Re: [Dime] Issue#35 conclusion

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

Hello all,

Not sure we all have the same understanding here.
Let me try to explain my concerns.

The original 3GPP requirement we want to cover is the need for a server to reduce traffic for one specific client, i.e. traffic identified by "Origin-Host" in the request.
Then, two options are under analysis about whether or not the OLR in the server answer shall be marked:

a) OLR does not need to include anything else
Receiver of the answer (and OLR) is the client that sends the request, identified by "Origin-Host" in the request.
Then, as long as the reacting node=="Origin-Host", the expected reduction is performed and requirement fulfilled.
But, when an agent is acting on behalf of a client as the reacting node, then the "Origin-Host" identifies final client, but not the reacting node.
Then, this is why the proposal is to add following clarification about agent behavior (possible clause 5.5):
"When an agent takes the role of a reacting node, the agent needs to bind a received OLR to the origin host of the client that initiated the request which corresponds to the answer containing the OLR."
But this will imply that _always_ the reacting node applies this OLR to one specific client, what is not what we need to achieve.
How will this impact the case where the agent is providing access to a Realm? E.g. C1 and C2 accesses RealmX (S1 + S2) via Agent1. Let's consider following example:
- C1 sends a Realm request via Agent, that finally reaches S1
- S1 answers with OLR (Host:50%).
- Agent is acting as reacting node on behalf of C1, if it considers this OLR only bind to C1... then... should it consider S1-OLR only as relevant for requests coming from C1? Should agent do not use this S1-OLR to calculate aggregated Realm overload?
In my opinion, in this case it does not make sense to consider OLR was only meant to C1. And this problem could be solved adding explicit information, as in b) below.

b) OLR needs to be extended (new AVP) that identifies the client ("Origin-Host" in the request) from which traffic reduction shall apply.
With this new AVP, reacting node will easy be able to identify when OLR shall be applied to any client or just to the Origin-Host identified by new AVP.

Let me know your opinions please
Best regards
/MCruz



-----Original Message-----
From: DiME [mailto:[e-mail]] On Behalf Of Wiehe, Ulrich (NSN - DE/Munich)
Sent: lunes, 24 de febrero de 2014 12:28
To: ext Steve Donovan; [e-mail]
Subject: Re: [Dime] Issue#35 conclusion

Steve,

please see inline.

Ulrich

From: DiME [mailto:[e-mail]] On Behalf Of ext Steve Donovan
Sent: Friday, February 21, 2014 4:53 PM
To: [e-mail]
Subject: Re: [Dime] Issue#35 conclusion

Ulrich,

I have a couple of concerns with this approach, as currently outlined.  

First, how do we handle the case where there are multiple DOIC supporting agents between the non supporting client and the reporting node.  This, I guess, is a general question, not just applying to this proposal.  I suggest we capture in the agent behavior section that is currently missing wording indicating that the first supporting agent that receives the request must be the reacting node for that non-supporting client.  Subsequent DOIC supporting agents must not be the reacting node for the non-supporting client.
<Ulrich>I fully agree</Ulrich>


We need to think through the ramifications of having multiple agents being the reacting node for the same non supporting clients, as this could easily happen in networks where multiple agents are involved in a single transaction.  On the surface it doesn't seem to be an issue for the loss algorithm, but this might not be the case with other algorithms.
<Ulrich>I agree that this is not an issue for loss; it is an issue e.g. for rate (i.e. for draft-donovan-dime-doc-rate-control)</Ulrich>

My other concern is that this puts a lot of extra onus on the agent even for the case where the reporting node does not want to differentiate overload reports.
<Ulrich> I agree </Ulrich>
To this end I suggest we add an indication in the OLR marking the reports that are specific to just the Origin-Host in the request.  Absence of the "single-client-only" AVP would mean that the report applies to all clients.  Presence of the AVP would indicate that the OLR applies to the Origin-Host.
<Ulrich>I understand that the proposal is an optimization for agents. Therefore the semantics of the marking should be reverse: unmarked OLRs are client specific, marked OLRs indicate that the reporting node does not want to differentiate, and therefore allow agents not to do the binding to the client.</Ulrich>     

Steve
On 2/21/14 4:48 AM, Wiehe, Ulrich (NSN - DE/Munich) wrote:
Ben,

the proposed conclusion was based on comments received so far (from Lionel, Nirav, Steve, MCruz, JJ). 
Now you seem to address two points:
a) There is no dependency to DOIC support of the client.
To address this I would like to propose rewording of the clarifying text for 5.5. as follows:

When an agent takes the role of a reacting node, the agent needs to bind a received OLR to the origin host of the client that initiated the request which corresponds to the answer containing the OLR. 

This would cover not only the case where an agent takes the role of the reacting node on behalf of a (or several) non supporting client, but also the case where an agent is configured to take the role of a reporting node (for realm-type reports) towards the client and at the same time the role of a reacting node towards the server.

b) There is no binding of the OLR to the orig-host of the client Here I disagree. We have the 3GPP requirement to allow requesting different amount of reduction from different clients, and I think we have 3 options:
1. ignore the 3GPP requirement
2. introduce new report types as originally proposed in #35 3. introduce the binding between OLR and orig-host of the client.

So far I understood that people favoured option 3.

See also inline.

Ulrich



-----Original Message-----
From: ext Ben Campbell [mailto:[e-mail]]
Sent: Thursday, February 20, 2014 11:55 PM
To: Wiehe, Ulrich (NSN - DE/Munich)
Cc: [e-mail]
Subject: Re: [Dime] Issue#35 conclusion


On Feb 20, 2014, at 6:41 AM, Wiehe, Ulrich (NSN - DE/Munich) <[e-mail]> wrote:

#35: additional report types are proposed
 
Dear all,
 
I believe we can conclude, not to add additional report types. However, we agreed to add clarifying text to clause 5.5 as follows:
 
When an agent received an OLR in response to a request initiated by a client not supporting DOIC, this agent needs to bind the received OLR to the origin-host of the client.

I do not agree.

You proposal implies that the server's OLR only applies to that client.
<Ulrich>exactly, that was the intention</Ulrich>
 If there's an intervening DOIC agent, then the agent, not the client, is the reacting node from the server's perspective.
<Ulrich> the server's perspective is agnostic. The server does not know whether it's the client or an agent on the path that takes the role of the reacting node</Ulrich>
 But, short of adding an origin-host type, nothing binds the OLR to a particular client, regardless of DOIC support at the clients.
<Ulrich> the binding is always there, regardless of DOIC support at the client</Ulrich>

 Whether or not the client also supports DOIC doesn't change that. For DOIC-supporting clients, the agent has the additional option of reducing traffic by asking the clients to reduce traffic (making them reacting nodes from the perspective of the _agent_, but not the server.)  It doesn't have that option for non-DOIC clients.

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