Re: [sip-overload] WGLC: draft-ietf-soc-overload-rate-control - Christer's comments

[Paul Kyzivat <[e-mail]>]

Sorry, I haven't been following the progress of this draft for a long 
time, but this just caught my eye...

The ABNF of 3261 is no longer authoritative for header field parameters. 
This was changed by RFC3968. Now these are registered in the "Header 
Field Parameters and Parameter Values" sub-registry of the IANA "Session 
Initiation Protocol (SIP) Parameters" registry.

So you need an IANA considerations section that provides the info in the 
form called out in Section 4.1 of RFC3968.

There is some debate if need, or even if it is good to provide ABNF 
extension syntax relative to 3261. IMO it is sufficient for you to 
register the parameter in IANA and define the syntax of the parameter 
*value* using ABNF.

Done that way, IMO the draft doesn't technically extend 3261, but that 
point has also been debated.

If you want to reuse EQUAL and DIGIT from 3261 then you should probably 
say so, though if you are formally extending 3261 via =/ then of course 
you are implicitly inheriting everything defined in 3261.

	Thanks,
	Paul


On 6/28/13 2:32 AM, Christer Holmberg wrote:
> The following is obviously not needed in draft-ietf-soc-overload-control:
>
> "EQUAL" is defined in RFC 3261.  "DIGIT" is defined in RFC 5234.
>
> *From:*[e-mail]
> [mailto:[e-mail]] *On Behalf Of *Christer Holmberg
> *Sent:* 28. kesäkuuta 2013 9:27
> *To:* Janet P Gunn
> *Cc:* [e-mail];
> [e-mail];
> [e-mail]
> *Subject:* Re: [sip-overload] WGLC: draft-ietf-soc-overload-rate-control
> - Christer's comments
>
> Hi,
>
> So, with the third alternative, Section 5 would look something like:
>
> 5.  Syntax
>
>     This specification extends the existing definition of the Via header
>
>     field parameters of [RFC3261] as follows:
>
>          via-params =/ oc-nan
>
>         oc-nan      = "NaN"
>
> BTW, I think the syntax in *draft-ietf-soc-overload-control *should look
> like:
>
> ***via-params  =/ oc / oc-validity / oc-seq / oc-algo*
>
>         oc          = "oc" [EQUAL oc-num]
>
>         oc-num      = 1*DIGIT
>
>         oc-validity = "oc-validity" [EQUAL delta-ms]
>
>         oc-seq      = "oc-seq" EQUAL 1*12DIGIT "." 1*5DIGIT
>
>         oc-algo     = "oc-algo" EQUAL DQUOTE algo-list *(COMMA algo-list)
>
>                       DQUOTE
>
>         algo-list   = "loss" / *(other-algo)
>
>         other-algo  = %x41-5A / %x61-7A / %x30-39
>
>         delta-ms    = 1*DIGIT
>
> **
>
> In both drafts, I would also suggest to rewrite the Syntax sections in
> the following way:
>
> 5.  Grammar
>
> 5.1.  General
>
>     This section extends the ABNF definition of via-params from [RFC3261]
>
>     by adding a new Via header field parameter, "oc-nan".  The ABNF defined
>
>     in this specification is conformant to RFC 5234 [RFC5234].  "EQUAL"
>
>     is defined in RFC 3261.  "DIGIT" is defined in RFC 5234.
>
> 5.2.  ABNF
>
>     via-params =/ oc-nan
>
>     oc-nan      = "NaN"
>
> **
>
> Regards,
>
> Christer
>
> **
>
> **
>
> **
>
> *From:*Christer Holmberg
> *Sent:* 28. kesäkuuta 2013 8:40
> *To:* Christer Holmberg; Janet P Gunn
> *Cc:* [e-mail]
> <mailto:[e-mail]>;
> [e-mail]
> <mailto:[e-mail]>;
> [e-mail] <mailto:[e-mail]>
> *Subject:* VS: [sip-overload] WGLC: draft-ietf-soc-overload-rate-control
> - Christer's comments
>
> Hi,
