I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
by the IESG for the IETF Chair. Please treat these comments just
like any other last call comments.
For more information, please see the FAQ at
<https://trac.ietf.org/trac/gen/wiki/GenArtfaq>.
Document: draft-ietf-dots-architecture-15
Reviewer: Paul Kyzivat
Review Date: 2020-01-23
IETF LC End Date: 2020-01-27
IESG Telechat date: ?
Summary:
This draft is on the right track but has open issues, described in the
review.
General:
This is a very well written document! Even though I lack any knowledge
of the subject domain I was generally able to understand it.
I had trouble classifying some of my issues below. I wanted to make them
be questions. But in a review such as this it makes more sense to state
them as issues of clarity in the text, since the reader should ideally
not be left with questions.
Issues:
Major: 0
Minor: 5
Nits: 0
1) MINOR: Resource Ownership:
The 2nd paragraph of section 2.2.2 stresses that it is important for a
DOTS Server to verify that the DOTS Client owns the resources over which
it is requesting mitigation.
There seems to be quite a lot hiding behind that requirement. In
particular, how is the server supposed to be in a position to do that
verification? This seems to require that the server have access to
ownership information. While that may be easy in some cases (e.g., when
the server is operated by the ISP that assigned the resources to the
client), in other cases it could be hard. I'd like to see more
discussion of this.
2) MINOR: Scope and lifetime of sessions:
Section 3.1 states that a session can be a signal channel session or a
data channel session or both. I'm confused about the relationships here.
If a session can consist of both, how are they related? Is there some
state that ties them together?
Can a channel survive the loss and reestablishment of a TCP connection?
Or does the creation of a new connection create a new channel?
What is the act that creates a new channel, and what destroys one?
I'd like to see some more text explaining this.
3) MINOR: Feedback for recursive mitigation:
Section 3.2.3 says:
... To maximize
mitigation visibility to the DOTS client, however, the recursing
domain SHOULD provide recursed mitigation feedback in signals
reporting on mitigation status to the DOTS client. For example, the
recursing domain's mitigator should incorporate into mitigation
status messages available metrics such as dropped packet or byte
counts from the recursed mitigation.
This seems to imply that feedback from So to Cn is routed to Mn for
merging with Mn's feedback. That seems to violate the architecture. Can
the feedback from So be routed by Gn back to Cc?
Can this be clarified?
4) MINOR: Security of recursive mitigation:
The last paragraph of section 3.2.3 says:
Deployment of recursive signaling may result in traffic redirection,
examination and mitigation extending beyond the initial bilateral
relationship between DOTS client and DOTS server. As such, client
control over the network path of mitigated traffic may be reduced.
DOTS client operators should be aware of any privacy concerns, and
work with DOTS server operators employing recursive signaling to
ensure shared sensitive material is suitably protected.
This sounds like hand waving. Am I right in thinking this is talking
about incorporating the details of recursion in the service level agreement?
5) MINOR: Normative references:
I was surprised by the scarcity of normative references. I went looking
for MUSTs referencing RFCs and found three: RFC8612 (DOTS Requirements),
and RFCs 5389 and 7350 (STUN related). Please consider making these
normative references.
_______________________________________________
Gen-art mailing list
Gen-art@ietf.org
https://www.ietf.org/mailman/listinfo/gen-art
