Hi, Aijun and Chiris
Some personal understanding to share. If any misunderstanding, please
correct me. Thanks in advance.
I agree that the MP-TLV in draft-ietf-lsr-multi-tlv can work here.
However, I agree that we also need a more general way.
In addition, I suggest we can have a container TLV with a CSN (container
sequence number). Therefore, it create anther layer for the encapsulation of
the big TLV.
Perhaps it has similar function to the Identification in the current
draft-wang-lsr-isis-big-tlv . I do not think they are very completed. Perhaps
more discussion is needed here.
For example, we have a TLV type 16 and length 16, we can encapsulate it in
several container TLVs with type 8 and length 8.
Figure1: A type 16 and length 16 TLV
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (T) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --+ | Piece 1 (less than
248 octets)| | ~
~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Piece 2 (less
than 252 octets)| | ~
~ Bigger than
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 255 octets ~
: ~ |
~ . ~
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Piece n (less than 252 octets)| |
~ ~
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --+
After encapsulation 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --+
| Type (TBD1) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --+
| container sequence number =1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
Type (T) =16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
Length =16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Piece 1 (less than 248
octets)| | ~ ~
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --+
| Type (TBD1) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --+
| container sequence number =2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Piece 2 (less than 252
octets)| | ~ ~
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --+
| Type (TBD1) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ --+
| container sequence number =n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Piece n (less than 252
octets)| | ~ ~
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Best Regards
Zongpeng Du
[email protected] & [email protected]
From: Aijun Wang
Date: 2024-10-28 16:22
To: 【外部账号】Christian Hopps
CC: Hannes Gredler; Aijun Wang; Yingzhen Qu; lsr-chairs;
draft-wang-lsr-isis-big-tlv; lsr
Subject: [Lsr] Re: [Further Discussion]It's time to find one general solution
to Big-TLV problem Re: IETF 121 LSR Slot Requests
Hi, Chris:
Let’s discuss your proposal and Les’s responses more further.
First, depending on RFC7356 to solve the potential problem is not
practicable—You must define all the new types for possible big IS-IS TLV, and
also their relevant sub-TLVs.
It’s obviously not the candidate solution.
On the contrary, the updated Big-TLV
proposal(https://datatracker.ietf.org/doc/draft-wang-lsr-isis-big-tlv/) needs
only to define one new generic TLV to solve all possible big-TLV problem, and
also their sub-TLVs.
Second, regarding to Les’s responses at
https://mailarchive.ietf.org/arch/msg/lsr/iL-3bd3LC9ZfYftZUyky3bWyX4E/:
“ This is why some RFCs left the choice in such cases to the implementor.
I mention this only to avoid an argument about trying to retrofit this model to
codepoints where this choice was not made. It isn’t worth the trouble and would
instantly render some implementations non-conformant without significant
benefit.”
It’s possible that there are in private negotiation among different vendors
when there are interoperability issues from such implicit “what constitutes a
key”, such situations will be deteriorated when these TLV/sub-TLVs are sliced
according to the MP-TLV proposal.
The MP-TLV proposal will amplify such non-conformant issues.
It’s time to find one general solution to Big-TLV problem.
Aijun Wang
China Telecom
Aijun Wang
China Telecom
On Oct 26, 2024, at 20:09, 【外部账号】Christian Hopps <[email protected]> wrote:
Hannes Gredler <[email protected]> writes:
Why are we having this discussion again ?
My recollection is that we have a “good enough” solution that is
deployed and interoperable.
If you want the “generic solution” then the 16-bit TLVs described in
RFC7356 is the way to go forward and if there is concern about
incremental deployment then we should work on this aspect.
I also believe the 16 bit solution is the way forward if people wish to do any
more on this at this point.
Thanks,
Chris.
[as wg-member]
/hannes
On 23.10.2024, at 00:50, Aijun Wang <[email protected]>
wrote:
Hi,Chris:
Please elaborate clearly your technical reviews for the updates
of the newly proposed Big-TLV solution.
I can copy the updates again at here and state their effects
clearly.(https://mailarchive.ietf.org/arch/msg/lsr/
dxK4Gy1WDR7QCXK6p58xgA0MdUc/ )Please give your analysis before
you make any conclusions:
A new version of Big-TLV document has been
posted(https://datatracker.ietf.org/doc/html/draft-wang-lsr-isis-big-tlv), to
try to give the community one general way to solve the Big TLV problem.
The main changes from the previous versions are the followings:
1) Add one "Identification" field within the container TLV(type TBD1), to
function as the key for any sliced TLV, and is TLV code point independent.
2) Add one "Flag" field, define currently the "F" bit to indicate whether
the piece of container is the first piece(F bit is set to 1), or not (F bit is
unset)
3) Put all the sliced pieces within the newly defined container TLV(type
TBD1).
4) Define some rules for the "Split and Glue" procedures(may be re-optimizer
later after the WG discussions)
The updated version erases the necessity of defining the "key" information
for every IS-IS (Possible Big) TLV code point, and also the necessity of
per-TLV capability announcement.
I would like to hear your detail analysis, especially as the WG chairs, for
the above statements.
Aijun Wang
China Telecom
On Oct 22, 2024, at 20:15, 【外部账号】Christian Hopps
<[email protected]> wrote:
Those changes don't appear to address what the WG already
decided against. The view of the WG was that a new Big TLV
for doing this was not going to work. Given the name of this
work is Big TLV, that doesn't seem to have changed. So why
should the WG be spending even more time on a solution they
already discussed, debated and discarded?
Thanks,
Chris.
[as wg chair]
On Oct 22, 2024, at 06:47, Aijun Wang
<[email protected]> wrote:
Hi, Chris:
No, we have made some significant updates.
Please refer to https://mailarchive.ietf.org/arch/msg/lsr
/dxK4Gy1WDR7QCXK6p58xgA0MdUc/ for more information.
Aijun Wang
China Telecom
On Oct 22, 2024, at 17:04, 【外部账号】Christian
Hopps <[email protected]> wrote:
Is this the same thing that Huaimo has already
presented to the WG, that the WG decided was not the
way it wanted to go?
Thanks,
Chris.
"Aijun Wang" <[email protected]> writes:
Hi, Yingzhen:
I would like to request 10-15minutes to make the
presentation for the
“IS-IS Extension for Big TLV”
The related information are the followings:
Draft Name: IS-IS Extension for Big TLV
Link: https://datatracker.ietf.org/doc/
draft-wang-lsr-isis-big-tlv
/
Presenter: Aijun Wang
Desired Slot Length: 10-15minutes.
Best Regards
Aijun Wang
China Telecom
发件人: [email protected]
[mailto:[email protected]] 代表
Yingzhen Qu
发送时间: 2024年10月12日 3:54
收件人: lsr <[email protected]>; lsr-chairs
<[email protected]>
主题: [Lsr] IETF 121 LSR Slot Requests
Hi,
The draft agenda for IETF 121 has been posted:
IETF 121 Meeting Agenda
The LSR session is scheduled on Thursday Session
I 09:30-11:30, Nov 7th, 2024.
Please send slot requests to [email protected]
before the end of the day
Wednesday Oct 23. Please include draft name and
link, presenter, desired
slot length including Q&A.
Thanks,
Yingzhen
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