>
> A *third alternative* (probably the easiest one, at least from a syntax
> perspective) would be to simply define a new “oc-nan” Via header field
> parameter.
>
> *oc-nan          = "nan"*
>
> …or something like that.
>
> It would *not* require any changes to draft-ietf-soc-overload-control .
>
> (Then, in the *procedure sections* you need to describe how/whether the
> oc and oc-nan parameters can be used at the same time etc, but that is
> not a syntax question.)
>
> Regards,
>
> Christer
>
> *Lähettäjä:*[e-mail]
> <mailto:[e-mail]>[mailto:[e-mail]]
> *Puolesta *Christer Holmberg
> *Lähetetty:* 27. kesäkuuta 2013 22:42
> *Vastaanottaja:* Janet P Gunn
> *Kopio:* [e-mail]
> <mailto:[e-mail]>;
> [e-mail]
> <mailto:[e-mail]>;
> [e-mail] <mailto:[e-mail]>
> *Aihe:* Re: [sip-overload] WGLC: draft-ietf-soc-overload-rate-control -
> Christer's comments
>
> Hi,
>
> When taking a closer look, I actually think there is something
> technically wrong with the syntax in Section 5 of
> draft-ietf-soc-overload-rate-control.
>
> *draft-ietf-soc-overload-control * defines the oc parameter as:
>
> *oc          = "oc" [EQUAL oc-num]*
>
> Now, it seems like *draft-ietf-soc-overload-rate-control* actually
> *re-defines *the *same parameter*. In addition, it’s done in a backward
> compatible manner, e.g. because the parameter can now contain a
> non-numeric value (see the bullet list below what can go wrong):
>
> *oc          = "oc" EQUAL oc-value*
>
> The following can happen:
>
> 1.If an entity that supports draft-ietf-soc-overload-control  receives
> *“oc=NaN”* it will *reject* it, as it expects a numeric value.
>
> 2.If an entity that supports draft-ietf-soc-overload-rate-control
> receives *“oc”* it will *reject* it, as it expects an oc-value. But, in
> draft-ietf-soc-overload-control  the usage of oc-value is optional.
>
> One way to fix this could be to define oc-value as a separate Via header
> field parameter (similar to oc-validity, oc-seq etc), instead of a value
> of the oc parameter. But, then you would have oc-num
>
> Another way is to change the syntax in draft-ietf-soc-overload-control ,
> in order to allow what you want to do in
> draft-ietf-soc-overload-rate-control.
>
> Regards,
>
> Christer
>
> *Lähettäjä:*Janet P Gunn [mailto:[e-mail]]
> *Lähetetty:* 27. kesäkuuta 2013 22:04
> *Vastaanottaja:* Christer Holmberg
> *Kopio:* [e-mail]
> <mailto:[e-mail]>;
> [e-mail] <mailto:[e-mail]>;
> [e-mail] <mailto:[e-mail]>
> *Aihe:* Re: VS: [sip-overload] WGLC:
> draft-ietf-soc-overload-rate-control - Christer's comments
>
> Christer
>
>   draft-ietf-soc-overload-control  says
> " 8.  Syntax
>
>     This specification extends the existing definition of the Via header
>     field parameters of [RFC3261] as follows:
>
>         via-params  =  via-ttl / via-maddr
>                        / via-received / via-branch
>                        / oc / oc-validity
>                        / oc-seq / oc-algo / via-extension
>
>
>         oc          = "oc" [EQUAL oc-num]
>         oc-num      = 1*DIGIT
>         oc-validity = "oc-validity" [EQUAL delta-ms]
>         oc-seq      = "oc-seq" EQUAL 1*12DIGIT "." 1*5DIGIT
>         oc-algo     = "oc-algo" EQUAL DQUOTE algo-list *(COMMA algo-list)
>                       DQUOTE
>         algo-list   = "loss" / *(other-algo)
>         other-algo  = %x41-5A / %x61-7A / %x30-39
