Re: [Gen-art] [dhcwg] RE : Gen-art review: draft-ietf-dhc-triggered-reconfigure-05

["Bernie Volz (volz)" <[e-mail]>]

FYI - Stable storage or some kind of redundancy solution may be another way to recover state. So, I don't think there is a hard requirement for RFC 5460.

I don't think there is a strong reason to avoid e.g., it is "for example" so it is only one of many possible. And "such as" is basically saying the same thing.

---

But then we come to why this is even important ... The original text was:

   This setup assumes the relay has a record of the client, so that it
   has enough information to send the Reconfigure-Request message to the
   server.  How the state is recorded in the relay is out of scope.
   Furthermore, means to recover state in failure events must be
   supported, but are not discussed in this document.

I'm a bit skeptical why this draft even brings the 'recover state' up. Yes, the relay does need to record the client in order to initiate a Reconfigure-Request. But I think the sentence "Furthermore, means to recover state in failure events must be supported, but are not discussed in this document." is not needed. Sure, if the relay has no way of recovering this state, traffic to/from clients will likely not work and certainly if the relay is reconfigured, it will be unable to generate a Reconfigure-Request. But I don't really see this draft needing this requirement. Reconfigure-request could still work until the state is lost. And if the state is lost, there is a lot more than is potentially broken.

But I don't really see this as a big issue and the "must" is the lower-case variant anyway.

- Bernie

-----Original Message-----
From: Robert Sparks [mailto:[e-mail]] 
Sent: Monday, April 29, 2013 9:45 AM
To: [e-mail]
Cc: Bernie Volz (volz); [e-mail]; General Area Review Team; [e-mail]; [e-mail]
Subject: Re: [dhcwg] RE : Gen-art review: draft-ietf-dhc-triggered-reconfigure-05

On 4/29/13 12:59 AM, [e-mail] wrote:
> Robert,
>
> Ted suggested a wording which is better than the one I proposed. I made the following changes my local copy:
>
> (1)
>
> OLD:
>     When retransmission is required, the relay may decide to correct the
>     content of RECONFIGURE-REQUEST message it issues (e.g., update the
>     Client Identifier list).
>
> NEW:
>     The relay MAY remove clients from the client identifier list in
>     subsequent retransmissions, but MUST NOT add clients to the client
>     identifier list.
>
> (2)
>
> OLD:
>     Furthermore, means to recover state in failure events must be
>     supported, but are not discussed in this document.
>
> NEW:
>     Furthermore, means to recover state in failure events (e.g.,
>     [RFC5460]) must be supported, but are not discussed in this document.
>
> Is this better?
1 is better.

2 is an improvement, I might say "such as" instead of e.g. to even more strongly avoid someone thinking you are _requiring_ implementation of RFC5460.  Even then, it's still not clear whether you're trying to say

"Something that doesn't do this is does not conform to this specification"

or

"Something that doesn't do this isn't as good a tool as it can be and may create a condition that operators and users will not like much."

