Re: [sfc] is current SFC architecture supporting different types of SFC header formats?

["Joel M. Halpern" <[e-mail]>]

Not quite "any".  The working group made some choices about behavior as 
part of the process.  If the architecture did not make any choices, then 
there would be no point in having the architecture.  We did not however 
mandate the specific encodings, and there are a fair range of possible 
realizations.  Neither I nor Carlos attempted to review all the existing 
proposals to determine if as they exist they fit the architecture or if 
they could be adjusted to fit.  That is up to the proposers.

For example, I suppose that one could write a solution proposal that 
required co-location of certain components.  But that would then be an 
important property of the proposal to be discussed by the WG.

Yours,
Joel

On 12/4/14, 10:47 AM, Georgios Karagiannis wrote:
> Hi Joel,
>
> Thanks for your email! I understand that the SFC architecture draft
> does not specify how the required information is encoded in the
> header.
>
> Therefore, I am also assuming that (1) the SFC Encapsulation function
> described in section 4.1, (2) the Classification function described
> in section 4.7 and (3) the Shared Metadata function described in
> Section 4.9, are described in such a way that any SFC encapsulation
> technique should be supported.
>
> Best regards, Georgios
>
>
>
>> -----Original Message----- From: Joel M. Halpern
>> [mailto:[e-mail]] Sent: Thursday, December 04, 2014 4:32
>> PM To: Georgios Karagiannis Cc: [e-mail] Subject: Re: [sfc] is
>> current SFC architecture supporting different types of SFC header
>> formats?
>>
>> To reinforce Carlos' point, the architecture document is quite
>> careful not to specify how the required information is encoded in
>> the header. It is up to the WG to select a single such
>> encapsulation that meets the requirements from among the multiple
>> choices being presented in individual drafts.
>>
>> Yours, Joel
>>
>> On 12/4/14, 10:18 AM, Carlos Pignataro (cpignata) wrote:
>>> Hi Georgios,
>>>
>>> Please see inline.
>>>
>>>> On Dec 4, 2014, at 9:40 AM, Georgios Karagiannis
>> <[e-mail]> wrote:
>>>>
>>>> Hi Carlos,
>>>>
>>>> Please note that I do not mean to use different SFC
>>>> encapsulations
>> simultaneously.
>>>>
>>>
>>> Thanks for the clarification.
>>>
>>>> From what I understood from IETF'91 meeting discussions, the
>>>> Generic SFC
>> encapsulation technique has not yet been selected by the SFC WG.
>>>>
>>>> I think that this means that the SFC architecture draft cannot
>>>> be in favor for one specific SFC encapsulation technique and at
>>>> the same time
>> excluding other techniques.
>>>>
>>>
>>> Yes. Again, the SFC architecture document does not concern itself
>>> or take
>> any position on any specifics for any encapsulation format. It does
>> specify the functions that the SFC encapsulation need to fulfill.
>>>
>>>> My question is:
>>>>
>>>> Can the following two SFC encapsulation techniques be supported
>>>> by the
>> functions described in the SFC architecture draft?:
>>>>
>>>> o) Single Marking Code Point, like format, see section 5.1 on
>>>> boucadair
>> draft, see below.
>>>>
>>>> o) Explicit Route List, like format, see section 5.3 on
>>>> boucadair draft,
>> see below.
>>>>
>>>
>>> I see — this is a question for
>>> draft-boucadair-sfc-design-analysis and not
>> for draft-ietf-sfc-architecture. Meaning, it would be up to the
