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

[Maria Cruz Bartolome <[e-mail]>]

Ben,

This approach sounds reasonable to me.
But I would like to clarify what should be the behavior if a Reduction-Percentage=0 is received. This is an invalid value, then I presume it should be discarded by client.

Regards
/MCruz

From: DiME [mailto:[e-mail]] On Behalf Of Ben Campbell
Sent: martes, 11 de febrero de 2014 0:56
To: Jouni Korhonen
Cc: [e-mail] list; [e-mail]
Subject: Re: [Dime] [dime] #45: Why is a validity duration of 0 disallowed?

So, here's some proposed text. (intentionally ignoring the related discussion about handling invalid values):

Section 4.5, first paragraph, last 2 sentences:

Old:

Validity duration values 0 (i.e., 0 seconds) and above 86400 (i.e., 24 hours) MUST NOT be used. Invalid validity duration values are treated as if the OC-Validity-Duration AVP were not present.

New:

Validity duration values above 86400 MUST NOT be used. Invalid validity duration values are treated as if the OC-Validity-Duration AVP were not present. A value of zero (0) indicates that an existing overload condition has ended and that the reporting node is in a stable condition.

Section 4.7, 2nd paragraph:

Old:

 The value of the Reduction-Percentage AVP is between one (1) and one hundred (100).  Values greater than 100 are interpreted as 100.  The value of 100 means that no traffic is expected, i.e. the reporting node is under a severe load and ceases to process any new messages. The Reduction-Percentage AVP MUST be present in an overload report that uses the default abatement algorithm.

Note that there is no zero (0) value defined for the Reduction-Percentage AVP. A zero value would logically indicate that no overload abatement is requested. Instead, reporting nodes use a OC-Validity-Duration AVP value of zero (0) to indicate the end of an overload condition. [Section 4.5]






On Feb 10, 2014, at 4:12 PM, Jouni Korhonen <[e-mail]<mailto:[e-mail]>> wrote:


Just post it here.



On Feb 10, 2014, at 6:25 PM, Ben Campbell <[e-mail]<mailto:[e-mail]>> wrote:


Okay. Does that mean we should assign the issue to me in the tracker?

On Feb 10, 2014, at 10:06 AM, Jouni Korhonen <[e-mail]<mailto:[e-mail]>> wrote:



Ben,

Propose some text and we can see how it fits in.

- Jouni


On Feb 10, 2014, at 5:53 PM, Ben Campbell <[e-mail]<mailto:[e-mail]>> wrote:



On Feb 10, 2014, at 5:12 AM, Jouni Korhonen <[e-mail]<mailto:[e-mail]>> wrote:



On Feb 7, 2014, at 11:54 PM, dime issue tracker <[e-mail]<mailto:[e-mail]>> wrote:


#45: Why is a validity duration of 0 disallowed?

Section 4.5 disallows a validity duration of zero. Why do we want to
disallow that? It would allow a quick way of ending any existing overload
condition without worrying about the semantics of the abatement algorithm.
(We currently use a reduction percentage of zero to end an overload
condition--but that's specific to the loss algorithm and might not make
sense for all future ones.)

Right. Avoiding two ways of ending overload condition was the reason.
I am OK to have validity duration 0 as an additional method ending the
overload condition based on the reasoning above.

I would go further and make duration 0 the _preferred_ way, for two reasons:

1) It's algorithm independent. (reduction-percentage of 0 is specific to algorithms that use reduction percentage.)

2) Explicit signaling of the end of an overload condition becomes semantically identical to the expiration of an overload condition. This allows a simpler implementation.




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