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

Peter Psenak <ppsenak@cisco.com> Thu, 04 March 2021 15:20 UTC

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To: wangyali <wangyali11@huawei.com>, Gyan Mishra <hayabusagsm@gmail.com>, Robert Raszuk <robert@raszuk.net>
Cc: Huzhibo <huzhibo@huawei.com>, Aijun Wang <wangaj3@chinatelecom.cn>, Tony Li <tony.li@tony.li>, lsr <lsr@ietf.org>, Tianran Zhou <zhoutianran@huawei.com>
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From: Peter Psenak <ppsenak@cisco.com>
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Date: Thu, 4 Mar 2021 16:20:12 +0100
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Subject: Re: [Lsr] New Version Notification for draft-wang-lsr-isis-mfi-00.txt
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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:ppsenak@cisco.com]
> Sent: Thursday, March 4, 2021 6:50 PM
> To: wangyali <wangyali11@huawei.com>om>; Gyan Mishra <hayabusagsm@gmail.com>om>; Robert Raszuk <robert@raszuk.net>
> Cc: Huzhibo <huzhibo@huawei.com>om>; Aijun Wang <wangaj3@chinatelecom.cn>cn>; Tony Li <tony.li@tony.li>li>; lsr <lsr@ietf.org>rg>; Tianran Zhou <zhoutianran@huawei.com>
> 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:ppsenak@cisco.com]
>> Sent: Wednesday, March 3, 2021 5:37 PM
>> To: wangyali <wangyali11@huawei.com>om>; Gyan Mishra
>> <hayabusagsm@gmail.com>om>; Robert Raszuk <robert@raszuk.net>
>> Cc: Huzhibo <huzhibo@huawei.com>om>; Aijun Wang
>> <wangaj3@chinatelecom.cn>cn>; Tony Li <tony.li@tony.li>li>; lsr
>> <lsr@ietf.org>rg>; Tianran Zhou <zhoutianran@huawei.com>
>> 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.

thanks,
Peter




> 
> thanks,
> Peter
> 
>>
>> thanks,
>> Peter
>>
>>
>>>
>>> Best,
>>> Yali
>>>
>>> -----Original Message-----
>>> From: Peter Psenak [mailto:ppsenak@cisco.com]
>>> Sent: Tuesday, March 2, 2021 5:12 PM
>>> To: wangyali <wangyali11@huawei.com>om>; Gyan Mishra
>>> <hayabusagsm@gmail.com>om>; Robert Raszuk <robert@raszuk.net>
>>> Cc: Huzhibo <huzhibo@huawei.com>om>; Aijun Wang
>>> <wangaj3@chinatelecom.cn>cn>; Tony Li <tony.li@tony.li>li>; lsr
>>> <lsr@ietf.org>rg>; Tianran Zhou <zhoutianran@huawei.com>
>>> 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:ppsenak@cisco.com]
>>>> Sent: Sunday, February 28, 2021 8:23 PM
>>>> To: Gyan Mishra <hayabusagsm@gmail.com>om>; Robert Raszuk
>>>> <robert@raszuk.net>
>>>> Cc: Huzhibo <huzhibo@huawei.com>om>; Aijun Wang
>>>> <wangaj3@chinatelecom.cn>cn>; Tony Li <tony.li@tony.li>li>; lsr
>>>> <lsr@ietf.org>rg>; Tianran Zhou <zhoutianran@huawei.com>om>; wangyali
>>>> <wangyali11@huawei.com>
>>>> 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 <robert@raszuk.net
>>>>> <mailto:robert@raszuk.net>> 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 <wangaj3@chinatelecom.cn
>>>>>         <mailto:wangaj3@chinatelecom.cn>> 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 <robert@raszuk.net
>>>>>>             <mailto:robert@raszuk.net>> 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
>>>>>>             Lsr@ietf.org <mailto:Lsr@ietf.org>
>>>>>>             https://www.ietf.org/mailman/listinfo/lsr
>>>>>
>>>>>         _______________________________________________
>>>>>         Lsr mailing list
>>>>>         Lsr@ietf.org <mailto:Lsr@ietf.org>
>>>>>         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
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>
>>
>>
> 
> 
>