Changes between Version 6 and Version 7 of orca-introduction

04/22/11 13:47:23 (8 years ago)
ibaldin (IP:



  • orca-introduction

    v6 v7  
    1616 * Guest - a distributed software environment running within collection of slivers configured to order, possibly from different substrate providers. Some guests will be long-running services that require different amounts of resources at different stages of execution. The guests may range from virtual desktops to complex experiments to dynamic instantiations of distributed applications and network services. 
     18== Principles of operation == 
     20There are three basic actor roles in the architecture, representing the providers, consumers, and 
     21intermediaries respectively. There can be many instances of each actor type, e.g., representing di?erent substrate providers or resource consumers. 
     23 * Authority or Aggregate Manager (AM). An authority actor controls access to some subset 
     24of the substrate components. It corresponds directly to the aggregate manager (AM) in GENI. 
     25Typically, an authority controls some set of infrastructure resources in a particular site, autonomous 
     26system, transit domain, administrative domain, or component aggregate comprising a set of servers, 
     27storage units, network elements, or other components under common ownership and control. 
     28Terminology note. The term site or site authority (e.g., a cluster site or hosting center) is often 
     29used to refer to a substrate authority/AM, as a result of our roots in virtual cloud computing. For 
     30network substrates we are using the term domain authority more often when it is appropriate. 
     32 * Slice/Service Manager (SM) or Slice Controller. This actor is responsible for creating, 
     33con?guring, and adapting one or more slices. It runs on behalf of the slice owners to build each 
     34slice to meet the needs of a guest that inhabits the slice. 
     35Terminology note. This actor was originally called a service manager in SHARP (and in the Shirako 
     36code) because the guest was presumed to be a service. As GENI has developed, we have adopted 
     37the term slice controller because the actor’s role is to control the slice, rather than the guest itself, 
     38and because in GENI the guest is an experiment rather than a service. Slice Manager (also SM) 
     39is also OK since the “controller” is properly speaking a plugin module to the actor itself.  
     41 * Broker. A broker mediates resource discovery and arbitration by controlling the scheduling of 
     42resources at one or more substrate providers over time. It may be viewed as a service that runs 
     43within a GENI clearinghouse. A key principle in Orca is that the broker can have speci?c allocation 
     44power delegated to it by one or more substrate authorities, i.e., the substrate providers “promise” 
     45to abide by allocation decisions made by the broker with respect to their delegated substrate. 
     46This power enables the broker to arbitrate resources and coordinate allocation across multiple 
     47substrate providers, as a basis for federation and scheduling of complex slices across multiple 
     48substrate aggregates. Brokers exercise this power by issuing tickets that are redeemable for leases. 
    1851== Further reading ==