Thanks for this document! Please see my comments below.

Best,
/Marco


[General]

* Based on the guidelines from RFC 7322, the "Acknowledgements" section should be unnumbered and placed between the "References" section and the "Authors' Addresses" section.

* It is worth mentioning upfront that "capacity" refers to "link capacity" in terms of experienced bit rate. This becomes explicit only in Section 5.1, when discussing "Scalable throughput."


[Abstract]

* The three components of the L4S architecture include "protocol features that allow network elements to identify L4S traffic".

   The protocol in question becomes evident in Section 2 as ECN. The abstract can already mention that, e.g., as "features of the Explicit Congestion Notification (ECN) protocol that allow ..."


[Section 1]

* "With some transport protocols, namely TCP and SCTP, the sender has to check for suitably updated receiver feedback, whereas with more recent transport protocols such as QUIC and DCCP, all receivers have always been suitable."

   The first part of the sentence focuses on checking feedback from receivers, while the second one on the actual receivers. Does the second part actually mean "... feedback from all receivers is always suitable" ?
 

[Section 2]

* "... as the protocol to identify to the network which packets are L4S and which are Classic."

   This should be something like "... as the protocol that allows the network to identify which packets are L4S and which are Classic."
 
 
[Section 5.2]

* "... as opposed to TLS over UDP"

   Do you mean "TLS over TCP" or rather "DTLS over UDP"? Or instead the use of TLS for securing UDP-based transports such as QUIC?
 

[Nits]

* Section 3: s/low enough not build/low enough to not build

* Section 4.3: s/specifies that requirements that/specifies the requirements that

* Section 5.1: s/because it assume/because it assumes