Futurewei Technologies LabN Consulting, L.L.C. Cisco Systems Nvidia This document defines two YANG data modules. The first is the initial version of the IANA-maintained YANG module for Maximum Segment Identifier (SID) Depths (MSDs) Types, which includes identities for both the MPLS and SRv6 data planes. The second augments the IETF MPLS YANG model to provide support for MPLS MSDs as defined in RFC 8476 and RFC 8491.