Re: [Dime] [dime] #45: Why is a validity duration of 0 disallowed?

[Steve Donovan <[e-mail]>]

I think the proposal here is the following:

A reporting node communicates that an overload report is no longer valid
by sending an OLR with a Validity-Period AVP with a value of zero.  This
is the only way for a reporting node to indicate that an overload report
is no longer valid.  For instance, setting the reduction-percentage to
zero does not make the overload report invalid. 

Do we have agreement on this?

Steve

On 2/17/14 12:44 PM, Ben Campbell wrote:
> On Feb 17, 2014, at 12:08 PM, [e-mail] wrote:
>
>> I would like to highlight that my proposal is not related to the default Reduction-percentage algo.
>>
>> Whatever the ago used, I think that an OLR can only be sent for two purposes:
>> - Send an indication of overload situation
>> - Send an indication of end of the overload situation
>>
>> For me, providing both indications in the same message would be a non-sense. And I don't understand why the validity period would prevail in that case.
> So here's the question: Let's assume a reporting node sends you an OLR using the "loss" algorithm, a reduction-percentage of 50%, and a Validity-Duration of 10 minutes. 5 minutes later, it sends you a new OLR with an invalid reduction percentage and a Validity-Duration of 0.
>
> What's the current overload state?
>
> What if the second OLR used the "rate" algorithm, with a valid value, but still had a validity duration of 0. Does that change anything?
>
> I am arguing that, in both cases, the second OLR ends the overload period.
>
> I'm actually okay if we have a normative statement to the effect that the reporting node MUST NOT send an invalid reduction percentage, and that a reacting node MUST ignore an OLR with an invalid value _except_ for the case of a validity-duration set to zero.
>
> This all comes down to how much guessing we are willing to do about the intent of the sender when one receives an invalid OLR. I think it's reasonable to guess that a zero validity duration means to end an overload condition, without regard to the rest of the message. I _don't_ think it's reasonable to try to guess what the sender meant with an invalid reduction percentage, when the validity period is non-zero.
>
> Another, perhaps simpler, approach would be to assert that the reception of _any_ invalid OLR automatically ends any existing overload condition. (I'm not necessarily arguing for that--it's just something to think about.)
>
>> Now, if what is argued by Ben and supported by JJ and Steve is clear for the rest of the group, I will not fight.
> ... but the fighting is the fun part :-)
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