Subject: Re: [Pals] Mirja Kühlewind's No Objection on draft-ietf-pals-mpls-tp-dual-homing-coordination-05: (with COMMENT)

From: "Mirja Kuehlewind (IETF)" <[email-masked]>
Date: Wed, 1 Mar 2017 12:44:01 +0100

Hi Jie,

thanks for your clarification. Maybe it’s worth adding a few more words for point 2 and 3 in the draft to make it crystal clear. Please do whatever you think is right.

Mirja

> Am 01.03.2017 um 07:50 schrieb Dongjie (Jimmy) <[email-masked]>:
> 
> Hi Mirja, 
> 
> Thanks a lot for your comments. Please see my replies inline.
> 
>> -----Original Message-----
>> From: Mirja Kühlewind [mailto:[email-masked]]
>> Sent: Wednesday, March 01, 2017 12:38 AM
>> To: The IESG <[email-masked]>
>> Cc: [email-masked]; Stewart Bryant
>> <[email-masked]>; [email-masked];
>> [email-masked]; [email-masked]
>> Subject: Mirja Kühlewind's No Objection on
>> draft-ietf-pals-mpls-tp-dual-homing-coordination-05: (with COMMENT)
>> 
>> Mirja Kühlewind has entered the following ballot position for
>> draft-ietf-pals-mpls-tp-dual-homing-coordination-05: No Objection
>> 
>> When responding, please keep the subject line intact and reply to all email
>> addresses included in the To and CC lines. (Feel free to cut this introductory
>> paragraph, however.)
>> 
>> 
>> Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
>> for more information about IESG DISCUSS and COMMENT positions.
>> 
>> 
>> The document, along with other ballot positions, can be found here:
>> https://datatracker.ietf.org/doc/draft-ietf-pals-mpls-tp-dual-homing-coordinati
>> on/
>> 
>> 
>> 
>> ----------------------------------------------------------------------
>> COMMENT:
>> ----------------------------------------------------------------------
>> 
>> Minor mostly editorial comments:
>> 
>> 1) When I first saw "DHC Code Point" in figure 2, I was slightly confused
>> because this doesn't show in the rest of the doc anymore. Maybe rename to
>> 'DHC channel type' or use the same term in the text or directly put the value in
>> there that will be assigned by IANA.
> 
> Thanks for pointing out this. Will change this to "DHC Channel Type" in next revision. 
>> 
>> 2) 3.1.:"After the transmission of the three messages, the
>>   dual-homing PE MUST send the most recently transmitted Dual-Node
>>   Switching TLV periodically to the other dual-homing PE on a continual
>>   basis using the DHC message."
>>   This is only if the protection is active, right?
> 
> Yes, the switching TLV is sent periodically after the protection is in active. 
> 
>> 
>> 3) 3.2.:"Whenever a change of service PW status is detected by a dual-homing
>>   PE, it MUST be reflected in the PW Status TLV and sent to the other
>>   dual-homing PE immediately using the 3 consecutive DHC messages.
>>   This way, both dual-homing PEs have the status of the working and
>>   protection PW consistently."
>>   Note, it's possible that all three messages get lost. If you want to make
>> sure you stay in sync, you need an explicit mechanism for reliability, e.g.
>> sending an ack.
> 
> The 3 consecutive message mechanism is similar to the mechanism defined in section 4.1 of rfc6378 (MPLS-TP linear protection). It can ensure the state exchange if one or two of the 3 messages get lost. And after the 3 consecutive messages, the message will still be transmitted continuously as defined in section 3.1 of this draft, so the dual-homing PEs would stay in sync. 
> 
> Best regards,
> Jie