Re: [sip-overload] Local Policy Re: I-D Action: draft-ietf-soc-load-control-event-package-05.txt

[Volker Hilt <[e-mail]>]

Janet, All,

while this sounds good in most cases, the concern I have is that there 
may be situation where a proxy is forced to violate local policy. E.g., 
a policy "emergency calls can never be dropped" will have to be violated 
eventually if overload reaches levels where only emergency calls are left.

Maybe this boils down to formulating policies in a reasonable way. It 
has to be made clear, however, that not all policies call be kept under 
all circumstances.

A SHOULD would imply this to the developer. With a MUST, I think one 
would have to add explanatory text.

Thanks,

Volker [with individual contributor hat on]



On 03.01.2013 18:52, Janet P Gunn wrote:
> I prefer MUST to SHOULD.
>
> The original wording was based on Req 13 of RFC 5390:
> " REQ 13:  The mechanism must not dictate a specific algorithm for
>        prioritizing the processing of work within a proxy during times of
>        overload*.  It must permit a proxy to prioritize requests based on*
> *      any local policy*, so that certain ones (such as a call for
>        emergency services or a call with a specific value of the
>        Resource-Priority header field [RFC4412]) are given preferential
>        treatment, such as not being dropped, being given additional
>        retransmission, or being processed ahead of others."
>
> which has a lower case "must".
>
> If we are going to say "MUST honor" (rather than "must permit"), I think
> we need to change "any" to "the" . (you can permit many alternatives,
> but you can really only honor one).  I think this also reflects the
> intent of Martin's  comment
>
> So I would prefer
>
>
>    A SIP client MUST honor *the *local policy for prioritizing SIP
>    requests such as policies based on message type, e.g., INVITEs vs.
>    requests associated with existing sessions.
>
>    A SIP client MUST honor *the *local policy for prioritizing SIP
>    requests based on the content of the Resource-Priority header (RPH,
>    RFC4412 [RFC4412]).  Specific (namespace.value) RPH contents may
>    indicate high priority requests that should be preserved as much as
>    possible during overload.  The RPH contents can also indicate a
>    low-priority request that is eligible to be dropped during times of
>    overload.
>
>    A SIP client MUST honor *the *local policy for prioritizing SIP
>    requests relating to emergency calls, as identified by the SOS
>    URN [RFC5031] indicating an emergency request.
>
>
> Thanks
>
> Janet
>
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>
> From: "Vijay K. Gurbani" <[e-mail]>
> To: Charles Shen <[e-mail]>
> Cc: "DRAGE, Keith (Keith)" <[e-mail]>om>, Janet P
> Gunn/USA/CSC@CSC, "[e-mail]" <[e-mail]>rg>, Arata
> Koike <[e-mail]>jp>, "NOEL, ERIC (ERIC C)"
> <[e-mail]>om>, Henning Schulzrinne <[e-mail]>
> Date: 01/03/2013 11:42 AM
> Subject: Re: [sip-overload] Local Policy Re: I-D Action:
> draft-ietf-soc-load-control-event-package-05.txt
> ------------------------------------------------------------------------
>
>
>
> On 01/03/2013 07:34 AM, Charles Shen wrote:
>  > Sounds good, I can update the wording in the event package draft, if
>  > Vijay is OK with the other one.
>
> I just want to make sure we are all agreeing to the same thing.
>
> It seems to me that the question of using SHOULD versus MUST is being
> decided slightly in favour of a MUST.  Martin and Bruno prefer a MUST,
> Janet is okay with, although her original text used a SHOULD; and Keith
> could go either way.
>
> Is the consensus, then, that the text on honoring local policy contains
> MUST?  If so, the text to be inserted would be the following:
>
>    A SIP client MUST honor any local policy for prioritizing SIP
>    requests such as policies based on message type, e.g., INVITEs vs.
>    requests associated with existing sessions.
>
>    A SIP client MUST honor any local policy for prioritizing SIP
>    requests based on the content of the Resource-Priority header (RPH,
>    RFC4412 [RFC4412]).  Specific (namespace.value) RPH contents may
>    indicate high priority requests that should be preserved as much as
>    possible during overload.  The RPH contents can also indicate a
>    low-priority request that is eligible to be dropped during times of
>    overload.
>
>    A SIP client MUST honor any local policy for prioritizing SIP
>    requests relating to emergency calls, as identified by the SOS
>    URN [RFC5031] indicating an emergency request.
>
> Yes?
>
> Thanks,
>
> - vijay
> --
> Vijay K. Gurbani, Bell Laboratories, Alcatel-Lucent
> 1960 Lucent Lane, Rm. 9C-533, Naperville, Illinois 60563 (USA)
> Email: vkg@{bell-labs.com,acm.org} / [e-mail]
> Web: http://ect.bell-labs.com/who/vkg/
>
>
>
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