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

["Zafar Ali (zali)" <[e-mail]>]

Hi Dieter:

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. E.g., as far as I remember default value for WRT is 0, which means 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.
  2.  Correct setting for wait-to-restore and hold-off timers need to account for differential delays between working and protection paths.

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.

Thanks

Regards … Zafar

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]"<mailto:[e-mail]> <[e-mail]><mailto:[e-mail]>
Date: Thursday, November 7, 2013 6:17 PM
To: zali <[e-mail]><mailto:[e-mail]>, "[e-mail]"<mailto:[e-mail]> <[e-mail]><mailto:[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


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