[Gen-art] Gen-ART review of draft-ietf-tsvwg-vpn-signaled-preemption-01

["Sharon Chisholm" <[e-mail]>]

	I am the the assigned General Area Review Team (Gen-ART)
reviewer for this draft (for background on Gen-ART, please see
http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html). 

	Please resolve these comments along with any other Last Call
comments you may receive. 

Document: 
--------

            QoS Signaling in a Nested Virtual Private Network
      <draft-ietf-tsvwg-vpn-signaled-preemption-01.txt>

Summary:
-------

	This draft is not quite ready for publication. 

Comments: 
--------- 

As this was a -00 version of the document (then published a few days ago
with minor changes as -01) I was curious as to how much review it
received from the working group. I reviewed the mailing list and only
saw one reply to working group last call on the document to make some
minor updates. It might be worthwhile to solicit the working group for
further review.

I expect that once some of these scope and organization issues are
addressed, the document will be a bit easier to review to find more
specific problems.

1. The document doesn't seem to agree on its purpose. In the abstract it
claims
"Some networks require communication between an interior and exterior
   portion of a VPN, but have sensitivities about what information is
   communicated across the boundary.  This note seeks to outline the
   issues and the nature of the proposed solutions."
But later on the document claims "The key question this document
explores is "how do reservations, and
   preemption of reservations, work in such an environment?", where such
an environment is nested VPNs. The document does seem to talk about both
and they seem related, but still this needs to be clarified.

2. The abstract says 'This note seeks to outline the issues and the
nature of the proposed solutions.', it would be good to refer to what
the specific solution are.

3. Section 1 is titled 'QoS in a VPN domain', but is actually a mishmash
of topics. It contains a reiteration of the purpose of the document with
respect to interior/exterior, tutorial on a number of topics, and some
clarification of term usage specific to this document. The title of the
section seems a bit off and the information within the section would be
better organized into the sections I mentioned or some other form to
reduce the feeling of 'here is some information' and 'here is some more
information' that this document has on occasion. 

4. Figure 2 is barely a figure and doesn't really demonstrate
communication between the three entities listed.

5. In section 1.1, titled 'Nested VPNs', we get three quarters of the
way through, in the paragraph just before figure 3, before we finally
start talking about nesting VPNs.

6. Figure 5 is very ambitious for ASCII art and I don't find it terribly
readable. This figure is then referenced through very long examples
walking through its H5 and R4 type labels. I wonder if this is a simpler
way to convey the same information?

7. Is DSCP corollary a well-known term? I googled and didn't find it
used. I also didn't see it defined in the document.

8. In section 2.1, second set of bullets it says "The Preemption
Priority of a tunnel reservation is identical to that of the individual
reservations it aggregates.", which implies that only reservations of
the same priority level can be put into an association. Is that correct?


9. In section 5, the fourth paragraph does not seem to be discussing a
security consideration.

10. Section 3 claims that it 'details the data flows within a VPN
Router, in the context of sessions as described in Section 2.', which
isn't that helpful. If we mean some of the nested VPNs discussed, we
should clearly say this rather then using a cryptic cross references. 

Nits
----

1. In section 1, first sentence, it says 'guarantee secure transmission
of IP traffic for across public LANs or WANs'. Delete the 'for'

2. Figure 1 is not readable because there is not sufficient space
between it and the preceding text.

3. Section 1.3, second paragraph says "Preemption of a reservation is
specified in the context,
   in [RFC3181]", which perhaps should read 'this context'.

4. In section 2.1, first sentence it says 'A reservation in a nest VPN'.
I believe that should be 'nested'.

5. In section 2.1, just before the bullets it says 'If the VPN Tunnel is
an IPSec Security Association between the VPN Routers and the IP packet
is entirely contained within ', which doesn't really parse.

6. In section 3.1.1., it says 'RESV Confirm:  This indicates that a RESV
message received as data
      and forwarded into the enclave, and is now being confirmed.',
which doesn't parse.

7. Section 3.2.1 first paragraph talks about 'th cipher', which should
be 'the cipher'.

8. Section 5, second paragraph says "One of the reasons cited for the
nesting of VPN routes in Section 1.1 are the different levels ", when
that should be 'is the different levels'. 
  

_______________________________________________
Gen-art mailing list
[e-mail]
https://www1.ietf.org/mailman/listinfo/gen-art