>         delta-ms    = 1*DIGIT"
> and
> "11.  IANA Considerations
>
>     This specification defines four new Via header parameters as detailed
>     below in the "Header Field Parameter and Parameter Values" sub-
>     registry as per the registry created by [RFC3968].  The required
>     information is:
>
>         Header Field  Parameter Name  Predefined Values  Reference
>         __________________________________________________________
>         Via           oc                 Yes             RFCXXXX
>         Via           oc-validity        Yes             RFCXXXX
>         Via           oc-seq             Yes             RFCXXXX
>         Via           oc-algo            Yes             RFCXXXX
>
>         RFC XXXX [NOTE TO RFC-EDITOR: Please replace with final RFC
>         number of this specification.]"
>
> The text of draft-ietf-soc-overload-control refers to both "loss" and
> "rate"  as values for  oc-algo.
>
> The text of draft-ietf-soc-overload-control  section 5.3 refers to the
> use of oc for either rate or loss
>
> "As an example, a value of "oc=10" when the loss-based algorithm is
>     used implies that 10% of the total number of SIP requests (dialog
>     forming as well as in-dialogue) are subject to reduction at the
>     client.  Analogously, a value of "oc=10" when the rate-based
>     algorithm [I-D.ietf-soc-overload-rate-control] is used indicates that
>     the client should send SIP requests at a rate of 10 SIP requests or
>     fewer per second."
>
> What are you suggesting would go in the "IANA Considerations" section of
>   draft-ietf-soc-overload-rate-control ?  Does it just need a reference
> to the IANA Considerations in draft-ietf-soc-overload-control?
>
> Janet
>
>
>
>
>
>
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>
>
> From: Christer Holmberg <[e-mail]
> <mailto:[e-mail]>>
> To: Janet P Gunn/USA/CSC@CSC
> Cc: "[e-mail]
> <mailto:[e-mail]>"
> <[e-mail]
> <mailto:[e-mail]>>,
> "[e-mail] <mailto:[e-mail]>"
> <[e-mail] <mailto:[e-mail]>>,
> "[e-mail] <mailto:[e-mail]>"
> <[e-mail] <mailto:[e-mail]>>
> Date: 06/27/2013 12:54 PM
> Subject: VS: [sip-overload] WGLC: draft-ietf-soc-overload-rate-control -
>     Christer's comments
>
> ------------------------------------------------------------------------
>
>
>
>
> Hi,
>
>>The IANA considerations section of  draft-ietf-soc-overload-control
> registers the new Via header field parameters.
>>
>>Is it needed here as well?
>
> The draft (Section 5) does extend the oc parameter, doesn’t it? I would
> assume that needs to go to IANA.
>
> Regards,
>
> Christer
>
> _
> [e-mail]
> <mailto:[e-mail]>wrote on 06/27/2013 06:05:41 AM:
>
>> From: Christer Holmberg <[e-mail] <mailto:[e-mail]>>
>> To: "[e-mail] <mailto:[e-mail]>"
> <[e-mail] <mailto:[e-mail]>>
>> Cc: "[e-mail]
> <mailto:[e-mail]>"
>> <[e-mail]
> <mailto:[e-mail]>>
>> Date: 06/27/2013 06:05 AM
>> Subject: [sip-overload] WGLC: draft-ietf-soc-overload-rate-control -
>> Christer's comments
>> Sent by:[e-mail] <mailto:[e-mail]>
>>
>> Hi,
>>
>> I have read draft-ietf-soc-overload-rate-control-04.txt as part of the WGLC.
>>
> ...
>> Q7: In Section 7 you say that there are no IANA considerations. But,
>> don’t you need to request IANA to register the new Via header field
>> parameters?
>>
>> Regards,
>>
>> Christer
>>
>>
>>
>>
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