Re: [Bier] Comments on draft-ietf-bier-pmmm-oam-04

[Suneesh <[e-mail]>]

Hi Greg,

Ok, agree that point.
So the marking always starts at the BFIR(Bit Forwarding Ingress Router),
which can be used for PMM at node, link, segment or end-to-end level.

Regards,
Suneesh

On Mon, Dec 10, 2018 at 11:14 PM Greg Mirsky <[e-mail]> wrote:

> Hi Suneesh,
> if the marking removed at the edge of the initial AltMark measurement
> domain, then adding the new measurement points would require communicating,
> coordinating more state than if the AltMark domain matches the BIER domain
> from the beginning. Would you agree?
>
> Regards,
> Greg
>
> On Mon, Dec 10, 2018 at 5:27 PM Suneesh <[e-mail]> wrote:
>
>> Hi Greg,
>>
>> Thanks, I'm a little confused about the following statement on clearing
>> the marking.
>> <snip>
>> It is expected that the marking values be set and cleared at the edge of
>> BIER domain.
>> </snip>
>>
>> Is it edge of BIER domain or edge of measurement domain(link or segment
>> or end to end).  Please let me know.
>>
>> Regards,
>> Suneesh
>>
>> On Mon, Dec 10, 2018 at 9:48 PM Greg Mirsky <[e-mail]>
>> wrote:
>>
>>> Hi Saneesh,
>>> thank you for your feedback. Please kindly consider the update to the
>>> draft reflected in the attached diff. Please let us know if the changes
>>> address your comments.
>>>
>>> Regards,
>>> Greg
>>>
>>> On Mon, Nov 26, 2018 at 4:31 PM Suneesh <[e-mail]> wrote:
>>>
>>>> Thanks Greg for the update, please find my comments inline below.
>>>>
>>>> Regards,
>>>> Suneesh
>>>>
>>>> On Thu, Nov 22, 2018 at 12:09 AM Greg Mirsky <[e-mail]>
>>>> wrote:
>>>>
>>>>> Now with the updated address to reach Giuseppe.
>>>>>
>>>>> On Wed, Nov 21, 2018 at 10:37 AM Greg Mirsky <[e-mail]>
>>>>> wrote:
>>>>>
>>>>>> Hi Suneesh,
>>>>>> thank you for the feedback and the detailed questions. Please find my
>>>>>> responses and notes in-line below tagged GIM>>.
>>>>>>
>>>>>> Regards,
>>>>>> Greg
>>>>>>
>>>>>> On Mon, Nov 19, 2018 at 9:24 AM Suneesh <[e-mail]> wrote:
>>>>>>
>>>>>>> Hi Greg,
>>>>>>>
>>>>>>> I have following comments on PMMM draft, please share your thoughts.
>>>>>>>
>>>>>>> Q1. Can you please share how the draft is viewed as a hybrid model?
>>>>>>>
>>>>>> GIM>> RFC 7799 provided the definition of active and passive
>>>>>> measurement methods. Hybrid methods are "in between" these two groups. Even
>>>>>> though the Alternate marking in BIER domain may use already preallocated
>>>>>> field, it does change the content of the header by applying the marking
>>>>>> values in the OAM field. Thus it is neither passive, nor active method but
>>>>>> "in between", i.e., hybrid. Would you agree?
>>>>>>
>>>>> Suneesh>>> Agreed
>>>>
>>>>>
>>>>>>> Ref: Section-3:
>>>>>>>
>>>>>>> <snip>
>>>>>>>    the marking method in BIER layer can be viewed as the example of
>>>>>>> the
>>>>>>>    hybrid performance measurement method
>>>>>>> </snip>
>>>>>>>
>>>>>>>
>>>>>>> Q2. Can you please define what is meant by sub-flows
>>>>>>>    a). Is the sub-flow set of flows on which marking method is
>>>>>>> applied OR
>>>>>>>    b). sub-flow-1 with say marking 0 and sub flow-2 with say marking
>>>>>>> 1 OR
>>>>>>>    c). Being a hybrid model, draft proposes to duplicate the
>>>>>>> multicast stream which is having marking and treated those as sub-flows?
>>>>>>>
>>>>>> GIM>> We use the term "sub-flow" as you've described in b).
>>>>>>
>>>>> Suneesh>>> Would be great if we can capture in the draft for more
>>>> clarity
>>>>
>>>>> Ref: Section-4: Theory of Operation
>>>>>>> <snip>
>>>>>>>    Using the marking method a BFR creates distinct sub-flows in the
>>>>>>>    particular multicast traffic over BIER layer
>>>>>>> </snip>
>>>>>>>
>>>>>>>
>>>>>>> Q3. Is there any recommended values for 'number of packets' or/and
>>>>>>> 'time duration' for alternate marking method
>>>>>>>     a). Just to know what is recommended to avoid say number of
>>>>>>> packets/time duration = 1
>>>>>>>
>>>>>> GIM>> You're right, 1 or even 2 would not be useful. 3 packets? May
>>>>>> be.
>>>>>>
>>>>>>>
>>>>>>> Q4. Lets say that the nodes is like A->B->C->D->F->G->H->I, the
>>>>>>> segment of interest is B->C->D for performance measurement
>>>>>>>   a). Does the alternate marking values will clear from node D
>>>>>>> onwards?
>>>>>>>   b). If not, what is recommended if we wish to measure between
>>>>>>> G->H->I
>>>>>>>
>>>>>> GIM>> Very good question. It is expected that the marking values be
>>>>>> cleared at the edge of BIER domain and thus an operator may enable
>>>>>> measurements on segment G-H-I at any time.
>>>>>>
>>>>> Suneesh>> Please consider adding it to the draft
>>>>
>>>>>
>>>>>>> Ref: Section-4: Theory of Operation
>>>>>>>
>>>>>>> <snip>
>>>>>>>   Any combination of markings, Loss and/or Delay, can be applied to
>>>>>>> a multicast flow by
>>>>>>>   any Bit Forwarding Router (BFR) at either ingress or egress point
>>>>>>> to
>>>>>>>    perform node, link, segment or end-to-end measurement to detect
>>>>>>>    performance degradation defect and localize it efficiently.
>>>>>>> </snip>
>>>>>>>
>>>>>>> Q5. Can we somewhere capture that 'proto' field of BIER header
>>>>>>> should not be "OAM request/reply", though we are using OAM bits in header.
>>>>>>>
>>>>>>> <snip>
>>>>>>>    The OAM field MUST be used only
>>>>>>>    for the performance measurement of data traffic in BIER layer.
>>>>>>> </snip>
>>>>>>>
>>>>>>>
>>>>>> GIM>> I think it would be too restrictive. One may want to measure
>>>>>> performance of BIER OAM.
>>>>>>
>>>>> Suneesh >>> I understood your point. Thanks.
>>>>
>>>>
>>>>> Regards,
>>>>>>> Suneesh
>>>>>>>
>>>>>>