[Teas] A review of draft-ietf-teas-enhanced-vpn

[Adrian Farrel <[e-mail]>]

Hi,

As the slicing framework is queued for working group last call, I thought it
would be helpful to do a review of this draft to get it ready for last call
as well.

As you might expect, I found a number of nits, and some small comments. My
general view is that this document is in pretty good shape.

Cheers,
Adrian

===

Throughout

You use "Layer-3", "layer-3", "Layer 3", and "layer 3" in this document.
Need to pick one.

---

Abstract

s/over/beyond/
s/traditional/existing/

---

1.

s/a connectivity services/a connectivity service/
s/IETF network slices/IETF Network Slices/
s/"IETF network slice"/"IETF Network Slice"/
s/ [RFC7926] and/ [RFC7926], and/
s/underlay and the overlay/overlay and the underlay/
d/traditional/    twice
s/enhanced data plane/data plane for enhanced VPNs/

---

2.

s/provides the/provides/
s/VTN has the/A VTN has the/

---

2. List of terms

Probably worth adding SLA, SLE, and SLO in this list with references to the
slicing framework.

VTN might be better to reference RFC 8453 rather than the YANG model.

---

3.1

s/This can be achieved/This could be achieved/

It is OK to say that per-VPN TE-LSPs are not widely deployed. But maybe also
say, "...the more common approach of aggregating multiple VPNs onto common
TE-LSPs results in shared bandwidth and so may reduce the assurance of
bandwidth to any one service."

s/provide these guarantees/provide a guaranteed upper bound to latency/
s/considered./considered when a guaranteed latency service is required./
s/attempts to deliver/attempts to deliver a copy of/
s/loss due to/loss in the event of/

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3.2

s/isolation./insolation within the underlay network./

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3.2.1

OLD
   resources, a significant
   economic advantage when compared to a dedicated, or a Time Division
   Multiplexing (TDM) network.
NEW
   resources: a significant
   economic advantage when compared to a dedicated or a Time Division
   Multiplexing (TDM) network.
END

---

3.2.1

   Clearly, there is no need to provide
   more isolation than is required by the applications, ...

Is "application" right? The service provider is unaware of the application.
Perhaps...

   Clearly, there is no need for a customer to request more isolation
   than their applications require, and no need for a service provider
   to provide more isolation than requested by their customer, ...

---

3.2.1

s/in most cases/in most cases when hard isolation is requested/

---

3.3

s/demanded by an/demanded of an/

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3.4

s/disruptive to that VPN,/disruptive to that VPN itself,/
s/Section 5.1,Section 5.2/Section 5.1, Section 5.3/

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3.4

Maybe the last two paragraphs would sit better as the 2nd and 3rd paragraphs
of the section.

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3.5

s/However, depends/However, depending/

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4.

s/and a corresponding VTN/and mapped to a corresponding VTN/

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4.1

s/resource partitioning,/resource partitioning of the physical network
infrastructure,/
s/and is associated/and each associated/
s/Thus VTN is/Thus the VTN is/
s/its customers/the service provider's customers/

---

4.4

s/even in future/even in the future/

---

5.1

s/which provide/which can provide/

---

5.1.1

s/fixed- bandwidth/fixed-bandwidth/

---

5.2.1

s/Virtual Transport Path (VTP)/ Virtual Transport Paths (VTPs)/

---

5.2.3

The section should indicate MPLS and IPv6 data plane are both supported.

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5.2.3

   An SR traffic engineered path operates with a granularity of a link.
   Hints about priority are provided using the Traffic Class (TC) or
   Differentiated Services Code Point (DSCP) field in the packet header.

I think the naming is wrong here. In both MPLS and IPv6 the field is called
the Traffic Class field.

---

5.4

s/requirements on connectivity/requirements for connectivity/

---

5.6

s/a SDN/an SDN/

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6.

The framework has change the name from NBI to "IETF Network Slice Service
Interface".

---

6.1

s/need to be created/need to be created to support the requested enhanced
VPNs/

---

6.4

s/by operator's policy/by the operator's policy/

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7.

Maybe give some clue about what is coming next. Such as
   The sections that follow describe some of
   the scalability concerns that need to be considered.

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7.2

s/traditional/established/

---

Perhaps sections 8 and 9 could be combined into a single section on
"Management Considerations"?

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11.

d/traditional/

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12.

Maybe add a final paragraph like...
   An enhanced VPN (even one with hard isolation requirements) does not
   provide any additional guarantees of privacy for customer traffic
   compared to regular VPNs: the traffic within the network may be
   intercepted and errors may lead to mis-delivery.  Users who wish to
   ensure the privacy of their traffic must take their own precautions
   including end-to-end encryption.

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16.2

I think [I-D.ietf-teas-actn-yang] is not used.