Telechat Review of draft-ietf-mops-treedn-05
review-ietf-mops-treedn-05-intdir-telechat-pignataro-2024-07-20-00

Hi!

Review of       draft-ietf-mops-treedn
Type    Telechat Review
Team    Internet Area Directorate (intdir)
Reviewer        Carlos Pignataro

This document describes TreeDN, a tree-based CDN architecture designed to
address  scaling challenges of live streaming to mass audiences. This is
achieved through Source-Specific Multicast (SSM), including PIM-SSM, and
tunneling or overlays based on Automatic Multicast Tunneling (AMT).

The overall architecture and document seem clear and largely complete. At times
it might read a bit marketing-ish (e.g., S3, is this solving for all
multicast?), though the technical details are comprehensive. This is an
Informational-targeting document.

From a document clarity perspective, there's an opportunity to earlier on
summarize what the architecture is. Interestingly, IDnits flags that there is
no "Introduction" section. While I do not believe an Introduction is mandatory,
early text describing TreeDN will help. Specifically, something like:
   "TreeDN is essentially the synthesis of SSM plus overlay networking
   technologies like AMT to deliver traffic to receiving hosts on
   unicast-only networks, or directly natively on-network when there's support
   for support multicast."

From an Int-Area perspective, I feel some of the coverage of tunneling +
multicast is lacking. For example, specifically, generation, treatment,
defaults, throttling, processing of ICMP Error messages. The document does not
include the acronym "ICMP", yet I believe it is important particularly for AMT.

Further, combining this Int-Area perspective with some added operational
aspects, manageability (from defaults to toolset) seem also highly lacking.

I hope these are clear and useful.

Thank you!

Carlos.