Re: [mpls] draft-zzhang-intarea-generic-delivery-functions

[Stewart Bryant <[e-mail]>]

What happens if an operator wants to run both iOAM and GDFH at the same time and the packet is a PW packet?

What does the packet look like and how does the forwarder know what to do?

- Stewart

> On 22 Feb 2021, at 22:49, Jeffrey (Zhaohui) Zhang <[e-mail]> wrote:
> 
> Hi Stewart,
>  
> This thread started with your comment “Please see the note that I sent about iOAM who also want to sit after BoS … and both of you want the same space that PALS and DetNet is already using”, but now it seems that we’re on the same page – GDFH starting with 0000b is fine and is not competing with IOAM or PW/DETNET CW?
>  
> Thanks.
> Jeffrey
>  
> From: Stewart Bryant <[e-mail] <mailto:[e-mail]>> 
> Sent: Monday, February 22, 2021 5:15 AM
> To: Jeffrey (Zhaohui) Zhang <[e-mail] <mailto:[e-mail]>>
> Cc: Stewart Bryant <[e-mail] <mailto:[e-mail]>>; [e-mail] <mailto:[e-mail]>; mpls <[e-mail] <mailto:[e-mail]>>; [e-mail] <mailto:[e-mail]>; Kireeti Kompella <[e-mail] <mailto:[e-mail]>>; Ron Bonica <[e-mail] <mailto:[e-mail]>>; <[e-mail] <mailto:[e-mail]>> <[e-mail] <mailto:[e-mail]>>
> Subject: Re: draft-zzhang-intarea-generic-delivery-functions
>  
> [External Email. Be cautious of content]
>  
> The DetNet CW is described in RFC8964 and is  
>  
>  
>  
>       0                   1                   2                   3
>       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>      |0 0 0 0|                Sequence Number                        |
>      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
>  
>                        Figure 5: DetNet Control Word
>  
> In all defined control words
>  
> The 0000 is simply ECMP defeat and has no other purpose.
>  
> 0001 means ACH 
>  
> An ACH is currently defined not to carry service/user data - it is a control/OAM channel.
>  
> You cannot assume anything about a payload starting 0000.
>  
> In MPLS the bottom label (alone) defines how you process the payload. So you know that you have a CW from the bottom label and by no other means.
>  
> In other words the the FEC of the bottom label and its associated parameters are the way that signalling protocol knows what instructions to give the forwarder, and the way that the forwarder knows what to do with the packet is from the instructions associated with the BoS label. This is the universal model for MPLS including for IP packets.
>  
> Stewart
>  
>  
> On 19 Feb 2021, at 15:42, Jeffrey (Zhaohui) Zhang <[e-mail] <mailto:[e-mail]>> wrote:
>  
> Hi Stewart,
> 
> I still have to read more about DetNet, but I am not sure if there is a real contention with PALS.
> 
> My understanding of 0000 nibble in PW control world is that it is only to prevent a transit node from mistaking the payload as IP. Is it supposed to indicate that any payload starting with 0000 is PW payload? I hope not.
> 
> Use of 0000 nibble in GDFH is also just to prevent transit nodes from mistaking it as IP. It does indicate it is GDFH. It should be able to co-exist with PW CW.
> 
> Thanks.
> Jeffrey
> 
> -----Original Message-----
> From: Jeffrey (Zhaohui) Zhang
> Sent: Thursday, February 18, 2021 10:35 PM
> To: Stewart Bryant <[e-mail] <mailto:[e-mail]>>
> Cc: [e-mail] <mailto:[e-mail]>; mpls <[e-mail] <mailto:[e-mail]>>; [e-mail] <mailto:[e-mail]>; Kireeti Kompella <[e-mail] <mailto:[e-mail]>>; Ron Bonica <[e-mail] <mailto:[e-mail]>>; <[e-mail] <mailto:[e-mail]>> <[e-mail] <mailto:[e-mail]>>
> Subject: RE: draft-zzhang-intarea-generic-delivery-functions
> 
> Stewart, all,
> 
> I apologize for not responding to this in time. I some how accidentally moved a few wg mailing list email folders to a place where I could not see so I missed all the discussions.
> Let me catch up all the emails and then reply.
> 
> Thanks.
> Jeffrey
> 
> -----Original Message-----
> From: Stewart Bryant <[e-mail] <mailto:[e-mail]>>
> Sent: Tuesday, January 12, 2021 9:59 AM
> To: Jeffrey (Zhaohui) Zhang <[e-mail] <mailto:[e-mail]>>
> Cc: Stewart Bryant <[e-mail] <mailto:[e-mail]>>; [e-mail] <mailto:[e-mail]>; mpls <[e-mail] <mailto:[e-mail]>>; [e-mail] <mailto:[e-mail]>; Kireeti Kompella <[e-mail] <mailto:[e-mail]>>; Ron Bonica <[e-mail] <mailto:[e-mail]>>; <[e-mail] <mailto:[e-mail]>> <[e-mail] <mailto:[e-mail]>>
> Subject: Re: draft-zzhang-intarea-generic-delivery-functions
> 
> [External Email. Be cautious of content]
> 
> 
> Thank you Jeffery
> 
> Please see the note that I sent about iOAM who also want to sit after BoS … and both of you want the same space that PALS and DetNet is already using.
> 
> We plan to have a joint session on this hosted by PALS at the next IETF, but I think we also need to include the iOAM people.
> 
> This has scope to get very messy as we find new candidates for BoS metadata so we really need to take a holistic position to ensure the future health the MPLS protocol.
> 
> - Stewart
> 
> 
> 
> On 12 Jan 2021, at 14:27, Jeffrey (Zhaohui) Zhang <[e-mail] <mailto:[e-mail]>> wrote:
> 
> Hi,
> 
> I just posted https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft-zzhang-intarea-generic-delivery-functions/__;!!NEt6yMaO-gk!QyBnufJO58LP6Diq96EdYEe2kxFtiItOdNuXbu_RIMekK2pkpOj4Mmj7b9MseV-Y$ <https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/draft-zzhang-intarea-generic-delivery-functions/__;!!NEt6yMaO-gk!QyBnufJO58LP6Diq96EdYEe2kxFtiItOdNuXbu_RIMekK2pkpOj4Mmj7b9MseV-Y$> .
> 
> The initial version was posted to the tsvwg (https://urldefense.com/v3/__https://tools.ietf.org/html/draft-zzhang-tsvwg-generic-transport-functions-00__;!!NEt6yMaO-gk!QyBnufJO58LP6Diq96EdYEe2kxFtiItOdNuXbu_RIMekK2pkpOj4Mmj7b5lS_Jea$ <https://urldefense.com/v3/__https:/tools.ietf.org/html/draft-zzhang-tsvwg-generic-transport-functions-00__;!!NEt6yMaO-gk!QyBnufJO58LP6Diq96EdYEe2kxFtiItOdNuXbu_RIMekK2pkpOj4Mmj7b5lS_Jea$> ). After discussions/feedback we are re-homing it to intarea wg. This new version also contains quite some changes based on the comments and feedback that we received (special thanks to Stewart).
> 
> Comments and suggestions are appreciated.
> 
> Thanks.
> Jeffrey
> 
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