Change:
phase (racing). Candidate Protocol Stack: One Protocol Stack that can be used by <del> an application for a connection, of which there can be several. Candidate Protocol Stacks are identified during the gathering phase (gathering) and are started during the racing phase (racing). </del> <ins> an application for a Connection, which there can be several candidates.  Candidate Protocol Stacks are identified during the gathering phase (gathering) and are started during the racing phase (racing). </ins> System Policy: Represents the input from an operating system or other global preferences that can constrain or influence how an

Discussion:
Thought to address all listed (and related) issues
These are bunched together, and likely could be addressed by one PR: Section 2, right below Figure 2: "The Transport Services API [I-D.ietf-taps-interface] defines the interface for an application to create network connections and transfer data." => Should this be "Connections" instead of "network connections" ? Section 2.1, paragraph 2, last line: "... made explicit in sockets." seems strange. Should this be "in the sockets API." ? Section 2.2 paragraph 1, this sentence: "While TCP does indeed provide the ability to send and receive data as streams, most applications need to interpret structure within these streams." Two issues here. First, I would switch to singular because TCP is not a multi-streaming protocol. I.e., change this to: "While TCP does indeed provide the ability to send and receive data as a stream, most applications need to interpret structure within this stream." Second, is "stream" a known concept? I don't think it's defined in this document, and I'm a little unsure because, even when using singular, someone might read "stream" and think of "one stream out of several, in a multi-streaming protocol". Maybe this is nit-picking, but if you agree, I would prefer to replace "stream" with "data stream", or having a definition of "stream" and capitalizing it (but then the definition would have to appear before the first use of this term...) GF: Data Stream Seems good. Next paragraph: double "provide" in: "Providing a message-based abstraction provides many benefits, such as:" - I suggest to replace the second with "has". In the following item list, I would remove the third item: "the ability to manage dependencies between messages, ..." While it is true that a message-based abstraction enables this, a reader of this document might get the impression that the TAPS system defined in the interface draft offers this specific functionality. It really doesn't, it would still have to be implemented on top of it. For this reason, this item strikes me as a bit misleading, and I think it should be removed.

Section 3, paragraph 2: "it can provide access to multiple sets of protocols and protocol features" - remove "sets of", this adds an unnecessary level of indirection here. I guess the transport property profiles in interface, section B.2 would be such sets, but still... Last paragraph before section 3.2: "Applications using a Transport Services system interface are REQUIRED to be robust to the automated selection provided by the system." - why say "system interface" here all of a sudden? This gives an impression as if there were two things: the API, and then perhaps also a separate "system interface". I'd rather replace this with "API". Last paragraph of section 3.4: "In normal use, a Transport Services system SHOULD result in consistent protocol and interface selection decisions for the same network conditions given the same set of Properties." Isn't this too restrictive? It prohibits a Transport Services system from improving. I would change this to: "In normal use, a given version of a Transport Services system SHOULD result in consistent protocol and interface selection decisions for the same network conditions given the same set of Properties." Section 4.1.5: "For example, a Message can be marked with a Message Property indicating that it is the final message on a connection if the peer sent a TCP FIN." I would stop this sentence after "on a connection." - or is it just me misunderstanding something? I thought (and -interface section 9.1.3.5 seems to agree with me) that the idea of "final message for TCP" really is that setting the property means that THIS message that I'm sending gets a FIN flag. Why would a FIN from the peer make me set this property? FWIW I could go on sending more data, and use this property much later? Section 4.1.7, item 1: "end of stream in the ..." - see above for a discussion of the word "stream". Section 4.2, item 5: "One Protocol Stack that can be used by an application for a connection, of which there can be several." => I believe it should be "Connection" here, not "connection". Section 4.2.2, first sentence: "or some combination of all of these" - should this be "or using some combination of all of these" ?

This is mentioned in another Issue: Section 1.2, item 4: About the last sentence in item 4, see: URL One other review comment might need discussion prior to resolving... and will be in the next issue