Re: [Dime] [dime] #31: Sending OC-Ongoing-Throttling-Info AVP in request messages that survived a throttling

["Wiehe, Ulrich (NSN - DE/Munich)" <[e-mail]>]

Actually we seem to agree on two principles:
1. Lack of OLR means "no change"
2. the reporting node (no matter whether overloaded or not) MAY decide not to return an OLR in response to requests which contained an OC-Supported-Feature AVP if it is aware that the reacting node already has got the latest OLR (which may be an OLR requesting traffic reduction or an OLR indicating "no overload"); otherwise (i.e. if it is not aware...) the reporting node (no matter whether overloaded or not) MUST return an OLR in responses to requests which contained an OC-Supported-Feature AVP.

Can people please confirm.

Ulrich

From: DiME [mailto:[e-mail]] On Behalf Of ext Steve Donovan
Sent: Wednesday, February 05, 2014 4:35 PM
To: Nirav Salot (nsalot); [e-mail]
Subject: Re: [Dime] [dime] #31: Sending OC-Ongoing-Throttling-Info AVP in request messages that survived a throttling

Agreed.  To restate -- lack of an overload report does not change the current overload state for the host or realm.  If there is a currently active overload report then it continues to apply until it either times out or is explicitly changed with a new overload report.  If there is no currently active overload report then lack of an overload report implies there is no overload for the host and realm.

Steve
On 2/5/14 9:19 AM, Nirav Salot (nsalot) wrote:
I agree with Steve except the part "shouldn’t lack of OLR be interpreted as not overloaded?"
 
We had some discussion sometime back and thought that it is reasonable to not mandate the server to include the OLR in every answer message. E.g. when the server is capable of tracking what is sent to which client and hence wants to avoid sending information which is redundant. But this is optional implementation and at the same time need not be prohibited from protocol point of view.
 
So basically, the lack of OLR should not affect the previously received OLR at the reacting node. The reacting node can continue to react based on older OLR until the expiry of the validity-period or when the explicit OLR with "0" overload-metric is received.
In my view, this allows for flexible implementation at the reporting node and sound handling of OLR at the reacting node.
 
Regards,
Nirav.
 
From: DiME [mailto:[e-mail]] On Behalf Of Steve Donovan
Sent: Wednesday, February 05, 2014 8:00 PM
To: [e-mail]
Subject: Re: [Dime] [dime] #31: Sending OC-Ongoing-Throttling-Info AVP in request messages that survived a throttling
 
inline
On 2/5/14 7:57 AM, Wiehe, Ulrich (NSN - DE/Munich) wrote:
Ok then let's state that reporting nodes MUST insert an OC-OLR AVP in all answer messages that correspond to request messages which contain an OC-Supported-Features AVP (even when no load reduction is requested).
SRD> Why in every answer message?  Shouldn't lack of an OLR be interpreted as not overloaded?


 
 
Other criteria like REQ18 or REQ13 do not seem to matter.
SRD> Requiring an overload report in every answer does directly break REQ13, but requiring an overloaded node to look for an OC-Ongoing-Throttling-Info AVP in every message is also substantial additional work, potentially more expensive than inserting OLRs.


 
 
For my clarification: I guess that the reacting node is not required to process every single OLR received (most will be replays anyway). What would be the procedure in the reacting node in order to minimize processing of replayed OLRs and at the same time minimize the risk too miss a new OLR?
SRD> That is the purpose of the sequence number.  


 
 
 
-----Original Message-----
From: DiME [mailto:[e-mail]] On Behalf Of ext Nirav Salot (nsalot)
Sent: Wednesday, February 05, 2014 5:27 AM
To: [e-mail]; [e-mail]
Subject: Re: [Dime] [dime] #31: Sending OC-Ongoing-Throttling-Info AVP in request messages that survived a throttling
 
I share the same opinion as Lionel.
 
Regards,
Nirav.
 
-----Original Message-----
From: DiME [mailto:[e-mail]] On Behalf Of [e-mail]
Sent: Tuesday, February 04, 2014 9:07 PM
To: [e-mail]
Subject: Re: [Dime] [dime] #31: Sending OC-Ongoing-Throttling-Info AVP in request messages that survived a throttling
 
I understand that the real concern is when the reporting node DOES NOT insert the OLR in every answer. 
So the options would be:
1- OC-OLR AVP in every answer
2- OC-Ongoing-Throttling-Info AVP in every request + OC-OLR AVP in some answer when the current throttling performed by the client needs to be updated.
 
If there is no other criterion, the option 1 seems the best approach.
 
Lionel
 
-----Message d'origine-----
De : dime issue tracker [mailto:[e-mail]]
Envoyé : mardi 4 février 2014 09:49
À : MORAND Lionel IMT/OLN
Cc : [e-mail]
Objet : [dime] #31: Sending OC-Ongoing-Throttling-Info AVP in request messages that survived a throttling
 
#31: Sending OC-Ongoing-Throttling-Info AVP in request messages that survived a throttling
 
 It has been proposed to define an OC-Ongoing-Throttling-Info AVP that is  to be included by the reacting DOIC endpoint in request messages that  survived a throttling. This AVP would indicate the Sequence-Number
 (TimeStamp) of the OLR according to which the throttling (which was
 survived) is performed. Absence of this AVP indicates that currently no  throttling is performed.  Reporting DOIC endpoints may use this  information in order to detect whether there is a need to update the  reacting DOIC endpoint with the latest OLR.
 Absence of this feedback mechanism would result in the need for the  reporting node to send OC-OLR AVPs in every answer as the reporting DOIC  endpoint cannot know whether the reacting DOIC endpoint is actually doing  the right thing with regard to throttling/not throttling.
 The feedback mechanism improves robustness as it allows the reporting DOIC  endpoint to detect and correct inappropriate throttling by the reacting  DOIC endpoint (caused by whatever reason).
 The feedback mechanism also allows to address REQ 18 from RFC 7068.
 In summary it is proposed to define the OC-Ongoing-Throttling-Info AVP to  be used in request messages that survived a throttling.