Note that we could eliminate the text in this doc and rely on the relevant regulations to force devices to use the parameter. As long as the protocol can carry the value, then the regs can control what the device must do.
I suspect the concern about not understanding a value is probably covered by the same solution. If the device is licensed for a particular regulatory domain, then it will have to be able to handle all the values defined for that domain. The protocol needs a statement to cover it however. The usual advice is “ignore it”. Brian On Mar 6, 2014, at 5:18 AM, Andy Lee <[email protected]<mailto:[email protected]>> wrote: Thank you both for the additional clarifications. I think this is getting out-of-scope for the PAWS standard, but there is no future-proofing guidance here either. If a device built today knows what to do when etsiEnSimultaneousChannelOperationRestriction="0" and when etsiEnSimultaneousChannelOperationRestriction="1", what should it do when a database sends a value it doesn't recognize in the future? The spec is clear about what to do when the parameter is not sent at all, but no fallback behavior is defined for when the parameter takes on new values never seen before. This seems to be clearly out-of-scope of PAWS itself, and as Ben suggested, this should defer to the ETSI spec for details. However, this still leaves the question of what "must not ignore" means. Devices cannot process unknown future values, so how can they possibly "not ignore" a field that is unrecognizable to them? At this point, I think all we can say is that if a device encounters etsiEnSimultaneousChannelOperationRestriction="1", it must follow the ETSI power constraint rules. Any other statements about defaulting to "0" and "must not ignore" seem superfluous. Andy Lee | Google Inc. | [email protected]<mailto:[email protected]> | 408-230-0522 On Wed, Mar 5, 2014 at 7:26 PM, Benjamin A. Rolfe <[email protected]<mailto:[email protected]>> wrote: Thanks Vincent. I was attempting to capture what you just explained. I think that is what I captured - reference the ETSI spec for what to do when the value is not zero. I had guessed that the intent of adding this param was to provide a way to signal that an additional constraint is applied to the channels being used. On 3/5/2014 6:50 PM, Vincent Chen wrote: Ben, Andy, >From what I understood, the request is to add a parameter to the protocol with numeric string values, with a default value of "0". It does not limit the valid values to "0" or "1", and does not associate meaning to the values. The device behavior, upon receipt of the value, is defined by the ETSI specs, not the protocol doc. The "MUST NOT ignore" is intended to indicate that the device must understand the value, if present. The risk of not processing the value is that, if ETSI were to add another value that is more restrictive, the hard-coded device would be out of compliance. I believe the intent is to prevent hard-coding in devices. -vince On Wed, Mar 5, 2014 at 6:34 PM, Benjamin A. Rolfe <[email protected]<mailto:[email protected]>> wrote: I too was struggling with this wording. "Must not" is often problematic for me, and I was struggling to figure out how we verify that device has not ignored a parameter when the value of the paramter has a value that produces no observable behavior, such as the case Andy sites or the case where the value is zero. The logic should be: If (etsiEnSimultaneousChannelOperationRestriction == 0) Do what you were going to do anyway; else if (etsiEnSimultaneousChannelOperationRestriction == 1) Do not exceed the lower limit; The first condition looks to me pretty much the definition of "ignore" (based on my experience as a parent :-). Only the second condition can produce an observable change in the devices behavior. So if I have figured it out correctly the requirement being stated is: If the etsiEnSimultaneousChannelOperationRestriction paramter is provided and the value is 1, the Device MUST comply with the additional power restrictions when simultaneous transmission on multiple channel operation defined in [reference]. Is that right? -Ben On 3/5/2014 4:17 PM, Andy Lee wrote: I have a question about the new parameter etsiEnSimultaneousChannelOperationRestriction and the phrase "If it is provided, the Device MUST NOT ignore it." I can understand that if this parameter is provided and is set to "1", that the device must honor it (reduce output power when using multiple channels). But what if there is a device that "hard coded" to always apply the power restriction when using multiple channels? This "conservative" approach would always remain below the permitted emission limits regardless of whether this flag is set to "1" or "0". Are we saying that if this parameter is provided and is set to "0" that the device must not apply the multi-channel power restrictions? What does it mean to say "MUST NOT ignore it" in such a case. Andy Lee | Google Inc. | [email protected]<mailto:[email protected]> | 408-230-0522<tel:408-230-0522> On Wed, Mar 5, 2014 at 7:17 AM, Vincent Chen <[email protected]<mailto:[email protected]>> wrote: PAWS, Draft 11 contains the following changes: - Separation of protocol and regulatory requirements. In essence, MAY, MUST , SHOULD has been replaced where the text describes regulatory requirements and device behavior. They are replaced with just explanatory text. - Added the new ETSI parameter for simultaneous channel-operation restrictions Diff: http://www.ietf.org/rfcdiff?url1=draft-ietf-paws-protocol-10&difftype=--html&submit=Go%21&url2=draft-ietf-paws-protocol-11 -vince On Wed, Mar 5, 2014 at 7:09 AM, <[email protected]<mailto:[email protected]>> wrote: A New Internet-Draft is available from the on-line Internet-Drafts directories. This draft is a work item of the Protocol to Access WS database Working Group of the IETF. Title : Protocol to Access White-Space (PAWS) Databases Authors : Vincent Chen Subir Das Lei Zhu John Malyar Peter J. McCann Filename : draft-ietf-paws-protocol-11.txt Pages : 108 Date : 2014-03-05 Abstract: Portions of the radio spectrum that are allocated to licensees are available for non-interfering use. This available spectrum is called "White Space." Allowing secondary users access to available spectrum "unlocks" existing spectrum to maximize its utilization and to provide opportunities for innovation, resulting in greater overall spectrum utilization. One approach to manage spectrum sharing uses databases to report spectrum availability to devices. To achieve interoperability among multiple devices and databases, a standardized protocol must be defined and implemented. This document defines such a protocol, the "Protocol to Access White Space (PAWS) Databases". The IETF datatracker status page for this draft is: https://datatracker.ietf.org/doc/draft-ietf-paws-protocol/ There's also a htmlized version available at: http://tools.ietf.org/html/draft-ietf-paws-protocol-11 A diff from the previous version is available at: http://www.ietf.org/rfcdiff?url2=draft-ietf-paws-protocol-11 Please note that it may take a couple of minutes from the time of submission until the htmlized version and diff are available at tools.ietf.org<http://tools.ietf.org/>. Internet-Drafts are also available by anonymous FTP at: ftp://ftp.ietf.org/internet-drafts/ _______________________________________________ paws mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/paws -- -vince _______________________________________________ paws mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/paws _______________________________________________ paws mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/paws _______________________________________________ paws mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/paws -- -vince _______________________________________________ paws mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/paws _______________________________________________ paws mailing list [email protected]<mailto:[email protected]> https://www.ietf.org/mailman/listinfo/paws
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