Re: [Int-dir] Intdir telechat review of draft-ietf-sfc-oam-framework-13

["Nagendra Kumar Nainar (naikumar)" <[e-mail]>]

Hi Carlos,

Thank you for the review and sharing the comments. Please see inline for the responses:

On 5/4/20, 8:30 AM, "Carlos Bernardos via Datatracker" <[e-mail]> wrote:

    Reviewer: Carlos Bernardos
    Review result: Ready with Nits
    
    Thanks a lot for this document. I liked reading it.
    
    I have a first generic comment, minor but that I still wanted to make. Section
    2 is about SFC Layering Model, which to me seems like an introduction, but not
    really specifically related to the core topic of the draft. Do we need that
    section in this draft? Maybe it can be condensed and included as a first part
    of section 3.
    
<Nagendra> Section 2 splits the SFC into layers that helps associate different SFC OAM components and its dependency on different layers. For ease of reading, I think we will leave it in this section.

    The document has a big component of requirements and gap analysis, which brings
    one question: should the document use normative RFC 2199 language when
    expressing the requirements? In Section 3.2.1 t is used, for example, but not
    in other parts. I think some work is needed to make this consistent.
   
<Nagendra> I hope you are referring to RFC2119 (BCP 14). We got similar comments from other reviewers and agreed to remove the section and avoid using any normative statements.

    I think that the following sentence needs to be reworded: "In order to apply
    such OAM functions at the service layer, they need to be enhanced to operate a
    single SF/SFF to multiple SFs/SFFs in an SFC and also in multiple SFCs."
    
<Nagendra>Ok. We modified it as below. Hope that clarifies:

OLD:
 
In order to apply
   such OAM functions at the service layer, they need to be enhanced to
   operate a single SF/SFF to multiple SFs/SFFs in an SFC and also in
   multiple SFCs.
   
NEW:
In order to apply
   such OAM functions at the service layer, they need to be enhanced to
   apply the OAM function on a single SF/SFF or multiple SFs/SFFs 
   spanning across one or more SFCs.

    I think the behaviour of SFC-aware nodes that do not support a given OAM
    operation should be better explained. For example, the sentence "When an SF
    supports OAM functionality, it is desirable to process the packet and provide
    an appropriate response to allow end-to-end verification." might be to vague.
    
<Nagendra> This is explained in the previous sentence as below:

" Upon receiving an OAM packet, SFC-aware SFs may choose to discard the
   packet if it does not support OAM functionality or if the local
   policy prevents them from processing the OAM packet."


    Table 4 has a small formatting issue in the Classifier row.
    
<Nagendra> Thank you. Fixed it and will be reflected in the new revision. 

    I think some in-band vs out-band OAM discussion would be interesting to add to
    the document.
    
   <Nagendra> While the whole document primarily focused on out-band, section 6.4 already talks about the applicability of In-band OAM tool to perform the OAM functions.
    
Once again, thanks a lot for the great comments.

Thanks,
Nagendra