| RE: [cosmos-dev] question on management domain and brokers |
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Hi Hubert, OK, here goes… >> I
remember Martin said in the meeting that data managers contact the management
domain, not a broker. The management domain has a UDDI registry, which is
a logical place to start to discover location of brokers. My recollection is that we decided NOT to
make UDDI a requirement for a DomainManager
implementation. Regardless, the idea was that an external client would go to
the DomainManager to find out about all available DataBrokers. If data managers know how to contact brokers directly,
the clients can do that as well. Then what's the use of the management
domain? From the point of view of a DataManager, I’m not sure there is any need for a DomainManager. To me, it makes more sense to deploy DataManagers with an affinity to one or more well-know
brokers (well known from the DataManager’s
point of view) so that the DataManager can use WSDM
Advertisement to notify the DataManager of it’s
availability, and let the DataBroker roll up its
knowledge of available DataManagers to the DomainManager if one exists. From the client point of view,
it seems easier to be able to bootstrap use cases from a single point (the DomainManager), and possibly delegate some of the client
use case logic (for example, find me the DataManager
for X) to the DomainManager. What I'm trying to clarify is not the "merged
domain manager / broker" simplified scenario, but the real multi-broker
scenario. "Visit all brokers until you find one that works" is not an
elegant solution. Was that intended to be a smarmy comment? ;-)
In any case, a client will be “visiting brokers” one way or
another. Taking your UDDI case, each client would be forced to visit the known
brokers in order to find an appropriate match for a given request. If you
interpose the DomainManager, then it’s possible
to offload some of that client implementation into the DomainManager
to simplify the marriage-making and allow for incremental optimization without
the need to update clients. Martin, Jimmy, Chris, please wade in! Cheers, Joel The contents of this e-mail are intended for the named addressee only. It contains information that may be confidential. Unless you are the named addressee or an authorized designee, you may not copy or use it, or disclose it to anyone else. If you received it in error please notify us immediately and then destroy it.
Hi all, My understanding is that
the DataManager contacts its DataBroker, and the DomainManager only knows about
DataBrokers . The nice thing about this is we can easily support the ‘No
DomainManager’ simplified scenario. We can support routing either
naively (basically visiting each know DataBroker until we get one that works
for a particular request), or we can route based on prior knowledge (sticky
sessions and/or routing based on cached information about similar request).
This could be a place for ‘value-add’.
Good idea.
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