-mix-14 Reviewer: Peter Yee Review Date: 2021-05-05 IETF LC End Date: 2021-05-03 IESG Telechat date: Not scheduled for a telechat Summary: This draft specifies updates to RFC 4103 to allow real-time text mixing for both multiparty-aware and multiparty-unaware participants. It has some minor issues that should be addressed before publication. [Ready with issues] Major issues: None Minor issues: Page 7, 1st block, 13th sentence: what constitutes a “reasonable effort”? It might be best to drop this sentence. Page 7, 2nd block, 2nd sentence, “300 ms”: would it make sense to append “period” or “timeout” after this value? Page 13, section 3.4, 2nd paragraph, 1st sentence: in regards to “only part”, how is this calculated? Page 15, section 3.12, 2nd paragraph, 1st sentence: The placing of all available redundant levels in the packet is presumably subject to a maximum packet size or the “CPS” limit, if there are obnoxious levels of redundancy specified? Page 17, section 3.17.2, 4th paragraph, 2nd sentence: “SHALL prefer” seems odd. It doesn’t say that the marking will actually be done. It’s just preferred. If you’re not going to require the marking in that sentence, then perhaps change “SHALL” to “SHOULD”. Page 19, section 3.20, 2nd paragraph, 2nd sentence: I don’t find the “something specific” particularly enlightening. Like what? An identifier for the method? Page 27, section 4.2.2, 4th paragraph: can you elaborate on these “Integrity considerations”? Otherwise, it’s difficult to comply with the SHALL in any meaningful way. Page 33, 3rd paragraph, 1st sentence: any reason for the change from “T.140” in the previous and following paragraphs to “t140” in this one? Page 33, 6th paragraph: how is disappearance determined? Page 35, section 11, 3rd paragraph, 2nd sentence before creating a new sentence (see nits, below): I’m having troubles tying the adjective “secure” to each of the nouns in the sentence. It works for “signaling” and perhaps “media”, but for “authentication”, one sort of assumes that authentication mechanism is secure and helping to provide the security. Perhaps you could reword that sentence? Nits/editorial comments: General: Change “multi-party” to “multiparty” throughout the document. While we are a bit inconsistent about that particular hyphenation within the IETF, all major dictionaries I sampled spell this as a single, non-hyphenated word. Append a comma after each instance of “e.g.”. Change “multiparty aware” to “multiparty-aware” throughout the document except in two cases where you “multiparty awareness”, which should be left alone. These are located in section 4.2, 1st paragraph, 1st sentence and section 6.1, 2nd paragraph, 2nd sentence. Change “fall-back” to “fallback” in a few places in the document. Both uses are found in the document. Change “RTP-mixer based” to “RTP-mixer-based” throughout the document. Change “multiparty capable” to “multiparty-capable” throughout the document. Delete periods at the end of section/subsection titles, e.g., section 6.2. Specific: Page 1, Abstract, 1st sentence: I’d rewrite it in the active voice as: “This document provides enhancements for RFC 4103 real-time text mixing suitable for a centralized conference model that enables source identification and rapidly interleaved transmission of text from different sources.” Page 1, Abstract, 3rd paragraph, 1st sentence: insert a hyphen between “multiparty” and “coded”. Page 5, 3rd paragraph, 1st sentence: I think I would change “in” to “at”. Page 5, 7th paragraph, 3rd sentence: delete “any”. Change “way” to “ways”. Page 6, section 1.1, 2nd paragraph: insert “are” before “as”. Page 6, section 1.1, “WebRTC” term: change “web based” to “web-based”. Insert “real-time” before “communication”. Page 6, “DTLS-SRTP” term: delete “stands for security”. Insert “is a DTLS extension for use with SRTP/SRTCP” before “specified”. Page 6, “multiparty-aware” term: change “stands for” to “describes”. Append a comma after “real-time” before “separated”. Append a comma after “source”. Page 6, “multiparty-unaware”: change “stands for” to “describes”. Pages 7 and 8: delete the period after each of the non-indented lines, e.g., at the end of “Multiple RTP streams, one per participant.” Page 7, 1st block, 4th sentence: change “end to end” to “end-to-end”. Page 7, 1st block, 11th sentence: append a