Re: [Netconf] New Version Notification for draft-mahesh-netconf-binary-encoding-00.txt

[Mahesh Jethanandani <[e-mail]>]

Robert,

Thanks for your review of the document. Here are some initial responses, and we can discuss this further in London also.

> On Feb 23, 2018, at 4:08 AM, Robert Wilton <[e-mail]> wrote:
> 
> Hi Mahesh,
> 
> Some quick thoughts/comments on this draft:
> 
> 1) I think that it is good for NETCONF to support other encodings, particularly CBOR, and possibly JSON as well.  I particularly the like the CBOR+SID encoding that seems to be compact but not hard to support.
> 
Agree. 
> 2) I think that it would be good if RESTCONF could also support CBOR as well.  I'm not sure whether that could be covered by this draft of something else.
> 
Are you looking for a similar new capability URI for restconf to be added?
> 3) There needs to be a well defined registry of encodings, perhaps as identities.
> 
Ok. We need to decide where these identities can be defined. Currently, there is no YANG model defined in the draft.
> 4) CBOR supports using SIDs or strings for identifiers, so there would need to be a way of choosing between these.  Perhaps these would be listed as two different encodings.
> 
Yes.
> 5) Versioning might want to be considered, e.g. if there was an updated version of CBOR how would that be reported.
> 
How does CBOR report its version today? Or do they?
> 6) If CBOR is being used, and in which case, SIDs is probably the way to go, then there might need to be some consideration about how the client learns the SIDs, this may be covered by some of the CORE WG drafts, or might require new NETCONF/RESTCONF RPCs.
> 
I need to be educated here. We can discuss this further in London.
> 7) There is no encoding of metadata in CBOR, it might be useful if that was also considered, probably that would end up being a separate draft.
> 7b) Related to 7, how would the <edit-config> operations (merge, create, remove,  etc) be encoded.
> 7c) Would errors also be reported using a binary encoding, or would they stay in XML?
> 
Juergen had a similar question. After discussing with him, we will clarify in the next version of the document that the encoding will be for everything above the Messages layer per Figure 1 of RFC 6241. So the answer to 7c is that it will stay in XML. 

For 7b, and example conversion of a XML to JSON encoding would look like this:

In XML:

<rpc message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-config>
  <source>
    <running/>
  </source>
  <filter type="subtree">
        <interface-configurations xmlns="http://cisco.com/ns/yang/Cisco-IOS-XR-ifmgr-cfg">
     <interface-configuration>
      <active>act</active>
      <interface-name>GigabitEthernet0/0/0/0</interface-name>
     </interface-configuration>
    </interface-configurations>
  </filter>
</get-config>
</rpc> 

After switching to JSON encoding the same request would look something like (just noticed that type=“subtree” got dropped)

<rpc message-id="103" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
{
  "ietf-netconf:get-config": {
    "source": {
      "running": null
   },
    "filter": {
      "interface-configurations": {
        “xmlns":"http://cisco.com/ns/yang/Cisco-IOS-XR-ifmgr-cfg <http://cisco.com/ns/yang/Cisco-IOS-XR-ifmgr-cfg>",
        "interface-configuration": {
          "active": "act",
          "interface-name": "GigabitEthernet0/0/0/0"
        }
      }
    }
  }
}
</rpc>


> 8) Does there need to be any comment/considerations regarding YANG push and friends.
> 
Yes, there are considerations for YANG push and friends drafts. Eric tells me that there is an ability in subscribed notifications to change the encoding mid-stream.
> But in general, I'm supportive of IETF allowing binary encodings to be used in NETCONF/RESTCONF for devices that want to use them.  They seem to be particularly relevant to streaming telemetry related applications.
> 
Agree.
> Thanks,
> Rob
> 
> On 22/02/2018 02:29, Mahesh Jethanandani wrote:
>> This short draft proposes a mechanism for NETCONF clients and servers to negotiate an alternate form of encoding, e.g. binary encoding.
>> 
>> Cheers.
>> 
>>> Begin forwarded message:
>>> 
>>> From: [e-mail] <mailto:[e-mail]>
>>> Subject: New Version Notification for draft-mahesh-netconf-binary-encoding-00.txt
>>> Date: February 21, 2018 at 6:18:45 PM PST
>>> To: "Jason Lam" <[e-mail] <mailto:[e-mail]>>, "Alfred Leung" <[e-mail] <mailto:[e-mail]>>, "Mahesh Jethanandani" <[e-mail] <mailto:[e-mail]>>
>>> 
>>> 
>>> A new version of I-D, draft-mahesh-netconf-binary-encoding-00.txt
>>> has been successfully submitted by Mahesh Jethanandani and posted to the
>>> IETF repository.
>>> 
>>> Name:		draft-mahesh-netconf-binary-encoding
>>> Revision:	00
>>> Title:		Binary Encoding for NETCONF
>>> Document date:	2018-02-23
>>> Group:		Individual Submission
>>> Pages:		6
>>> URL:            https://www.ietf.org/internet-drafts/draft-mahesh-netconf-binary-encoding-00.txt <https://www.ietf.org/internet-drafts/draft-mahesh-netconf-binary-encoding-00.txt>
>>> Status:         https://datatracker.ietf.org/doc/draft-mahesh-netconf-binary-encoding/ <https://datatracker.ietf.org/doc/draft-mahesh-netconf-binary-encoding/>
>>> Htmlized:       https://tools.ietf.org/html/draft-mahesh-netconf-binary-encoding-00 <https://tools.ietf.org/html/draft-mahesh-netconf-binary-encoding-00>
>>> Htmlized:       https://datatracker.ietf.org/doc/html/draft-mahesh-netconf-binary-encoding-00 <https://datatracker.ietf.org/doc/html/draft-mahesh-netconf-binary-encoding-00>
>>> 
>>> 
>>> Abstract:
>>>   This document describes a method by which a NETCONF [RFC6241] client
>>>   and server can negotiate an alternate form of encoding.
>>> 
>>>   This document updates RFC 6241.
>>> 
>>> 
>>> 
>>> 
>>> Please note that it may take a couple of minutes from the time of submission
>>> until the htmlized version and diff are available at tools.ietf.org <http://tools.ietf.org/>.
>>> 
>>> The IETF Secretariat
>>> 
>> 
>> Mahesh Jethanandani
>> [e-mail] <mailto:[e-mail]>
>> 
>> 
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> 

Mahesh Jethanandani
[e-mail]