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Date: Fri, 6 Jul 2012 12:18:03 -0700
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From: David Meyer <dmm@1-4-5.net>
To: "Andrew G. Malis" <amalis@gmail.com>
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Cc: Vladimir Kleiner <Vladimir.Kleiner@ecitele.com>,
 Andrew Sergeev <Andrew.Sergeev@ecitele.com>,
 Idan Kaspit <Idan.Kaspit@ecitele.com>,
 Mishael Wexler <Mishael.Wexler@ecitele.com>, Jan Medved <jmedved@cisco.com>,
 "pwe3@ietf.org" <pwe3@ietf.org>, Andrew McLachlan <andrew@happypig.org>,
 Rotem Cohen <Rotem.Cohen@ecitele.com>
Subject: Re: [PWE3] draft-medved-pwe3-of-config-00.txt posted, review please
Precedence: list

Thanks Andy, will definitely do that. --dmm


On Fri, Jul 6, 2012 at 11:47 AM, Andrew G. Malis <amalis@gmail.com> wrote:
> Dave,
>
> One other comment that just occurred to me as you're working on your
> update - the current revision of the draft obviously only works with
> single-segment PWs, but that's not explicitly stated anywhere, other
> than being alluded to in the title of figure 1. You may wish to make
> that restriction explicit, unless you do intend to include MS-PWs in a
> future revision, in which case that should be made clear as well.
>
> Cheers,
> Andy
>
> On Fri, Jul 6, 2012 at 2:35 PM, David Meyer <dmm@1-4-5.net> wrote:
>> Excellent comments/clarifications Sasha. Thanks, really appreciate it
>> and I'll work this into the next rev (working on that now).
>>
>> --dmm
>>
>>
>> On Fri, Jul 6, 2012 at 11:29 AM, Alexander Vainshtein
>> <Alexander.Vainshtein@ecitele.com> wrote:
>>> David,
>>> Please see a couple of comments inline below. Hopefully they clarify my=
 position.
>>>
>>> I have snipped some fragments of your response to make the remaining te=
xt more readable.
>>>
>>> Regards,
>>>      Sasha
>>>
>>> ________________________________________
>>> From: David Meyer [dmm@1-4-5.net]
>>> Sent: Friday, July 06, 2012 4:59 PM
>>> To: Alexander Vainshtein
>>> Cc: Andrew G. Malis; Jan Medved; Andrew McLachlan; pwe3@ietf.org; Misha=
el Wexler; Rotem Cohen; Gideon Agmon; Andrew Sergeev; Idan Kaspit; Vladimir=
 Kleiner
>>> Subject: Re: [PWE3] draft-medved-pwe3-of-config-00.txt posted, review p=
lease
>>>
>>> Alexander,
>>>
>>>
>>> On Tue, Jul 3, 2012 at 10:05 PM, Alexander Vainshtein
>>> <Alexander.Vainshtein@ecitele.com> wrote:
>>>> Andy and all,
>>>>
>>>> I've looked up the draft in question, and I have some comments/questio=
ns in
>>>> addition to Andy's:
>>>>
>>>> The PWE3 WG has defined multiple MIBs that can be used for PW setup an=
d
>>>> teardown by a      management application (MPLS-TP or not). IMO the dr=
aft
>>>> should indicate that the method proposed there is an alternative not j=
ust to
>>>> PW signaling via T-LDP (as Andy has said) but also to static PW setup =
using
>>>> these MIBs.
>>>
>>> As I mentioned, the draft did not intended to provide an alternate
>>> control plane; hopefully that will be clear in the next rev. I'll add
>>> some text around the point you make WRT MIBs above.
>>>
>>> [[Sasha]] Well, MIBs are not part of control plane (at least, for me), =
but of the Management Plane - and, to the best of my understanding, so is O=
penFlow. But putting terminology aside, the PWE3 MIBs provide a certain abs=
tract model of the PW endpoints that is integrated with the existing model =
for MPLS etc.
>>> Your draft seems to offer an alternative abstract model that seems to m=
ix PW and MPLS functionality.
>>>
>>> --- snipped --
>>>
>>>> The PWs run in in MPLS (or MPLS-TP) tunnels in order to improve scalab=
ility of
>>>> P routers, because the same tunnel between a given pair of PEs can be =
shared
>>>> by multiple PW instances. It is not clear from the text how such shari=
ng can
>>>> be accommodated in the proposed OF switch model.
>>>
>>> Humm, here is nothing that stops the "transport virtual port" from
>>> sharing transport labels if that is appropriate. Perhaps I'm not
>>> understanding your point?
>>>
>>> [[Sasha]] What is important is that multiple PWs sharing a common MPLS =
tunnel LSP are fate-sharing in the PSN core, and the model should IMHO refl=
ect this fact explicitly. E.g., the protection switch is applied to tunnel =
LSPs, not to individual PWs. This affects both the management aspects (e.g.=
, failures of individual PWs sharing a tunnel LSP should be suppressed when=
 the tuneel LSP fails) and the data plane (e.g., the time it takes to compl=
ete a protection switch triggered by the tunnel LSP failure should not depe=
nd upon the number of PWs using this tunnel LSP). IMHO and FWIW the model w=
here each PW uses its individual "transport virtual ports" does not make th=
is easy (if at all possible) even if you allow sharing of labels between th=
ee ports. Or do I miss something?
>>>
>>> --- snipped to the end ---
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