comma after “participant”. Delete the following “and”. Insert “with” before “no”. Page 7, 1st block, 14th sentence: change “implementation” to “implementations” and delete “technologies” unless you really want the problem is in regards to technologies and not particular implementations. Page 7, 1st block 15th sentence: change “made” to “led to”. Insert “being” before “only”. Page 7, 2nd block, 1st sentence: insert “a” before “shorter”. Insert “the” before source”. Insert “the” before “CSRC”. Append field after “CSRC”. Page 7, 2nd block, 2nd sentence: insert “a” before the quoted “text/t140”. Page 7, 2nd block, 3rd sentence: delete the whole sentence. Page 7, 2nd block, 6th sentence: move “with” before “receivers”. Insert “having the” before “default”. Page 8, 1st partial block, 2nd full sentence: insert “it” before “corresponds”. Page 8, 1st full block, 6th sentence: change “be varying” to “vary”. Page 8, 1st full block, 9th sentence: change “while” to “When”. Page 9, section 1.3, 1st paragraph, 3rd sentence: change “calltaker” to “call taker”. Change “observing” to “to observe”. Page 11, section 2.4, 3rd paragraph: append a comma after “CSRC-list”. Page 12, section 3.1, 4th paragraph: change “From other aspects” to “In other regards”. Page 13, section 3.4, 1st paragraph, 3rd sentence: insert a hyphen between “10” and “second”. Page 13, section 3.4, 1st paragraph, 4th sentence: delete “a” before “good”. Page 13, section 3.4, 2nd paragraph, 1st sentence: insert “SHALL be” before “sent”. Insert “the” before “end”. Page 13, section 3.4, 2nd paragraph, 2nd sentence: Append a period at the end of the sentence. Page 13, section 3.4, 3rd paragraph: change “in” to “as”. Page 13, section 3.6: insert a hyphen between “locally” and “produced”. Append “text” after “produced”. Page 14, 1st paragraph, 3rd sentence: delete the comma after “T140blocks”. Page 14, section 3.10, 1st paragraph after the bullet points, 1st sentence: insert “the” before “time”. Page 15, section 3.11, 2nd paragraph: append a comma after “switch”. Change “poulated” to “populated”. Page 15, section 3.12, 1st paragraph, 1st sentence: insert “the” before “next”. Page 15, section 3.12, 1st paragraph, 2nd sentence: insert “the” before “next”. Page 15, section 3.12, 2nd paragraph, 2nd sentence: change “number” to “level”. Page 16, section 3.14, 1st paragraph, 1st sentence: delete an extraneous space after “(“. Page 16, section 3.14, 1st paragraph, last sentence: insert “self-sourced” before “data”. Delete “that it is source of itself”. Page 16, section 3.16, 1st paragraph, 1st sentence: append a comma after “CNAME”. Page 17, section 3.17.2, 1st paragraph, 1st sentence: insert “The receiver SHALL monitor”. Change “The” to “the”. Delete “SHALL be monitored”. Page 17, section 3.17.2, 2nd paragraph, 2nd sentence: append a comma after “case”. Insert “the receiver SHALL create” before “a t140block”. Delete “SHALL be created”. I’m suggesting but not certain that you might want to change “and assigned” to “associated with”. Page 17, section 3.17.2, 4th paragraph, 1st sentence: change “if” to “whether” if you are amenable to that wording. Page 18, 2nd paragraph: delete an extraneous blank line before this paragraph. Page 18, section 3.18, 1st sentence: insert a hyphen between “10” and “second”. Page 19, section 3.19, 1st sentence: insert “the” before “session”. Insert “the” before “media”. Page 19, section 3.19, 2nd sentence: insert “the” before “media”. Consider deleting “security by”. Page 19, section 3.19, 5th sentence: change “is” to “are”. Page 20, section 3.21, 4th sentence: append a period after “etc”. Page 21, 1st partial paragraph, 1st full sentence: insert “a” before “dropped”. Page 21, 1st full paragraph, 1st sentence: delete an extraneous space after “(“. Where the word “area” occurs, would that make more sense as “buffer” or “queue”? Page 21, 1st full paragraph, 2nd sentence: insert “initial” before the first “text”. Page 22, 1st paragraph, 2nd sentence: change “in” to “due to”. Page 22, 2nd paragraph, 1st sentence: insert “packets” before “103”. Delete the comma after “103”. Page 22, 2nd paragraph, 2nd sentence: there appears to be an adverb missing before “the”. Perhaps “during”? Page 22, 3rd paragraph, 2nd sentence: change “21040” to “21060”. Page 22, 4th paragraph, 1st sentence: change “needs” to “need”. Page 