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

[Christer Holmberg <[e-mail]>]

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]; [e-mail]; [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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