Hi Yali,
On 05/03/2021 15:31, wangyali wrote:
Hi Peter,
Thanks for your question. Please see inline [yali3].
-----Original Message-----
From: Peter Psenak [mailto:[email protected]]
Sent: Thursday, March 4, 2021 11:20 PM
To: wangyali <[email protected]>; Gyan Mishra <[email protected]>; Robert
Raszuk <[email protected]>
Cc: Huzhibo <[email protected]>; Aijun Wang <[email protected]>; Tony Li
<[email protected]>; lsr <[email protected]>; Tianran Zhou <[email protected]>
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:[email protected]]
Sent: Thursday, March 4, 2021 6:50 PM
To: wangyali <[email protected]>; Gyan Mishra
<[email protected]>; Robert Raszuk <[email protected]>
Cc: Huzhibo <[email protected]>; Aijun Wang
<[email protected]>; Tony Li <[email protected]>; lsr
<[email protected]>; Tianran Zhou <[email protected]>
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:[email protected]]
Sent: Wednesday, March 3, 2021 5:37 PM
To: wangyali <[email protected]>; Gyan Mishra
<[email protected]>; Robert Raszuk <[email protected]>
Cc: Huzhibo <[email protected]>; Aijun Wang
<[email protected]>; Tony Li <[email protected]>; lsr
<[email protected]>; Tianran Zhou <[email protected]>
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.
- by using the same LSDB to store the MFI specific information only a
limited separation can be achieved. Multi-instance gives you better
separation.
- you carved the MFI specific LSP space from the common LSP space. This
may result in the non routing apps consuming the space that would
otherwise be required for regular routing information, compromising the
basic functionality of the protocol. Multi-instance does not have that
problem.
my 2c,
Peter
thanks,
Peter
thanks,
Peter
thanks,
Peter
Best,
Yali
-----Original Message-----
From: Peter Psenak [mailto:[email protected]]
Sent: Tuesday, March 2, 2021 5:12 PM
To: wangyali <[email protected]>; Gyan Mishra
<[email protected]>; Robert Raszuk <[email protected]>
Cc: Huzhibo <[email protected]>; Aijun Wang
<[email protected]>; Tony Li <[email protected]>; lsr
<[email protected]>; Tianran Zhou <[email protected]>
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:[email protected]]
Sent: Sunday, February 28, 2021 8:23 PM
To: Gyan Mishra <[email protected]>; Robert Raszuk
<[email protected]>
Cc: Huzhibo <[email protected]>; Aijun Wang
<[email protected]>; Tony Li <[email protected]>; lsr
<[email protected]>; Tianran Zhou <[email protected]>; wangyali
<[email protected]>
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 <[email protected]
<mailto:[email protected]>> 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 <[email protected]
<mailto:[email protected]>> 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 <[email protected]
<mailto:[email protected]>> 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.
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