Re: [Detnet-dp-dt] Draft update in github

[Loa Andersson <[e-mail]>]

Jouni,

I was working on reviewing the previous version, I see that
you captured most of (very close to sll<9 of the comments I had.

Questions:

1. IETF is mostly doing "on the wire" specifications, what is in the
box is mostly viewed as implementation specific. Against this background
why do we need "local-ID", isn't that implementation specific?

2. There are two sentences "In the context of this document DA-T-PE is
referred as T-PE." and "In the context of this document DA-S-PE is 
referred as S-PE." Wouldn't it be better to actually use the new
abbreviations, DA-T-PE and DA-S-PE?

3. Then I wonder if you got what is optional in the label stack
and what is not; what needs to be there is one single tunnel, we have
called that L-labels (PW architecture call it PSN Tunnel) all the rest
of the T-Label tunnels are  optional.

I wrote it down like this:

    +-------------------------------+
    |                               |
    |          DetNet Flow          |
    |            Payload            |  n octets
    |                               |
    +-------------------------------+
    |      DetNet Flow Id           |  4 octets
    +-------------------------------+
    |      DetNet Control Word      |  4 octets
    +-------------------------------+
    |          MS-PW Label          |  4 octets
    +-------------------------------+
    |            L-Label            |  4 octets
    +-------------------------------+
    |   (optional) MPLS T-Label(s)  |  n*4 octets (four octets per label)
    +-------------------------------+


DetNet Flow Payload - n octets
DetNet Flow Id      - 4 octets, part of the encapsualtion header,
                       i.e. not in the label stack
DetNet Control Word - 4 octets, the 16 least significant but are a
                       a sequence number.
MS-PW Label         - 4 octets, this label is unchanged between two
                       DA-x-PEs, and at PW set up it is decided if
                       the Native Service Processing includes DetNet
                       FRER or not, the MS-PW Label is swapped at
                       DA-S-PE.
L-Label             - carries the MS-PW Label unchanged from one
                       DA-x-PE to the next
T-Label(s)          - are optional, and strictly not part of the
                       DetNet encapsulation.

I don't want you to change but maybe capture a few bits and pieces
from this.

Then I have one ridiculous concern, the DA-S-PE does not need to 
interface a CE, and does not necessarily sit on a domain border, and is
tthus not necessary a "real" PE. If we ant to keep calling it a PE
(I think we should), we should have some words around this.


/Loa


On 2017-03-10 12:55, Jouni Korhonen wrote:
> Folks,
>
> I did quite a bit of updates to the draft. All in GitHub. I’ll continue writing over the weekend etc..
>
> - Jouni
>
>

-- 


Loa Andersson                        email: [e-mail]
Senior MPLS Expert                          [e-mail]
Huawei Technologies (consultant)     phone: [phone]