[netconf] kw review of draft-wu-netconf-nmda-compatibility-01

Kent Watsen <kent@watsen.net> Mon, 25 March 2019 05:29 UTC

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Date: Mon, 25 Mar 2019 05:29:10 +0000
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Subject: [netconf] kw review of draft-wu-netconf-nmda-compatibility-01
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I started reading this document, but struggled with this sentence in the Introduction:

“NMDA Transition Guidelines in section 4.23.3 of [RFC8407] <snip/> doesn't provide guidelines on whether existing NETCONF protocol operations such as get/get-config/edit-config change semantics when they are exchanged between the non NMDA client and the NMDA aware  server.”

Correct, no statements are made (here or in RFC 8526), because no changes exist.  RFC 6241 is unchanged by RFC 8526. 

The draft also has this statement in the Problems section:

“When a server is upgraded to NMDA aware server and needs to support
both NMDA client and non-NMDA clients, there is no standards-based way for the server to know whether the client supports NMDA.”

True, but it doesn’t matter, as the server only cares if the client uses the RPC from RFC 6241 or RFC 8526.  

In order to maintain backwards compatibility, there are *no* changes to RFC 6241.   It is an implementation issue for the NMDA-aware server to maintain support for the non-NMDA aware RPCs.  

FWIW, the draft also has suggestions for clarifying NMDA behavior (e.g., with-defaults), which may be needed, but I didn’t dig into these suggestions as I want to first ensure my understanding of the problem statement. 

Kent // contributor