Subject: [Nfvrg] draft-irtf-nfvrg-nfv-policy-arch-03 - even more comments and suggestions

From: Andrew Veitch <[email-masked]>
Date: Tue, 3 May 2016 20:45:40 +0000

A few more comments….

I think there is an error in Figure 1, in the Network Subsystem block. Based on the QoS context, I assume DHCP should be DSCP.
I also have a number of comments or questions on section 4, on Static vs. Dynamic vs. Autonomic Policies.
First, I think the first paragraph is a bit confusing.
The first reason is that it is a single very long sentence. It just makes it a bit hard to follow.  I have re-written it here, breaking it apart a bit, and I hope making it clearer as a result.
Policies can be defined based on a diverse set of constraints and sources.  For example, an operator may base its policy for energy cost reduction on time-varying energy rates imposed by its utility company.  (I removed the “for a given region” as it seemed unnecessary.)   That operator’s "green" policies may be based on its green operational requirements.  While these policies may result in decreased energy consumption, they may also drive increased energy costs.
At least, that is the meaning I gleaned from the original text.
Another reason for my confusion regarding the first paragraph is because, while I see how it relates to the example later in the section, it should not be the lead paragraph of the section. It includes no information related to the title.  There is no reason to have this text separate from the rest of the example later on.

Second, I find the concepts of the Static vs. Dynamic vs. Autonomic policies a bit confusing.
The second paragraph leads with “While ‘static’ policies…” without defining what they are.  There should be a definition provided, as it is a new concept.
I believe the section is differentiating policies that have fixed or immutable constraint values, vs. policies that have constraint values that are variable, where the values may change based upon environmental conditions.   It calls a policy with fixed or constant constraints a “static policy” and one with variable constraints a “dynamic policy.”  [I may have this wrong; it is what makes sense to me.]
The first example references a use case where, due to a sporting or concert event, the scaling of users must grow.  But is it fuzzy in describing the policy.
It also says a “dynamic policy can be imposed to temporarily override a static policy”, but it does not describe how this would work.  For me, there could be a third policy that considers some of the environmental values, e.g. it is triggered when it learns of the sporting event, and it updates the “max users” constraint of the other policy.  Thought this sort of behavior could be set in more than one way.
For the final example that relates to the first paragraph, this text could be all in this one space.
As for autonomic policies vs. the other types,  it is not clear how it differs from a dynamic policy.  A better description is needed.

Third, my final comment is that I am not sure why this section is included here.  It interrupts the flow of the document.  Section 5 should follow section 3.  If these concepts are important for topics described later, then they should be introduced there.  Last, if these concepts are developed in more detail in another document, then it would be good to have that document included as a reference.

Thanks

Andy

________________________________
The information transmitted herein is intended only for the person or entity to which it is addressed and may contain confidential, proprietary and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.