When allocating capacity to a slice creation service

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calls, respectively. When allocating capacity to a slice creation service like plc.scs , the RSpec includes three pieces of information: (1) specifications for the resources in the pool; (2) the name of the slice authority that is allowed to create slices using the pool (e.g., plc or plc.japan ); and (3) the SSL certificate for the corresponding slice authority. 22
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4.10 Resource Specification A resource specification ( RSpec ) is an abstract object used throughout Planet- Lab. It is the main object maintained by a node manager and slice creation service (representing both virtual machines and resource pools), and it is the primary com- ponent of the record maintained for each slice by a slice authority (representing the attributes of a PlanetLab-wide slice). As such, many of the methods supported by these components operate on RSpec s. Similarly, a ticket is an RSpec signed by a slice authority. An RSpec can be viewed as a set of attributes, or name/value pairs. For ex- ample, the following set of attributes correspond to the default resources allocated to a VM in the current system (the parenthetic comment gives the corresponding unit): cpu share = 1 disk quota = 5 (GB) mem limit = 256 (MB) base rate = 1 (Kbps) burst rate = 100 (Mbps) sustained rate = 1.5 (Mbps) Despite this example, an RSpec is actually not a flat list of attributes; it has some structure. More accurately, an RSpec can be viewed as the base class of an object hierarchy, as shown in Figure 3. Class PoolRSpec represents a resource pool, class SliceRSpec represents a PlanetLab-wide slice, and class VServer- Slice represents a vserver-based VM. SliceRSpec AuxiliaryRSpec LinkRSpec OperationRSpec PoolRSpec RSpec VServerRSpec Figure 3: RSpec object hierarchy. LinkRSpec and OperationRSpec are future additions to the object hierarchy and thus not yet defined. A LinkRSpec represents a reference to another RSpec , possibly with reduced capabilities, that can be created by any client as a means of passing a reference to an RSpec that does not convey the full capabilities of the 23
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RSpec itself. An OperationRSpec is a functional object that permits a client to execute a privileged operation, such as one supported by Proper [7]. Note that an implementation may define other classes within this hierarchy as long as those classes do not affect the behavior of the named classes. For example, the current implementation defines classes ParentRSpec and PrimaryRSpec as base classes for PoolRSpec and SliceRSpec respectively, and a class VmmBase as an intermediate class between SliceRSpec and VServerSlice . Because RSpec s are commonly passed over the network, for example between a slice authority and a slice creation service, it is necessary to define an external representation. RSpec s are currently represented in XML. 5 Security Architecture This section summarizes the security architecture supported by the various com- ponents just described. It describes how nodes security boot, how users create and access slices, and how services authenticate themselves to each other and to PLC.
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