Subject: [Detnet] Suresh Krishnan's No Objection on draft-ietf-detnet-architecture-11: (with COMMENT)

From: Suresh Krishnan <[email-masked]>
Date: Thu, 21 Feb 2019 06:11:23 -0800

Suresh Krishnan has entered the following ballot position for
draft-ietf-detnet-architecture-11: No Objection

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COMMENT:
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* Section 3.2.1.1.

Given that we also know some of the downsides as well of large buffers, I think
a pointer to some background might be warranted here. I would recommend a basic
reference to something like

Bufferbloat: Dark Buffers in the Internet, Communications of the ACM, January
2012,

* Section 3.2.2.2.

It is not obvious to me how the POF cannot be the last operation at the
receiver. Can you clarify? Also, do intermediate nodes apply the POF? I can see
the need for them to do PRF and PEFs but I am not sure applying the POF at
intermediate nodes can necessarily help the low latency and low jitter goals.

   The order in which a DetNet node applies PEF, POF, and PRF to a
   DetNet flow is implementation specific.

* Section 3.2.3.

RFC7426 does not contain much specific information about explicit route setup.
Is there a particular section you want to point to. If not, I don't think this
reference is of much use. RFC8453 is listed twice.

* Section 3.3.1.

Not sure why this is a requirement but I do wish to note that there are no such
worst-case latency guarantees for best effort traffic (aka non-Detnet) in
current networks. Can you clarify?

   o  DetNet flows can be shaped or scheduled, in order to ensure that
      the highest-priority non-DetNet packet is also ensured a worst-
      case latency.

* Section 4.1.1.

This text "Peers with Duplicate elimination." seems to be completely out of
place under the "Packet sequencing" heading below Figure 2. Copy and paste
error?

* Section 4.3.2.

I found the expression "number of bit times" confusing. I have understood "bit
time" to mean the amount of time taken to emit a bit from a network interface.
Based on that definition, this expression does not make sense. Is there a
better reference/definition of what you mean?

* Section 4.5.

There might be some other recent IETF defined mechanisms that might be relevant
to mention here as well. e.g. RFC8289 (Codel), RFC8033 (PIE) etc.

* Section 4.7.2.

While IPv6 does offer a mechanism to add/remove a flow id (flow label) not sure
what kind of mapping you were thinking for IPv4. If this is not possible, I
think a note to that effect might be useful here.

* Sections 5 and 6

I also support Alissa and Benjamin's DISCUSSes (on privacy and security) and
would like to see them addressed.