You chose not to use MUST in that sentence. Can you make it less likely that someone will assume you meant to?
>
> Cheers,
> Med
>
>
>> -----Message d'origine-----
>> De : Bernie Volz (volz) [mailto:[e-mail]] Envoyé : samedi 27 
>> avril 2013 06:24 À : Robert Sparks; BOUCADAIR Mohamed OLNC/OLN Cc : 
>> [e-mail]; General Area Review Team; [e-mail]; draft-ietf- 
>> [e-mail]
>> Objet : RE: [dhcwg] RE : Gen-art review: draft-ietf-dhc-triggered-
>> reconfigure-05
>>
>> Robert:
>>
>> The reason to allow this is that otherwise client A will be 
>> unnecessarily reconfigured many times. (It is also possible that a 
>> client might Renew on its own just as this is happening and thus it 
>> can also be removed from the
>> Reconfigure.)
>>
>> I think the text should be cleaned up to indicate that allowing 
>> removal of already reconfigured clients is recommended (to prevent 
>> unnecessary
>> reconfigures) when retransmitting the Reconfigure-Request.
>>
>> Note that if clients are added, that is not a retransmission but 
>> requires a "new" message (new XID).
>>
>> - Bernie
>>
>> -----Original Message-----
>> From: [e-mail] [mailto:[e-mail]] On 
>> Behalf Of Robert Sparks
>> Sent: Friday, April 26, 2013 12:19 PM
>> To: [e-mail]
>> Cc: [e-mail]; General Area Review Team; [e-mail]; 
>> draft-ietf- [e-mail]
>> Subject: Re: [dhcwg] RE : Gen-art review: draft-ietf-dhc-triggered-
>> reconfigure-05
>>
>> On 4/26/13 10:58 AM, [e-mail] wrote:
>>> Dear Robert,
>>>
>>> Thank you for the review.
>>> Please see inline.
>>>
>>> Cheers,
>>> Med
>>> ________________________________________
>>> De : [e-mail] [[e-mail]] de la part de 
>>> Robert Sparks [[e-mail]] Date d'envoi : vendredi 26 
>>> avril
>>> 2013 17:42 À : [e-mail]; [e-mail]; General Area Review 
>>> Team; [e-mail]
>>> Objet : [dhcwg] Gen-art review:
>>> draft-ietf-dhc-triggered-reconfigure-05
>>>
>>> I am the assigned Gen-ART reviewer for this draft. For background on 
>>> Gen-ART, please see the FAQ at
>>>
>>>
>> <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq><http://wiki
>> .tools .ietf.org/area/gen/trac/wiki/GenArtfaq>.
>>> Please resolve these comments along with any other Last Call 
>>> comments you may receive.
>>>
>>> Document: draft-ietf-dhc-triggered-reconfigure-05
>>> Reviewer:  Robert Sparks
>>> Review Date: April 26, 2013
>>> IETF LC End Date: May 6, 2013
>>> IESG Telechat date: May 16, 2013
>>>
>>> Summary: This draft is on the right track but has open issues, 
>>> described
>> in
>>>         the review.
>>>
>>> Major issues:
>>>
>>> Overall, this document is solid, but I think there is a bug in 
>>> section
>> 6.3.
>>> I could be wrong, but If I'm right, this paragraph:
>>>
>>> When retransmission is required, the relay may decide to correct the
>> content of RECONFIGURE-REQUEST message it issues (e.g., update the 
>> Client Identifier list).  This decision is local to the relay (e.g., 
>> it may be based on observed events such as one or more clients were 
>> reconfigured on their own).
>>> introduces a race-condition that could lead to an erroneous state. 
>>> If a
>> relay's first message included client A, then the retransmission 
>> included clients A and B, but that retransmission crosses with a 
>> success RECONFIGURE-REPLY to the request that only included client A, 
>> the relay will think it succeeded in asking A and B to be reconfigured.
>>> Med: This example does not apply for that text.
>> Really? What text constrains how you change what's in the retransmission?
>>>    In fact, the example should be the other way around. Perhaps, 
>>> this can
>> be made clearer if we change "(e.g., update the Client Identifier 
>> list)" to "(e.g., remove a client from the Client Identifier list)".
>> If I understand you correctly, you need more than just changing a 
>> parenthetical e.g.. I think you're saying that you are constraining 
>> the message changes to be such that if anything earlier in the 
>> retransmission sequence succeeded, the request in the retransmission 
>> would also have succeeded. But why do you need that much complexity? 
>> Do you have it already with any other request?
>>> Minor issues:
>>>
>>> This sentence:
>>>
>>> Furthermore, means to recover state in failure events must be 
>>> supported,
>> but are not discussed in this document.
>>> places a requirement on a relay (even though it's not using a 2119 MUST).
>> Is there some other document that defines this requirement that you 
>> can reference?
>>> Med: I'm not aware of any; but if there is one we can cite it.
>>>
>>>    If not, the requirement should be discussed in this document.
>> Alternatively, you could change the sentence to talk about the 
>> consequences of not having a proprietary means for recovering state.
>>> Med: Will consider that option if you think this is really needed.
>>>
>>> Nits/editorial comments:
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