Re: [Dime] [dime] #57: Handling of "Realm-Routed" Overload report type

[Steve Donovan <[e-mail]>]

How do agents learn about a set of servers ability to handle new
sessions (host-less requests) if servers never sent realm-routed-request
reports?

I agree that agents should sent to aggregated report but the servers
need to send RRR reports so the agent can route around them and generate
those aggregated reports.

Steve

On 2/25/14 1:50 AM, Wiehe, Ulrich (NSN - DE/Munich) wrote:
>
> Hi,
>
> I agree with MCruz.
>
>  
>
> Principle is that the server never sends OLRs with a report type of
> realm-routed-request (exept the case where the server knows (i.e.is
> configured) that there is no other server in that realm).
>
>  
>
> Only agents that are configured to take the role of a reporting node
> for a realm will insert OLRs with report type of realm-routed-requests
> into answer messages and the content should be the aggregation of
> percentages as received in host type OLRs from all the servers in the
> realm.
>
>  
>
> Ulrich
>
>  
>
>  
>
>  
>
>  
>
> *From:*DiME [mailto:[e-mail]] *On Behalf Of *ext Steve
> Donovan
> *Sent:* Monday, February 24, 2014 8:31 PM
> *To:* Maria Cruz Bartolome; [e-mail];
> [e-mail]
> *Subject:* Re: [Dime] [dime] #57: Handling of "Realm-Routed" Overload
> report type
>
>  
>
> Maria Cruz,
>
> Thanks for the comments.  We obviously have a different understanding
> of the meaning of realm-routed-request report (new attempt at a name
> to try to make Ulrich happy :-) ).
>
> My definition is that it is a report generated by the server when the
> server does not want to receive new sessions. 
>
> Your definition appears to be that it is a report generated by an
> agent (or a server is there are no agents in the network?) to indicate
> that the network need to handle fewer new sessions.
>
> I actually think both cases apply but I don't think that an agent can
> generate a realm-routed-request report without knowing the status of
> servers and their ability to handle new Diameter sessions.
>
> Note that I'm discussing this in the context of session-based
> applications.  This could also be applied to pseudo session based
> applications and applications that always rely on realm routed requests.
>
> Everyone, which definition applies?
>
> Steve
>
> On 2/24/14 12:51 PM, Maria Cruz Bartolome wrote:
>
>     Steve,
>
>      
>
>     See some comments below please.
>
>     /MCruz
>
>      
>
>     -----Original Message-----
>
>     From: DiME [mailto:[e-mail]] On Behalf Of dime issue tracker
>
>     Sent: lunes, 24 de febrero de 2014 17:20
>
>     To: [e-mail] <mailto:[e-mail]>; [e-mail] <mailto:[e-mail]>
>
>     Cc: [e-mail] <mailto:[e-mail]>
>
>     Subject: [Dime] [dime] #57: Handling of "Realm-Routed" Overload report type
>
>      
>
>     #57: Handling of "Realm-Routed" Overload report type
>
>      
>
>      I'm assuming the name of the realm overload report in the -01 version will
>
>      be changed to realm-routed.  This issue applies independent of the actual
>
>      name of the report.
>
>      
>
>      The current behavior assumed for the realm-routed report is that the
>
>      reacting node, generally the client, will reduce the percentage of realm
>
>      routed requests sent to the reporting node.
>
>      
>
>      This is actually bad behavior and could result in the client throttling
>
>      traffic that could have been handled by the full set of servers for that
>
>      Diameter application.
>
>     [MCruz] This can only happen if the agent has miscalculated the realm overload.
>
>      
>
>      Consider the case where there are n servers for a Diameter application and
>
>      all of those server are able to handle any transaction for that
>
>      application.
>
>      
>
>      When one of those servers becomes overloaded and wishes to decrease the
>
>      number of new sessions, the primary use of realm-routed requests.  The
>
>      server will generate an OLR of type realm-routed.
>
>     [MCruz] I do not agree. Servers do not generate Realm-routed reports.
>
>      
>
>      Assume in this case that the other servers are all healthy and able to
>
>      handle new sessions.
>
>      
>
>      Clients will not have the knowledge that there are other servers in the
>
>      network able to handle the new session and will have no choice but the
>
>      throttle a percentage of the new session requests.  Even when these
>
>      throttled requests could have been handled by any of the non overloaded
>
>      servers.
>
>      
>
>      The proposal is to specify that realm-routed reports must be handled by
>
>      DOIC-supporting agents.  Agents will understand if there are other servers
>
>      able to handle the new session and, if so, can adjust the percentage of
>
>      requests routed to the overloaded server.
>
>      
>
>      Agents that handle the realm-routed OLR must remove the request from the
>
>      answer before relaying the answer to client.  This prevents the report
>
>      from being acted on by either multiple agents (if multiple are in the
>
>      path) or by an agent and a client.
>
>      
>
>      Clients that receive the realm-routed OLR must handle the OLR by
>
>      throttling the requested percentage.
>
>      
>
>  
>