Re: [CCAMP] Comment on compatibility in draft-takacs-ccamp-revertive-ps

[John E Drake <[e-mail]>]

Huub,

A nice note.  Dou you think this draft is gilding the lily?

Yours Irrespectively,

John

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On Behalf
> Of Huub van Helvoort
> Sent: Wednesday, November 13, 2013 12:53 PM
> To: [e-mail]
> Subject: Re: [CCAMP] Comment on compatibility in draft-takacs-ccamp-
> revertive-ps
> 
> Hello Zafar,
> 
> You wrote:
> 
>  > The default parameter value in data plan is deficient for the  > following
> reasons:
> >
> >  1. We cannot differentiate between revertive and non-revertive behavior
> >     using default value of wait-to-restore timer.
> 
> The value of the WTR timer should not determine the (non-)revertive behavior.
> The (non-)revertive behaviour should be explicitly provisioned.
> 
> >     E.g., as far
> >     as I remember default value for WRT is 0, which means protection
> >     is non-revertive.
> 
> The typical default value for WTR is 5 minutes to provide a hysteresis, it can be
> overruled by a higher priority event like Sf or SD.
> Setting the value of WTR to 0 does not mean protection is non-revertive.
> 
> >     So this default does not work for revertive
> >     protection. I.e., the data plan default cannot cover both revertive
> >     and non-revertive cases.
> 
> Again: the WTR value should not be used to indicate (non-)revertive behavior.
> 
> >  2. Correct setting for wait-to-restore and hold-off timers need to
> >     account for differential delays between working and protection paths.
> 
> No, WTR accounts for repair of the failed path and to encertain that the repair
> can be trusted.
> Hold-off timers are used to allow protection switching in layers closer to the
> physical layer to complete before protection switching in the affected layer.
> 
> > In summary, default values cannot cover all use cases. Hence, SP
> > typically wants to set revertive vs. non-revertive behavior,
> > wait-to-restore and hold-off timers on per connection basis.
> 
> They will provision default values per layer in the network.
> 
> Regards, Huub.
> 
> ===========
> > From: Dieter Beller <[e-mail]
> > <mailto:[e-mail]>>
> > Organization: Alcatel-Lucent
> > Date: Sunday, November 10, 2013 9:07 AM
> > To: zali <[e-mail] <mailto:[e-mail]>>
> > Cc: "[e-mail] <mailto:[e-mail]>" <[e-mail]
> > <mailto:[e-mail]>>, "[e-mail] <mailto:[e-mail]>"
> > <[e-mail] <mailto:[e-mail]>>
> > Subject: Re: [CCAMP] Comment on compatibility in
> > draft-takacs-ccamp-revertive-ps
> >
> >     Hi Zafar,
> >
> >     this draft is defining signaling extensions for the hold-off time as
> >     well as the wait-to-restore time for protected LSPs
> >     where applicable.
> >
> >     There are default values set for these timers in the data plane and
> >     signaling them in the control plane makes only
> >     sense if the timer values shall differ from the default values. Do
> >     you see a need for that? IMO, operators typically
> >     use the defaults and do not set these values on a per connection basis.
> >
> >
> >     Thanks,
> >     Dieter
> >
> >
> >     On 08.11.2013 22:11, Zafar Ali (zali) wrote:
> >>     Hi Lou-
> >>
> >>     You are right, the ctype is TBD, like I mentioned during the meeting that
> >>     we are using different ctype.
> >>
> >>     We would like to take this opportunity to solicit comments from the WG
> on
> >>     this draft.
> >>
> >>     Thanks
> >>
> >>     Regards Š Zafar
> >>
> >>     -----Original Message-----
> >>     From:"[e-mail]"  <[e-mail]>
> >>     Date: Thursday, November 7, 2013 6:17 PM
> >>     To: zali<[e-mail]>,"[e-mail]"  <[e-mail]>
> >>     Subject: Comment on compatibility in
> >> draft-takacs-ccamp-revertive-ps
> >>
> >>>     Zafar,
> >>>     	My comment in today's session was that you are redefining the format
> of
> >>>     an existing object (by adding TLVs) this breaks compatibility.  You
> >>>     stated that this wasn't the case.
> >>>
> >>>     FWIW:
> >>>
> >>>     Your document says:
> >>>
> >>>         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
> >>>        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >>>        |            Length             | Class-Num(37) |   C-Type(2)   |
> >>>        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >>>        |S|P|N|O| Reserved  | LSP Flags |      Reserved     | Link Flags|
> >>>        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >>>        |I|R|   Reserved    | Seg.Flags |           Reserved            |
> >>>        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >>>        |                                                               |
> >>>        ~                           sub-TLVs                            ~
> >>>        |                                                               |
> >>>
> >>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >>>
> >>>
> >>>     RFC4872 says
> >>>           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
> >>>          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >>>          |            Length             | Class-Num(37) | C-Type (2)    |
> >>>          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >>>          |S|P|N|O| Reserved  | LSP Flags |     Reserved      | Link Flags|
> >>>          +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >>>          |                           Reserved                            |
> >>>
> >>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> >>>
> >>>     Perhaps you meant C-Type(TBD).  You should address compatibility
> >>>     explicitly in any case.
> >>>
> >>>     Lou
> >>     _______________________________________________
> >>     CCAMP mailing list
> >>     [e-mail]://www.ietf.org/mailman/listinfo/ccamp
> >
> 
> 
> --
> ***************************************************************
> **
>                请记住，你是独一无二的，就像其他每一个人一样
> _______________________________________________
> CCAMP mailing list
> [e-mail]
> https://www.ietf.org/mailman/listinfo/ccamp