Re: [storm] MPA Draft - Review

arkady kanevsky <arkady.kanevsky@gmail.com> Tue, 05 April 2011 01:48 UTC

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Date: Mon, 4 Apr 2011 21:50:10 -0400
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From: arkady kanevsky <arkady.kanevsky@gmail.com>
To: Steve Wise <swise@opengridcomputing.com>
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Subject: Re: [storm] MPA Draft - Review
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Got it. Thanks Steve.
How about now?
Arkady

On Mon, Apr 4, 2011 at 9:41 PM, Steve Wise <swise@opengridcomputing.com>wrote;wrote:

>  The key word to remove here is "responder".  The IRD in the MPA start
> request is the initiators desired IRD _of the initiator_.  Not the
> initiators desired _responder_ IRD.
>
> If you want to change "desiired" to "initial" thats ok with me.  But the
> key is to get rid of the word "responder" in that sentence.
>
> Steve.
>
>
> On 4/4/2011 6:26 PM, arkady kanevsky wrote:
>
> Steve and Bob,
> I changed it to
> "In request: the Initiator desired responder IRD
> for the connection." as you asked.
> I can change it to "initial" instead of "desired".
> Arkady
>
> On Sun, Apr 3, 2011 at 5:36 PM, Steve Wise <swise@opengridcomputing.com>wrote;wrote:
>
>>  Hey Arkady,
>>
>> It does seem like you did the section 9 changes Bob and I requested:
>>
>> ----
>>
>>   Change the IRD definition on the request from "In request: the Initiator
>> requested responder IRD for the
>>   connection." to "In request: the Initiator initial IRD setting for the
>> connection."
>>  ----
>>
>> Thanks,
>>
>> Steve.
>>
>>
>> On 4/2/2011 8:35 PM, arkady kanevsky wrote:
>>
>> All,
>> updated version 04 is attached.
>>
>> Hemal,
>> Thanks for catching it.
>> I had fixed the first issue. I had added reference to FPDU in the FULPDU
>> definition for the second.
>>
>> David,
>> Please, check to see that you comments are addressed.
>>
>> Steve and Robert,
>> please, check that you comment is fixed correctly.
>>
>> Once I get positive feedback from all of you, I will submit the version.
>>
>> Thanks,
>> Arkady
>>
>> On Thu, Mar 31, 2011 at 2:43 PM, Hemal Shah <hemal@broadcom.com> wrote:
>>
>>>  I have some comments on -03 draft:
>>>
>>>
>>>    1. In section 10, it is written that "Enhanced MPA Initiator and
>>>    Responder:  If a responder receives an enhanced MPA message, it MUST respond
>>>    with an unenhanced MPA message." I think it should be written that the
>>>    responder must respond with an enhanced MPA message. It appears like a typo
>>>    to me.
>>>    2. I find the use of FULPDU confusing in this draft. RFC5044 does not
>>>    define term FULPDU. RFC5044 uses term FPDU to refer to Framed Protocol Data
>>>    Unit. I suggest that we use term FPDU instead of FULPDU in the draft.
>>>
>>>
>>> Hemal
>>>
>>>  -----Original Message-----
>>> From: storm-bounces@ietf.org [mailto:storm-bounces@ietf.org<storm-bounces@ietf.org>]
>>> On Behalf Of david.black@emc.com
>>> Sent: Thursday, March 31, 2011 7:48 AM
>>> To: storm@ietf.org
>>> Subject: Re: [storm] MPA Draft - Review
>>>  Importance: High
>>>
>>> The -03 version of the MPA draft has addressed all of the issues from my
>>> review, and .  Unfortunately, I need some minor edits for clarity before I
>>> can send this on to our AD with a publication request.  Would the authors
>>> please submit a -04 version with the following two changes quickly.
>>>
>>> Section 9 (end)
>>>
>>> OLD
>>>
>>>    The peer-to-peer negotiation for the RTR message follows the
>>>    following order:
>>>
>>>    Initiator -->: Sets Control Flags it is capable to send for RTR
>>>
>>>    Responder <--: Sets Control Flags it is capable to receive for RTR
>>>
>>>    Initiator -->: The first message send MUST be a negotiated RTR
>>>
>>> NEW
>>>
>>>    The peer-to-peer negotiation for the RTR message follows the
>>>    following order:
>>>
>>>    Initiator -->: Sets Control Flags to indicate Initiator-supported
>>> forms of RTR
>>>
>>>    Responder <--: Sets Control Flags to indicate Responder-supported
>>> forms of RTR
>>>
>>>    Initiator -->: If at least one form of RTR is supported by both
>>> Initiator and
>>>         Responder, then the first message sent MUST be an RTR using a
>>> form supported
>>>         by both the Initiator and Responder.
>>>
>>> Section 10
>>>
>>> OLD
>>>       In
>>>       this case initiator CAN attempt to establish RDMA connection using
>>>       unenhanced MPA protocol as defined in [RFC5044] and let ULP deal
>>>       with ORD and IRD, and peer-to-peer negotiations.
>>>
>>> NEW
>>>
>>>       In
>>>       this case initiator MAY attempt to establish RDMA connection using
>>> ------------------------->^^^
>>>       unenhanced MPA protocol as defined in [RFC5044] if this protocol is
>>>         compatible with the application, and let ULP deal with ORD and
>>> IRD,
>>>       and peer-to-peer negotiations.
>>>
>>> Ordinarily, I'd write an RFC Editor Note for small changes like these,
>>> but they're sufficiently critical to interoperability that I'd prefer to
>>> have a new draft version that contains them.
>>>
>>> Thanks,
>>> --David
>>>
>>>
>>> > -----Original Message-----
>>> > From: Black, David
>>> > Sent: Wednesday, December 22, 2010 9:26 PM
>>> > To: storm@ietf.org
>>> > Cc: Black, David
