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[[File:RINA-arch.png|thumb|350px|Figure 3. Example of RINA networks and IPC Process components]]
DIFs, being DAFs, can alsoin beturn the users ofuse other underlying DIFs, creatingthemselves. in thisThis wayis the recursive structurerecursion of the RINA architecture. The DAPs that are members of a DIF are called IPC Processes or IPCPs. They have the same generic DAP structure shown in Figure 2, plus some specific tasks to provide and manage IPC. These tasks, as shown in Figure 3, can be divided into three categories: data transfer, data transfer control and layer management. The categories are ordered by increasing complexity and decreasing frequency, with data transfer being the simplest and most frequent, layer management being the most complex and least frequent, and data transfer control in between. All the layers provide the same functions and have the same structure and components; all adaptation comes from configuring these components via policy <ref>I. Matta, J. Day, V. Ishakian, K. Mattar and G. Gursun. Declarative transport: No more transport protocols to design, only policies to specify. Technical Report BUCS-TR-2008-014, CS Dept, Boston. U., July 2008</ref>. This mirrors the [[separation of mechanism and policy]] common in operating systems.
As depicted in Figure 2, RINA networks are usually structured in DIFs of increasing scope,. startingThe fromhighest thelayer so-calledis lower layers and goingthe upone closerclosest to the applications., Acorresponding providerto networkemail canor beWebsites; formedthe bylowest alayers hierarchyaggregate ofand DIFsmultiplex multiplexing and aggregatingthe traffic from upper layers intoof the provider’sDAPs backbone. None ofin the provider internalhigher layers, needcorresponding to be externallyISP visiblebackbones. Multi-provider DIFs (such as the public Internet or others) float on top of the [[ISP]] layers. Only threeThree types of systems are requireddistinguished: hosts, which contain applications; interior routers, internal to a layer; and border routers, at the edges of a layer, where data goes up or down one layer.
To summarize, RINA uses the same concepts of PDU and SDU, but instead of layering by function, it layers by scope. Instead of considering that different scales have different characteristics and attributes, it considers that all communication has fundamentally the same behavior, just with different parameters. Thus, RINA is an attempt to conceptualize and parameterize all aspects of communication, thereby eliminating the need for specific protocols and concepts and reusing as much theory as possible.
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