Re: [mpls] Extension headers structure

[Vasilenko Eduard <[e-mail]>]

Hi Jeffrey,

Yes, “T” means “Type of the Next”. I believe that many data planes have the same meaning now for T. They still call it T, not nT. But it is not principal.
And yes, the last one is better to be from IP protocol number space (pointing to IPv6/v4).
Strictly speaking, my proposal is not TLV, but TOV (Offset), Where TO and V are in different places. But of course, they are related to each other.

Look below at my proposal for your draft: the last T should be from IP protocol space – no problem.
My proposition for your draft could be encoded as “Zero:T:TLV…TLV”
If you would accept what I have proposed to you below then T would mean “Type of the Next” for all solutions discussed here.
It is right because our last T should point to IP protocol.

I am strictly opposite “headers of headers”. This concept has killed IPv6 EH. Much bigger complexity for hardware. Guys producing half-routers/half-switches would not implement it for the next X>Y years.
I propose to keep MPLS EH in the flat stricture: one-by-one without hierarchy.

Ed/
From: Jeffrey (Zhaohui) Zhang [mailto:[e-mail]]
Sent: Thursday, April 22, 2021 9:36 PM
To: Vasilenko Eduard <[e-mail]>; Haoyu Song <[e-mail]>; [e-mail]
Subject: RE: Extension headers structure

Hi Haoyu,

If the concept of Header of headers is important (e.g., so that we can quickly find the start of real payload), it can be incorporated into GDF as well – we can define a “GDFH container” type for “this header” and pack all contiguous GDFHs into it.

Hi Eduard,

If I understand you correctly, yours is not TLV (where the T indicates the type of *this* block), but nTLV, where nT indicates the type of *next* block. I am not saying that is unreasonable, but want to clarify it.

The intention of GDFH is to make it applicable to different layers, so it has the “next header” from the IP protocol number space and the “this header” from its own space.

Thanks.
Jeffrey



From: mpls <[e-mail]<mailto:[e-mail]>> On Behalf Of Vasilenko Eduard
Sent: Thursday, April 22, 2021 2:14 PM
To: Haoyu Song <[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]>
Subject: Re: [mpls] Extension headers structure

[External Email. Be cautious of content]

Hi Haoyu,
In reality, your HEH is half of the step to what I propose (Catalog). Hence, I like it more that was discussed today.
It permits to find of the end of all MPLS headers without parsing everything. It is already the big added value for the P that may need to look to IP layer for whatever reason.
By the way, EHTLEN in your case is Offset in reality.

I propose to move all TLs to the fixed structure in front and convert Lengths to Offsets.
Selective headers processing is the flexibility that is better to have.
Extension headers structure would be “Zero:TO…TO:V…V”

Eduard
From: Haoyu Song [mailto:[e-mail]]
Sent: Thursday, April 22, 2021 8:22 PM
To: Vasilenko Eduard <[e-mail]<mailto:[e-mail]>>; [e-mail]<mailto:[e-mail]>
Subject: RE: Extension headers structure

Hi Eduard and all,

Unless I misunderstood something, the following proposal (using TLV instead of the redundant LTTV) has been described in our MPLS Extension Header drafts. In addition, we use a Header of EH to summarize the number and size of the following extension headers, as well as the type of the first extension header.
https://datatracker.ietf.org/doc/draft-song-mpls-extension-header/<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/draft-song-mpls-extension-header/__;!!NEt6yMaO-gk!UcPfvQUsT8y6JuiIbJIZK5-vx91IHV4oT4uxIR5hEqwWqK-zXutIGP2bROzCB-EQ$>

Since we have started to discuss individual proposals, I’ll also request the moderator to add an agenda item in the next meeting so I can give a detailed introduction of the MPLS extension header drafts.

Thanks,
Haoyu

From: mpls <[e-mail]<mailto:[e-mail]>> On Behalf Of Vasilenko Eduard
Sent: Thursday, April 22, 2021 10:01 AM
To: [e-mail]<mailto:[e-mail]>
Subject: [mpls] Extension headers structure


Hi all,

About today's discussion.

I would like to discuss at the subsequent meeting a completely different proposal that I am not sure you would accept.

Hence, it makes sense to improve the current one. I am not happy about “0LTTV” structure: redundant “0” and one “T” in every extension header.

It is just a matter of human interpretation - it does not have any difference for hardware. I propose to return to the “TLV” structure.

Look to the attached - it is a little animated. But the essence is probably possible to understand from this picture:

[cid:[e-mail]6B500]



Except for alignment. If you are sure that alignment is always possible for the MPLS stack - then the current proposal makes sense.
(I did not say the better – I still prefer less redundancy).



Eduard

-----Original Message-----
From: mpls [mailto:[e-mail]] On Behalf Of Fomin, Sergey (Nokia - US/Mountain View)
Sent: Thursday, April 22, 2021 3:57 AM
To: Tarek Saad <tsaad=[e-mail]<mailto:tsaad=[e-mail]>>; [e-mail]<mailto:[e-mail]>
Cc: [e-mail]<mailto:[e-mail]>
Subject: Re: [mpls] Reminder on MPLS Open DT



Hi Tarek,

I'm a bit lost between "track1" and "track2" scopes..



Wiki says:

              Week 2 and 4: Track 1 "Below the BoS"

              Week 3 and 5: Track 2 "Above the BoS"



And the agenda looks like some mix of the two?



