Original text:
compression-induced head-of-line blocking.  See that document for additional details.  An HTTP/3 implementation MAY impose a limit on the maximum size of the message header it will accept on an individual HTTP message.  A server that receives a larger header field list than it is willing to

Reviewer comments:
This
The transport draft talks about QUIC being resilient to NAT rebindings. However, if a QUIC server is behind an L3 load balancer which simply routes based on 5-tuple, then connections to this server will (likely) not survive rebinding. I couldn't find any language which addressed whether such a deployment was "OK" or not. I think that since this load balance does not support NAT binding resilience, it is implicitly "bad" according to the draft, but others might disagree. In any case, I think there should be text to address this. Note, if the server advertised a preferredaddress which routed around the load balancer, and if clients were required to use this address, then that could obviously work. But preferredaddress support is a SHOULD, not a MUST.
We did discuss this issue. Use of empty connection IDs and demultiplexing based on source addresses. The conclusion there was that this was OK: people could do that, as long as it was clear that what they were getting was not different than TCP. That is, we made it clear that if you don't use the identifiers that you control (your addresses, the connection ID), then you accept that you can't handle migration at all and connections will drop (well, unless you do something like trial decryption, which has some obvious scaling issues). The outcome of that discussion was captured in . Assuming that Ryan finds this answer satisfactory (and I haven't missed anything), then I suggest we just close this as a duplicate of .
I don't think this captures Ryan's concern: when the server is using a non-zero CID and also is behind 4-tuple routing. I think he's looking for a section of text to coherently describe what you have to do here: send either disablemigration or preferredaddress; or forward packets between servers; or either don't use a common stateless_reset key, or put client address/port in the reset token. This is sort of ops-drafty but there real requirements on servers to behave in a secure way. I think someone with full command of the transport draft would figure this out, but it is not clearly stated anywhere.
I agree with Martin Duke and the language he suggests makes sense to me.
This does feel a bit ops-drafty to me, but I'd be happy to review a PR.
NAME notes that: We need to normatively reference 7540 for this capability.
See also discussion thread starting at URL Hi, RFC7540 allows crumbling cookies for compression efficiency with HPACK. However, neither quic-http nor quic-qpack drafts mention cookies or crumbling. Is it considered safe for a QPACK implementation to crumble cookies before compression and concatenate them after decompression? If so, should the draft include clarification on this? Thanks, Bence

Revised text:
compression-induced head-of-line blocking.  See that document for additional details. <ins> To allow for better compression efficiency, the cookie header field RFC6265 MAY be split into separate header fields, each with one or more cookie-pairs, before compression.  If a decompressed header list contains multiple cookie header fields, these MUST be concatenated before being passed into a non-HTTP/2, non-HTTP/3 context, as described in HTTP2, Section 8.1.2.5. </ins> An HTTP/3 implementation MAY impose a limit on the maximum size of the message header it will accept on an individual HTTP message.  A server that receives a larger header field list than it is willing to