# OPSDIR review of draft-ietf-teas-enhanced-vpn-18

I have reviewed this document as part of the Operational directorate's ongoing effort to review all IETF documents being processed by the IESG.  These comments were written with the intent of improving the operational aspects of the IETF drafts. Comments that are not addressed in the last call may be included in AD reviews during the IESG review.  Document editors and WG chairs should treat these comments just like any other last-call comments.

The document describes the NRP-based Enhanced VPNs framework. The document is almost ready for publication. Note that I had reviewed an earlier version during WGLC.

The document includes manageability considerations and Operational considerations sections that provide useful hints. Thanks for including these explicit sections. Some comments: 

- Section 8.1, is there any NRP-specific OAM text that should be explicitly listed?

- Section 8.2, I was hoping for some explicit text on the role of telemetry here as as well some high-level consideration even if the bulk of the mechanism is out of scope

- In section 10, you should reference back to section 5.6 here. Further are there any lifecycle concerns that should be highlighted that are specific to enhanced VPN? 

- I suggest moving current section 9 (Enhanced Resiliency) above section 8 (Manageability Considerations) to keep Manageability Considerations and Operational Considerations back to back. 

## Minor

- "...enhancements in some network layers and network planes."; 'Network planes' is unclear, I suggest adding "(data plane, control plane, and management plane)" alongside if that is what the authors mean...

- In section 2, NRP is listed twice in the initial relationship list as well as in the abbreviation list. 

- Section 4, Should OAM and telemetry be listed under the management plane?

- Section 5.2.3, should there be a reference to draft-ietf-spring-resource-aware-segments?

- Change reference to RFC 7752 to RFC 9552

- Section 7.3, the sentence "The centralized approach of SDN requires state to be stored in the network, but does not have the overhead of also requiring control plane state to be maintained" gives an impression that there is no control plane state if SDN is used which is not true. Further "...with the need for a control plane to maintain communication with all neighbors" is also unclear, which communication channel?
   
## Nits

- Expand NRP in the title and abstract. 

- Expand on first use - PE, 

- s/technologies and adds characteristics/technologies and add characteristics/

- s/but in addition they also/but in addition, they also/

- I suggest rephrasing "This is not a closed list." to "This list is not exhaustive."

- s/the general framework, the components, and interfaces/the general framework, components, and interfaces/

- s/service is deployment specific./service is deployment-specific./

- s/one or more NRP-based enhanced VPN/one or more NRP-based enhanced VPNs/

- s/not in scope for this document./not in the scope of this document./

- s/queues size, and discard policy/queue sizes, and discard policies/

- s/augumented/augmented/

- s/through different enhanced VPN./through different enhanced VPNs./

- s/a spectrum of service guarantees need to be/a spectrum of service guarantees needs to be/

- s/some service may have/some services may have/

- s/latency in network layer/latency in the network layer/

- s/requirements on separating/requirements for separating/

- s/expectations on traffic isolation./expectations of traffic isolation./

- s/provide the traffic isolation/provide traffic isolation/

- s/In some domains the network/In some domains, the network/

- s/IP based/IP-based/

- s/a link level technology/a link-level technology/

- s/DiffServ based queuing systems/DiffServ-based queuing systems/

- s/time sensitive/time-sensitive/

- s/such group of services./such a group of services./

- s/resource reserved paths/resource-reserved paths/

- s/performance related parameters/performance-related parameters/

- s/SDN based/SDN-based/

- s/And on the network nodes and links/On the network nodes and links/

- s/instructed to allocated the/instructed to allocate the/

- s/NRP specific/NRP-specific/

- s/of an network slice service/of a network slice service/

- s/together provide a network slice service./together provides a network slice service./

- s/based either the traffic-engineered paths/based on either the traffic-engineered paths/

- s/performance guaranteed services/performance-guaranteed services/

- s/NRP specific segments/NRP-specific segments/

- s/resource allocated path/resource-allocated path/

- s/performance sensitive application/performance-sensitive application/

Thanks,
Dhruv