22, 4th paragraph, 2nd sentence: change “21150” to “21160”. Page 23, section 4, 1st paragraph, 2nd sentence: delete “and”. Page 23, section 4, 3rd paragraph: consider changing “of” before “the text” to “conveyed in”. Page 24, 1st full paragraph, 3rd sentence: insert “a” before “replacement”. Page 24, 1st full paragraph, 4th sentence: change “just” to “the same”. Page 26, section 4.2, 3rd paragraph, 2nd sentence: insert a hyphen between “best” and “effort”. Page 26, section 4.2, 4th paragraph, 1st sentence: append a comma after “simulated”. Page 26, section 4.2, 4th paragraph, 4th sentence: change “is depending” to “depends”. Page 26, section 4.2, 4th paragraph, 5th sentence: change “switch” to “switching”. Append a comma after “can”. Append a comma after “example”. Page 26, section 4.2.1, 3rd sentence: append a comma after “keep-alive”. Page 27, 5th bullet point: insert “the” before “next”. Change “if even” to “even if”. Insert “a” between “for” and “word delimiter”. Page 28, section 4.2.4, 1st paragraph: insert “the” before “UTF-8”. Change “transform” to “transformation”. Page 28, section 4.2.4, “BEL”: change the comma after “session” to a period. Capitalize “provides”. Page 28, section 4.2.4, “NEW LINE”, 3rd sentence: insert “the” before “display”. Page 28, section 4.2.4, “CR LF”, 1st sentence: delete the comma after “supported”. Page 28, section 4.2.4, “CR LF”, 3rd sentence: insert “the” before “display”. Page 28, section 4.2.4, “INT ESC”, 1st sentence: insert “the” before “mode”. Page 28, section 4.2.4, “SGR”, 2nd sentence: insert “the” before “rendition”. Page 29, 1st partial sentence: insert a hyphen between “256” and “bytes”. Then change “bytes” to “byte”. Page 29, “BOM”, 1st sentence: insert “it” before “SHALL”. Page 29, “Missing text mark”, 1st sentence: change the comma after “apostrophe ‘” to a period. Insert “It” before “marks”. Insert “the” before “place”. Insert “the” before “stream”. Page 29, “SGR”, 1st sentence: delete the comma after “(SGR)”. Insert “the” before “status”. Page 29, “SGR”, 2nd sentence: change “originated” to “originating”. Page 29, BS, last sentence: change “not” to “be”. Page 32, section 6.1, title: drop the “e.g.” in the subsection title. Page 32, section 6.1, 2nd paragraph, parenthetical: perhaps you want “i.e.,” instead of “e.g.” here given that further down you put “TTYS” in another parenthetical as though it weren’t just an example but the only exemplar of this type of device under discussion. Page 32, section 6.1, 2nd paragraph, last sentence: delete “make”. Change “adaptions” to “adapt”. Delete “for” before “the functional”. Delete “(TTY)”. Page 32, section 6.1, 3rd paragraph: delete “(TTYs)”. Page 33, 2nd paragraph, 2nd sentence: insert “a” before “two-way”. Page 33, 3rd paragraph, 2nd sentence: insert “the” before “NAME”. Page 33, section 7: insert a hyphen between “multiparty” and “mixing” in this one instance of that term. Other uses of the term in the document should not be hyphenated. Page 34, section 8, 1st paragraph: I like the sound of the sentence better if you swap “valid” and “also”. That’s just me.  Page 34, section 8, 3rd paragraph, 1st sentence: insert a space between “second” and “(“CPS”)”. Page 34, section 8, 3rd paragraph, 3rd sentence: insert “an” before “RTP”. Regarding “excess”: in excess of what? Page 35, section 11, 1st paragraph, 1st sentence: append a comma after “pack”. Page 35, section 11, 2nd paragraph, 1st sentence: append a comma after “CNAME”. Page 35, section 11, 3rd paragraph, 1st sentence: I suggest inserting “emitting” before “a continuous”. Change the comma after “flow of text” to a period. Delete the following “or”. Change the rest of that sentence to read something like: “They may also send text that appears to originate from other participants.” I rewrote that because the malicious participants don’t themselves masquerade as text, although that might be a mildly amusing Halloween costume. Page 35, section 11, 4th paragraph: delete one of “section” or “Section”. You capitalize that term interchangeably, so it’s your choice. Page 35, section 12.1 (when discussing -14 only): change “Cucherawy” to “Kucherawy” unless we’re talking about someone else. Yeah, I know these will all be deleted upon publication, but it caught my eye. I have not reviewed the remainder of the change history entries.