>> proposed encapsulation to show how they realize the functions of
>> the architecture.
>>>
>>> That said, I do not see an “SF Map Index” in the architecture
>>> document, for
>> example.
>>>
>>> Thanks,
>>>
>>> Carlos.
>>>
>>>> http://www.ietf.org/id/draft-boucadair-sfc-design-analysis-03.txt
>>>>
>>>>
>>>>
Best regards,
>>>> Georgios
>>>>
>>>>
>>>>
>>>>
>>>>> -----Original Message----- From: Carlos Pignataro (cpignata)
>>>>> [mailto:[e-mail]] Sent: Thursday, December 04, 2014
>>>>> 3:02 PM To: Georgios Karagiannis Cc: [e-mail] Subject:
>>>>> Re: [sfc] is current SFC architecture supporting different
>>>>> types of SFC header formats?
>>>>>
>>>>> Hi, Georgios,
>>>>>
>>>>> Do you mean different SFC Encapsulations simultaneously? The
>>>>> SFC charter says:
>>>>>
>>>>> <snip> 3. Generic SFC Encapsulation: This document will
>>>>> describe a single service-level data plane encapsulation
>>>>> format that:
>>>>>
>>>>> </snip>
>>>>>
>>>>> Because interoperability is the goal.
>>>>>
>>>>> Looking at that section, the terminology does not seem to
>>>>> align to the arch and problem-statement documents. Also, that
>>>>> section seems to describe a pseudo-format, not a format. The
>>>>> architecture describes the functions in Section 4.1 and other
>>>>> places.
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Carlos.
>>>>>
>>>>> On 12/4/14, 8:55 AM, "Georgios Karagiannis"
>>>>> <[e-mail]> wrote:
>>>>>
>>>>>> Hi Carlos,
>>>>>>
>>>>>> Thanks for your answer!
>>>>>>
>>>>>> Does this mean that the SFC architecture is allowing the
>>>>>> use of different Service Function Chaining Header (SFC
>>>>>> encapsulation) formats?
>>>>>>
>>>>>> I am referring to the different SFC encapsulation formats
>>>>>> that are discussed in section 5 of the following ID:
>>>>>> http://www.ietf.org/id/draft-boucadair-sfc-design-analysis-03.txt
>>>>>>
>>>>>>
>>>>>>
Best regards,
>>>>>> Georgios
>>>>>>
>>>>>>
>>>>>>> -----Original Message----- From: Carlos Pignataro
>>>>>>> (cpignata) [mailto:[e-mail]] Sent: Thursday,
>>>>>>> December 04, 2014 2:46 PM To: Georgios Karagiannis Cc:
>>>>>>> [e-mail] Subject: Re: [sfc] is current SFC
>>>>>>> architecture supporting different types of  SFC header
>>>>>>> formats?
>>>>>>>
>>>>>>> Hi, Georgios,
>>>>>>>
>>>>>>> The SFC architecture document concerns itself with the
>>>>>>> functions and not the  format.
>>>>>>>
>>>>>>> Thanks,
>>>>>>>
>>>>>>> Carlos.
>>>>>>>
>>>>>>>> On Dec 4, 2014, at 5:17 AM, Georgios Karagiannis
>>>>>>> <[e-mail]> wrote:
>>>>>>>>
>>>>>>>> Hi all,
>>>>>>>>
>>>>>>>> Please note that I was reviewing the SFC architecture
>>>>>>>> draft, see
>>>>>>> below, and I have a question:
>>>>>>>> http://www.ietf.org/id/draft-ietf-sfc-architecture-02.txt
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
Can you please let me know if the current version of the SFC
>>>>>>>> architecture allows the use of different Service
>>>>>>>> Function Chaining
>>>>>>> Header formats?
>>>>>>>>
>>>>>>>> These formats and their analysis can be found in
>>>>>>>> Section 5 of the
>>>>>>> following draft:
>>>>>>>>
>>>>>>>> http://www.ietf.org/id/draft-boucadair-sfc-design-analysis-03.txt
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
If that is not the case, please elaborate why.
>>>>>>>>
>>>>>>>> Best regards, Georgios
>>>>>>>>
>>>>>>>>
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>>>>>>>> https://www.ietf.org/mailman/listinfo/sfc
>>>>>>
>>>>
>>>
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