This document has been reviewed as part of the transport area review team's ongoing effort to review key IETF documents. These comments were written primarily for the transport area directors, but are copied to the document's authors and WG to allow them to address any issues raised and also to the IETF discussion list for information. When done at the time of IETF Last Call, the authors should consider this review as part of the last-call comments they receive. Please always CC tsv-art@ietf.org if you reply to or forward this review. I have found the document to be clear and readable. I could not find any transport specific issue that inside the document that would need to be discuss. From a transport viewpoint, the classical MTU concerns are valid, but they mainly concern RFC8300 and not specifically this document. Concerning ECMP, a point of attention when deploying stateful functions in a network where ECMP is used would be to ensure that transport flows would be mapped to the same instance of a stateful function. This is probably already discussed in other documents related to service function chaining.