Re: [Lsr] New Version Notification for draft-wang-lsr-isis-mfi-00.txt

[wangyali <[e-mail]>]

Hi Peter,

Thanks for your question. Please see inline [yali3].

-----Original Message-----
From: Peter Psenak [mailto:[e-mail]] 
Sent: Thursday, March 4, 2021 11:20 PM
To: wangyali <[e-mail]>; Gyan Mishra <[e-mail]>; Robert Raszuk <[e-mail]>
Cc: Huzhibo <[e-mail]>; Aijun Wang <[e-mail]>; Tony Li <[e-mail]>; lsr <[e-mail]>; Tianran Zhou <[e-mail]>
Subject: Re: [Lsr] New Version Notification for draft-wang-lsr-isis-mfi-00.txt

Hi Yali,

On 04/03/2021 14:45, wangyali wrote:
> Hi Peter,
> 
> Please see inline [Yali2]. Thanks a lot.
> 
> -----Original Message-----
> From: Peter Psenak [mailto:[e-mail]]
> Sent: Thursday, March 4, 2021 6:50 PM
> To: wangyali <[e-mail]>; Gyan Mishra 
> <[e-mail]>; Robert Raszuk <[e-mail]>
> Cc: Huzhibo <[e-mail]>; Aijun Wang 
> <[e-mail]>; Tony Li <[e-mail]>; lsr 
> <[e-mail]>; Tianran Zhou <[e-mail]>
> Subject: Re: [Lsr] New Version Notification for 
> draft-wang-lsr-isis-mfi-00.txt
> 
> Hi Yali,
> 
> On 04/03/2021 11:42, wangyali wrote:
>> Hi Peter,
>>
>> Please review follows tagged by [Yali].
>>
>>
>> -----Original Message-----
>> From: Peter Psenak [mailto:[e-mail]]
>> Sent: Wednesday, March 3, 2021 5:37 PM
>> To: wangyali <[e-mail]>; Gyan Mishra 
>> <[e-mail]>; Robert Raszuk <[e-mail]>
>> Cc: Huzhibo <[e-mail]>; Aijun Wang 
>> <[e-mail]>; Tony Li <[e-mail]>; lsr 
>> <[e-mail]>; Tianran Zhou <[e-mail]>
>> Subject: Re: [Lsr] New Version Notification for 
>> draft-wang-lsr-isis-mfi-00.txt
>>
>> Yali,
>>
>> On 03/03/2021 06:02, wangyali wrote:
>>> Hi Peter,
>>>
>>> Thanks for your comments. Yes. I am improving this sentence. Please review the following update.
>>>
>>> OLD: " And Level 1/Level 2 PSNP and Level 1/Level 2 CSNP containing information about LSPs that transmitted in a specific MFI are generated to synchronize the LSDB corresponding to the specific MFI."
>>>
>>> NEW: "And Level 1/Level 2 PSNP and Level 1/Level 2 CSNP containing information about LSPs that transmitted in a specific MFI are generated to synchronize the MFI-specific sub-LSDB. Each MFI-specific sub-LSDB is subdivided from a single LSDB."
>>
>> please specify sub-LSDB.
>> [Yali] Thanks for your comment. But to avoid introducing a new term, I change to use "MFI-specific LSDB" instead of " MFI-specific sub-LSDB ".  And we give the explanation that "Each MFI-specific LSDB is subdivided from a single LSDB."
> 
> I wonder what is the difference between "MFI-specific LSDB subdivided from a single LSDB" versus the "MFI-specific LSDB".
> [Yali2]: Actually I am trying to optimize and accurately describe the key point that multiple Update processes associated with each MFI operate on a common LSDB within the zero IS-IS instance, and each Update process is isolated from each other and does not affect each other.
> So we say "MFI-specific LSDB subdivided from a single LSDB", which may explicitly indicate each MFI-specific LSDB shares a common LSDB but each Update process associated with a MFI is isolated. However, from your previous question and suggestions,  "MFI-specific LSDB" looks like unclear and misleading. Any good idea on improving the expression are welcome.


it's not the name that is as important. It's the concept that looks questionable - how well can you isolate the update processing if the data are part of the same LSDB and whether such update process separation would prove to be useful at all. I don't know, so far I have not seen any evidence.
[yali3] This draft defines a new TLV, i.e. MFI-ID TLV,  which may be included in each Level 1/Level 2 IS-IS LSPs and SNPs. Hence, each Level 1/Level 2 LSPs and SNPs associated with each Update Process can be uniquely identified by MFI-ID. 
In this draft, each flooding instance has its own separated Update process, which isolates the impact of application information flooding on the IS-IS protocol operation. So each Level 1/Level 2 LSP associated with a specific MFI carries flooding information belonging to the specific MFI. And Level 1/Level 2 PSNP and Level 1/Level 2 CSNP containing information about LSPs that propagated in the specific MFI are generated to synchronize the MFI-specific LSDB.

