I have reviewed this document from a YANG model perspective only. The document contains very simple YANG model ietf-nat-sctp augmenting ietf-nat by a few values. The module compiles by tools with no error or warning and the only note I have is to the tag in the draft's text which misses filename for the module, it should look like this: file "ietf-nat-sctp@2019-11-18.yang"