Early Review of draft-ietf-spring-srv6-yang-base-02
review-ietf-spring-srv6-yang-base-02-yangdoctors-early-lhotka-2026-05-20-00

This I-D defines a base data model for IPv6 segment routing (SRv6). It is
designed to be augmented by other SRv6 data models for specific routing
protocols. The base data model consists of two YANG modules:

- ietf-srv6-types defines identities, derived types and groupings

- ietf-srv6-base defines actual configuration and state data as well as two
notifications

**** General comments

- Identities defined in ietf-srv6-types correspond to the IANA registry "SRv6
Endpoint Behaviors". They should instead appear in an IANA-maintained YANG
module that mirrors this registry, see draft-ietf-netmod-iana-yang-guidance.

- Examples of instance data (configuration, state data and notification) would
be useful.

**** Specific comments

- Sec. 1 states: "YANG [RFC6020] is a modular language that represents data
structures in an XML tree format, [...]". Both modules in this I-D declare YANG
version 1.1, so the correct reference should be RFC 7950. Also XML is no more
the only possible data representation format, JSON and CBOR are comonly used.

- XPath function derived-from-or-self() is used 4 times in ietf-srv6-base. In
all cases, the identities used as the second parameter are defined in the
ietf-srv6-types module, so they have to carry the prefix, e.g.

  derived-from-or-self(../type, 'srv6-types:srv6-sid-fmt-uc-1')

- Both modules have to be reformatted to fit the 72-character limit [RFC 7994].
In most cases, the excessive line length is caused by description text starting
on the same line as the "description" keyword, with subsequent lines indented
accordingly. These description statements should be reformatted in the usual
style

  description
    "Description text ....";