thanks,
Peter




> 
> thanks,
> Peter
> 
>>
>> thanks,
>> Peter
>>
>>
>>>
>>> Best,
>>> Yali
>>>
>>> -----Original Message-----
>>> From: Peter Psenak [mailto:[e-mail]]
>>> Sent: Tuesday, March 2, 2021 5:12 PM
>>> To: wangyali <[e-mail]>; Gyan Mishra 
>>> <[e-mail]>; Robert Raszuk <[e-mail]>
>>> Cc: Huzhibo <[e-mail]>; Aijun Wang 
>>> <[e-mail]>; Tony Li <[e-mail]>; lsr 
>>> <[e-mail]>; Tianran Zhou <[e-mail]>
>>> Subject: Re: [Lsr] New Version Notification for 
>>> draft-wang-lsr-isis-mfi-00.txt
>>>
>>> Yali,
>>>
>>> On 01/03/2021 10:49, wangyali wrote:
>>>> Hi Peter,
>>>>
>>>> Many thanks for your feedback. First of all, I'm sorry for the confusion I had caused you from my previous misunderstanding.
>>>>
>>>> And I want to clarify that a single and common LSDB is shared by all MFIs.
>>>
>>> well, the draft says:
>>>
>>> "information about LSPs that transmitted in a
>>>      specific MFI are generated to synchronize the LSDB corresponding to
>>>      the specific MFI."
>>>
>>> If the above has changed, then please update the draft accordingly.
>>>
>>> thanks,
>>> Peter
>>>
>>>
>>>
>>>>
>>>> Best,
>>>> Yali
>>>>
>>>> -----Original Message-----
>>>> From: Peter Psenak [mailto:[e-mail]]
>>>> Sent: Sunday, February 28, 2021 8:23 PM
>>>> To: Gyan Mishra <[e-mail]>; Robert Raszuk 
>>>> <[e-mail]>
>>>> Cc: Huzhibo <[e-mail]>; Aijun Wang 
>>>> <[e-mail]>; Tony Li <[e-mail]>; lsr 
>>>> <[e-mail]>; Tianran Zhou <[e-mail]>; wangyali 
>>>> <[e-mail]>
>>>> Subject: Re: [Lsr] New Version Notification for 
>>>> draft-wang-lsr-isis-mfi-00.txt
>>>>
>>>> Gyan,
>>>>
>>>> On 26/02/2021 17:19, Gyan Mishra wrote:
>>>>>
>>>>> MFI seems more like flex algo with multiple sub topologies sharing 
>>>>> a common links in a  topology where RFC 8202 MI is separated at 
>>>>> the process level separate LSDB.  So completely different and of 
>>>>> course different goals and use cases for MI versus MFI.
>>>>
>>>> I would not use the fle-algo analogy - all flex-algos operate on top of a single LSDB, contrary to what is being proposed in MFI draft.
>>>>
>>>>>
>>>>>       MFI also seems to be a flood reduction mechanism by creating 
>>>>> multiple sub topology instances within a common LSDB.  There are a 
>>>>> number of flood reduction drafts and this seems to be another 
>>>>> method of achieving the same.
>>>>
>>>> MFI draft proposes to keep the separate LSDB per MFI, so the above analogy is not correct either.
>>>>
>>>> thanks,
>>>> Peter
>>>>
>>>>
>>>>>
>>>>> Gyan
>>>>>
>>>>> On Fri, Feb 26, 2021 at 7:10 AM Robert Raszuk <[e-mail] 
>>>>> <mailto:[e-mail]>> wrote:
>>>>>
>>>>>         Aijun,
>>>>>
>>>>>         How multi instance is implemented is at the discretion of a vendor.
>>>>>         It can be one process N threads or N processes. It can be both and
>>>>>         operator may choose.
>>>>>
>>>>>         MFI is just one process - by the spec - so it is inferior.
>>>>>
>>>>>         Cheers,
>>>>>         R.
>>>>>
>>>>>
>>>>>         On Fri, Feb 26, 2021 at 12:44 PM Aijun Wang <[e-mail]
>>>>>         <mailto:[e-mail]>> wrote:
>>>>>
>>>>>             Hi, Robert:
>>>>>
>>>>>             Separate into different protocol instances can accomplish the
>>>>>             similar task, but it has some deployment overhead.
>>>>>             MFIs within one instance can avoid such cumbersome work, and
>>>>>             doesn’t affect the basic routing calculation process.
>>>>>
>>>>>             Aijun Wang
>>>>>             China Telecom
>>>>>
>>>>>>             On Feb 26, 2021, at 19:00, Robert Raszuk <[e-mail]
>>>>>>             <mailto:[e-mail]>> wrote:
>>>>>>
>>>>>>             Hi Yali,
>>>>>>
>>>>>>                 If this was precise, then the existing multi-instance
>>>>>>                 mechanism would be sufficient.
>>>>>>                 [Yali]: MFI is a different solution we recommend to solve
>>>>>>                 this same and valuable issue.
>>>>>>
>>>>>>
>>>>>>             Well the way I understand this proposal MFI is much weaker
>>>>>>             solution in terms of required separation.
>>>>>>
>>>>>>             In contrast RFC8202 allows to separate ISIS instances at the
>>>>>>             process level, but here MFIs as defined must be handled by the
>>>>>>             same ISIS process
>>>>>>
>>>>>>                 This document defines an extension to
>>>>>>                 IS-IS to allow*one standard instance*  of
>>>>>>                 the protocol to support multiple update
>>>>>>                 process operations.
>>>>>>
>>>>>>             Thx,
>>>>>>             R.
>>>>>>
>>>>>>             _______________________________________________
>>>>>>             Lsr mailing list
>>>>>>             [e-mail] <mailto:[e-mail]>
>>>>>>             https://www.ietf.org/mailman/listinfo/lsr
>>>>>
>>>>>         _______________________________________________
>>>>>         Lsr mailing list
>>>>>         [e-mail] <mailto:[e-mail]>
>>>>>         https://www.ietf.org/mailman/listinfo/lsr
>>>>>
>>>>> --
>>>>>
>>>>> <http://www.verizon.com/>
>>>>>
>>>>> *Gyan Mishra*
>>>>>
>>>>> /Network Solutions A//rchitect /
>>>>>
>>>>> /M 301 502-1347
>>>>> 13101 Columbia Pike
>>>>> /Silver Spring, MD
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>
>>
>>
> 
> 
>