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.