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

[Volker Hilt <[e-mail]>]

I think SHOULD would, in fact, be the more appropriate wording here. 
There may be reasons why a local policy cannot be kept: a conflict with 
another policy, legal requirements, or very high levels of overload.

In the end, the local policy will be a local matter including its 
enforcement. In other words, if a service provider has a SIP server that 
ignores his policies, I'm sure the service provide will know who to call.

I've added a short explanatory sentence to the first paragraph:

A SIP client SHOULD 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 is expected generally to 
honor local policy except for very rare occasions when, for example, 
overload is so severe that messages, which should be preserved according 
to local policy, need to be discarded or local policies are in conflict.

A SIP client SHOULD 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 SHOULD honor the local policy for prioritizing SIP requests 
relating to emergency calls, as identified by the SOS URN [RFC5031] 
indicating an emergency request.

Thanks,

Volker [as individual]




On 14.01.2013 13:56, Salvatore Loreto wrote:
> my reading of the mailing list is that the question of using SHOULD
> versus MUST
> is being decided in favor of MUST
>
> however it would be great to also address the Valker concerns
> inserting a caveat/constraints explaining that the local policy can not
> override the overload mechanism/algorithm
>
> can someone propose text ?
>
> note this is the only remaining issue that we have to address in this
> event-package draft
> before we can ship to the IESG
>
> /Salvatore
>
>
> On 1/11/13 4:25 PM, Janet P Gunn wrote:
>>
>> Good point
>>
>> If you say it MUST honor "local policy", then you  need  constraints
>> on what the local policy can do (e.g., it can only prioritize within
>> the number of messages permitted by the overload algorithm, it can't
>> over ride the overload mechanism/algorithm)
>>
>> Janet
>>
>>
>>
>> [e-mail] wrote on 01/11/2013 09:06:58 AM:
>>
>> > From: Volker Hilt <[e-mail]>
>> > To: <[e-mail]>
>> > Date: 01/11/2013 09:07 AM
>> > Subject: Re: [sip-overload] Local Policy Re: I-D Action: draft-ietf-
>> > soc-load-control-event-package-05.txt
>> > Sent by: [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
>> > >
>> > > This is a PRIVATE message. If you are not the intended recipient,
>> please
>> > > delete without copying and kindly advise us by e-mail of the
>> mistake in
>> > > delivery. NOTE: Regardless of content, this e-mail shall not
>> operate to
>> > > bind CSC to any order or other contract unless pursuant to explicit
>> > > written agreement or government initiative expressly permitting
>> the use
>> > > of e-mail for such purpose.
>> > >
>> > >
>> > >
>> > > 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/
>> > >
>> > >
>> > >
>> > > _______________________________________________
>> > > sip-overload mailing list
>> > > [e-mail]
>> > > https://www.ietf.org/mailman/listinfo/sip-overload
>> > >
>> > _______________________________________________
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>>
>>
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>
>
> --
> Salvatore Loreto, PhD
> www.sloreto.com
>
>
>
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