Changes between Version 20 and Version 21 of orca-introduction

04/22/11 16:32:52 (8 years ago)
ibaldin (IP:



  • orca-introduction

    v20 v21  
    3030 * Broker. A broker mediates resource discovery and arbitration by controlling the scheduling of resources at one or more substrate providers over time. It may be viewed as a service that runswithin a GENI clearinghouse. A key principle in Orca is that the broker can have specific allocation power delegated to it by one or more substrate authorities, i.e., the substrate providers “promise” to abide by allocation decisions made by the broker with respect to their delegated substrate. This power enables the broker to arbitrate resources and coordinate allocation across multiple substrate providers, as a basis for federation and scheduling of complex slices across multiple substrate aggregates. Brokers exercise this power by issuing tickets that are redeemable for leases. 
     32Actors in ORCA are referred to by names and GUIDs. Each actor must be identifier by a unique name and GUID.  
    3234[[Image(orca-arch.png, 600px)]] 
    3638Slices are used to group resources together. A slice in a Service Manager represents resources owned by a particular user (e.g. for the purpose of an experiment). A slice in a Broker represents a portion of slivers given to a particular service manager slice from this Broker. If a Service Manager acquires resources from multiple brokers, they are not aware of each other. A slice in an authority represents the resources given by this authority to a particular service manager slice. Notice that architecturally in ORCA ''only the Service Manager knows the exact composition of the slice''. All other actors may have only a partial view of the slice.  
     40Slices are referred to by names and GUIDs. Those are normally automatically generated by various actors: 
     41 * The GUID for a lease is selected by the SM that requested it. The lease properties are a union of the resource type properties, derived by the broker from the containing resource pool, and con?guration properties speci?ed by the requesting SM. 
     42 * The GUID for a sliver is assigned by the granting AM and is returned in any lease covering the sliver. 
     43 * The GUID for a slice is assigned by the SM that wishes to create a slice for the purpose of grouping its leases. Creating a slice is not a privileged operation. The creating SM may also attach properties to the slice. 
    3846== Further reading ==