>>> > Subject: MPA Draft - Review
>>> >
>>> > WG Last Call on this draft has run its course:
>>> >
>>> >                  Enhanced RDMA Connection Establishment
>>> >                   draft-ietf-storm-mpa-peer-connect-02
>>> >
>>> > I've done my review as a WG chair (and the person who will be
>>> shepherding this draft to the ADs and
>>> > IESG):
>>> >
>>> > - This draft is on the right track, but has open issues.
>>> > - Another version of the draft will be needed.
>>> >
>>> > Also, it would be greatly appreciated if a few people other than the
>>> authors could take a look at
>>> > this draft.  We have a very good author team on this draft, whose
>>> expertise is beyond doubt, but
>>> > more eyes on this draft would help.
>>> >
>>> > [1] My primary concern is that Section 9 on interoperability is
>>> inadequate:
>>> >
>>> >    An initiator SHOULD NOT use the Enhanced DDP Connection
>>> Establishment
>>> >    formats or function codes when no enhanced functionality is desired.
>>> >
>>> >    A responder SHOULD continue to accept the unenhanced connection
>>> >    requests.
>>> >
>>> > The good news is that the first sentence is ok.
>>> > The bad news is that the second sentence has significant problems:
>>> >        - It uses SHOULD instead of MUST.
>>> >        - It doesn't lay out behavior for initiator and responder
>>> >                Revision mixes.
>>> > IETF interoperability requirements are usually expressed with MUST,
>>> including backwards
>>> > compatibility.  If interop with unenhanced implementations is only a
>>> SHOULD, that will need a
>>> > convincing explanation.
>>> >
>>> > There are 3 Initiator/Responder cases that need attention (New/Old,
>>> Old/New and New/New).  I think
>>> > they lead to roughly the following:
>>> >
>>> > New/Old:
>>> > - Explain error or failure that the New Initiator will see because the
>>> Old responder
>>> >        doesn't support Revision 2 of the MPA protocol.
>>> > - Explain what the Initiator does when it sees that error or failure.
>>> The
>>> >        easiest approach is to always retry with Revision 1, but that
>>> won't work
>>> >        if the Initiator has to send an RTR (that's the "convincing
>>> explanation"
>>> >        for why backwards compatibility is not always possible).  The
>>> result
>>> >        might be two requirements:
>>> >        - If the Initiator has data to send, it MUST retry with Revision
>>> 1.
>>> >        - If the Initiator has no data to send, and hence has to send an
>>> RTR,
>>> >                the connection setup fails, the TCP connection closes
>>> and that
>>> >                failure MUST to be reported to the application.
>>> >
>>> > Old/New:
>>> > - If a responder receives a Revision 1 message, it MUST respond with a
>>> Revision 1 message.
>>> >
>>> > New/New:
>>> > - If a responder receives a Revision 2 message, it MUST respond with a
>>> Revision 2 message.
>>> >
>>> > I found a few other concerns:
>>> >
>>> > [B]In Section 7, we need to get the listing of all the SCTP function
>>> codes into one place.  Either
>>> > repeat the definitions of codes 1-4 from RFC 5043, or create an IANA
>>> registry in Section 10 and list
>>> > all 7 codes as its initial contents.
>>> >
>>> > [C] In Section 8, what happens if the responder sends an IRD or ORD
>>> value that's different from the
>>> > corresponding initiator value?  Is the responder allowed to increase
>>> the value that was sent?  An
>>> > important case to cover is that the initiator sends a valid value
>>> (e.g., 0x2000) but the responder
>>> > returns the 0x3FFF value indicating that negotiation is not supported.
>>> Also, what is the behavior
>>> > of an IRD or ORD that is set to 0x0000?
>>> >
>>> > [D] In contrast, the Section 8 discussion of Control Flag functionality
>>> is in better shape.  It
>>> > would be helpful to add a sentence or two indicating when the RTR
>>> occurs (Request ->, <- Reply, RTR
>>> > ->), even though that is discussed earlier in the draft.  Also, it's
>>> necessary to state whether
>>> > negotiation of RTR functionality commits the Initiator to using an RTR
>>> (e.g., suppose the initiator
>>> > negotiates control flags to allow an RTR and instead sends an FULPDU
>>> with payload data after
>>> > receiving the Reply - is that ok or is it an error?).
>>> >
>>> > [E] Nit: In the definition of Control Flag A: ULPDU -> FULPDU
>>> >
>>> > Thanks,
>>> > --David
>>> > ----------------------------------------------------
>>> > David L. Black, Distinguished Engineer
>>> > EMC Corporation, 176 South St., Hopkinton, MA  01748
>>> > +1 (508) 293-7953             FAX: +1 (508) 293-7786
>>> > david.black@emc.com        Mobile: +1 (978) 394-7754
>>> > ----------------------------------------------------
>>>
>>> _______________________________________________
>>> storm mailing list
>>> storm@ietf.org
>>> https://www.ietf.org/mailman/listinfo/storm
>>>
>>>
>>>
>>> _______________________________________________
>>> storm mailing list
>>> storm@ietf.org
>>> https://www.ietf.org/mailman/listinfo/storm
>>>
>>>
>>
>>
>> --
>> Cheers,
>> Arkady Kanevsky
>>
>>
>> _______________________________________________
>> storm mailing liststorm@ietf.orghttps://www.ietf.org/mailman/listinfo/storm
>>
>>
>>
>
>
> --
> Cheers,
> Arkady Kanevsky
>
>
>


-- 
Cheers,
Arkady Kanevsky