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

[Loa Andersson <[e-mail]>]

Jouni,

OK - let us know when you upload a new version. The improvements
version by version so far has been great. Did you look at my other
qustions?

/Loa

On 2017-03-10 16:58, Jouni Korhonen wrote:
> Loa,
>
> Correct. I kind of failed to say that :)
>
> - Jouni
>
>
>> On 09 Mar 2017, at 22:36, Loa Andersson <[e-mail]> wrote:
>>
>> Jouni,
>>
>> You say:
>>
>>   Depending on the network topology the "overlay label" may be part of
>>   the label stack.  This "L-label" has actually nothing specific to do
>>   with DetNet but can be used to build overlay topologies over the
>>   provider network in a same way virtual private networks (VPN) are
>>   built.
>>
>> What you sday about overlay topoöogies is correct, butthere is one more
>> characteristic of the L-label it guarantee that the PW-label is
>> unchanged from DA-x-PE to DA-x-PE, a tunnel that does not
>> expose the PW-label other than to the DA-S-PE or the DA-T-PE is not
>> optional, it must be there.
>>
>> /Loa
>>
>>
>> On 2017-03-10 13:58, Loa Andersson wrote:
>>> 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]
>>
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-- 


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