--

Sergey





-----Original Message-----

From: mpls <[e-mail]<mailto:[e-mail]>> On Behalf Of Tarek Saad

Sent: Wednesday, April 21, 2021 12:16 PM

To: [e-mail]<mailto:[e-mail]>

Cc: [e-mail]<mailto:[e-mail]>

Subject: Re: [mpls] Reminder on MPLS Open DT



Hi WG,



A tentative agenda for tomorrow's Open MPLS DT meeting is posted at:

https://trac.ietf.org/trac/mpls/wiki/track2<https://urldefense.com/v3/__https:/nam11.safelinks.protection.outlook.com/?url=https*3A*2F*2Ftrac.ietf.org*2Ftrac*2Fmpls*2Fwiki*2Ftrack2&data=04*7C01*7Chaoyu.song*40futurewei.com*7C4db9ab82c0284306a60b08d905b0462a*7C0fee8ff2a3b240189c753a1d5591fedc*7C1*7C0*7C637547076938223342*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C1000&sdata=GRXgwIglG1YUhN0mJx1Ea*2B8XYLab*2FbPUull8L3WHt9M*3D&reserved=0__;JSUlJSUlJSUlJSUlJSUlJSUlJSUlJQ!!NEt6yMaO-gk!UcPfvQUsT8y6JuiIbJIZK5-vx91IHV4oT4uxIR5hEqwWqK-zXutIGP2bRHZfUM45$>



Let me know if you want to add a discussion point.



Regards,

Tarek (for mpls wg chairs)





On 4/19/21, 10:58 AM, "Tarek Saad" <[e-mail]<mailto:[e-mail]>> wrote:



    All,



    I added some minutes taken during the 1st meeting we held on 4/8 at:

    https://trac.ietf.org/trac/mpls/wiki/meeting20210408<https://urldefense.com/v3/__https:/nam11.safelinks.protection.outlook.com/?url=https*3A*2F*2Ftrac.ietf.org*2Ftrac*2Fmpls*2Fwiki*2Fmeeting20210408&data=04*7C01*7Chaoyu.song*40futurewei.com*7C4db9ab82c0284306a60b08d905b0462a*7C0fee8ff2a3b240189c753a1d5591fedc*7C1*7C0*7C637547076938233337*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C1000&sdata=LCtkR54sgUB*2B6OPmJH23nOdvulrqc1tv*2FIC*2BIVzpLFM*3D&reserved=0__;JSUlJSUlJSUlJSUlJSUlJSUlJSUlJSU!!NEt6yMaO-gk!UcPfvQUsT8y6JuiIbJIZK5-vx91IHV4oT4uxIR5hEqwWqK-zXutIGP2bRILavBB7$>



    Regards,

    Tarek/wg chairs



    On 4/13/21, 12:08 PM, "Loa Andersson" <[e-mail]<mailto:[e-mail]>> wrote:



        Design Team'





        We have our first Track 1 meting on 2021-04-15.



        The agenda will be found at:



        https://trac.ietf.org/trac/mpls/wiki/track1-agenda<https://urldefense.com/v3/__https:/nam11.safelinks.protection.outlook.com/?url=https*3A*2F*2Ftrac.ietf.org*2Ftrac*2Fmpls*2Fwiki*2Ftrack1-agenda&data=04*7C01*7Chaoyu.song*40futurewei.com*7C4db9ab82c0284306a60b08d905b0462a*7C0fee8ff2a3b240189c753a1d5591fedc*7C1*7C0*7C637547076938233337*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C1000&sdata=PHh1icBtINZAXkBmIZJewVH*2FqAMr*2F25niasEUq6Ez6Q*3D&reserved=0__;JSUlJSUlJSUlJSUlJSUlJSUlJSUlJQ!!NEt6yMaO-gk!UcPfvQUsT8y6JuiIbJIZK5-vx91IHV4oT4uxIR5hEqwWqK-zXutIGP2bRI2Ln_DH$>



        WebEx info:





        https://mailarchive.ietf.org/arch/msg/mpls/jU7XZe9UeTQYU_SVSd0qT4YRAZU/<https://urldefense.com/v3/__https:/nam11.safelinks.protection.outlook.com/?url=https*3A*2F*2Fmailarchive.ietf.org*2Farch*2Fmsg*2Fmpls*2FjU7XZe9UeTQYU_SVSd0qT4YRAZU*2F&data=04*7C01*7Chaoyu.song*40futurewei.com*7C4db9ab82c0284306a60b08d905b0462a*7C0fee8ff2a3b240189c753a1d5591fedc*7C1*7C0*7C637547076938243330*7CUnknown*7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0*3D*7C1000&sdata=1pa7cJfgcBvnKq1CDfBSb9Zscr6*2FAPqcWaKBp*2B7WLAw*3D&reserved=0__;JSUlJSUlJSUlJSUlJSUlJSUlJSUlJSU!!NEt6yMaO-gk!UcPfvQUsT8y6JuiIbJIZK5-vx91IHV4oT4uxIR5hEqwWqK-zXutIGP2bRA9MUsOe$>



        Loa/wg chairs



        --



        Loa Andersson                        email: [e-mail]<mailto:[e-mail]>

        Senior MPLS Expert                          [e-mail]<mailto:[e-mail]>

        Bronze Dragon Consulting             phone: [phone]





    Juniper Business Use Only





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