Last Call Review of draft-ietf-spring-srv6-network-programming-17
review-ietf-spring-srv6-network-programming-17-opsdir-lc-romascanu-2020-08-20-2-00

Request Review of draft-ietf-spring-srv6-network-programming
Requested rev. no specific revision (document currently at 19)
Type Last Call Review
Team Ops Directorate (opsdir)
Deadline 2020-08-26
Requested 2020-08-12
Authors Clarence Filsfils, Pablo Camarillo, John Leddy, Daniel Voyer, Satoru Matsushima, Zhenbin Li
Draft last updated 2020-08-20
Completed reviews Opsdir Last Call review of -17 by Dan Romascanu (diff)
Tsvart Last Call review of -17 by Mirja K├╝hlewind (diff)
Secdir Last Call review of -17 by Brian Weis (diff)
Secdir Telechat review of -19 by Brian Weis
Intdir Telechat review of -18 by Brian Haberman (diff)
Assignment Reviewer Dan Romascanu
State Completed
Review review-ietf-spring-srv6-network-programming-17-opsdir-lc-romascanu-2020-08-20-2
Posted at https://mailarchive.ietf.org/arch/msg/ops-dir/e6Z4kYePx-SukJCOpaJPf4V-QO8
Reviewed rev. 17 (document currently at 19)
Review result Has Issues
Review completed: 2020-08-20

Review
review-ietf-spring-srv6-network-programming-17-opsdir-lc-romascanu-2020-08-20-2

This document together with the companion document [I-D.filsfils-spring-srv6-net-pgm-illustration] defines the SRv6 Network Programming concept and specifies the main segment routing behaviors to enable the creation of interoperable overlays with underlay optimization (Service Level Agreement).

The document is Ready.  There are a number of issues from an Operations and Management perspective that need further work, and it is assumed that they will be subject to work in the future. Some clarification on these issues would be however welcome before document approval. 

There are several references that are work-in-progress. For example basic concepts need to be understood from [I-D.filsfils-spring-srv6-net-pgm-illustration]. The control plane interaction is based on BGP-LS  [I-D.ietf-idr-bgpls-srv6-ext] or on BGP IP/VPN/EVPN [I-D.ietf-bess-srv6-services]. These documents are listed as Informative References probably in order to avoid a downref for this Standards Track document, but actually this document cannot be implemented or even understood without stable versions of the later. 

From the operators point of view I would like to draw the attention on Sections 6 and 8. 
- Section 6 (Operation) recommends the implementation of a implement a combined traffic counter (packets and bytes) per local SID entry. There is no indication how an operator would retrieve this information and if and how the values of these counters could be used for operational purposes. Adding such information would be useful.
- Section 8 (Control Plane) describes how the controllers can explicitly provision the SIDs and/or discover them as part of a service discovery function. Subsections describe the usage of IGP, BGP-LS, and BGP IP/VPN/EVPN for these purposes. Operators should be aware that one or more of these protocols also need to be supported in an SDN deployment.