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* The discovery of [[bufferbloat]] due to the use of large buffers in the network. Since the beginning of the 1980s it was already known that the buffer size should be the minimal to damp out transient traffic bursts,<ref>L. Pouzin. Methods, tools and observations on flow control in packet-switched data networks. IEEE Transactions on Communications, 29(4): 413–426, 1981</ref> but no more since buffers increase the transit delay of packets within the network.
* The inability to provide efficient solutions to security problems such as authentication, access control, integrity and confidentiality, since they were not part of the initial design. As stated in <ref>D. Clark, L. Chapin, V. Cerf, R. Braden and R. Hobby. Towards the Future Internet Architecture. {{IETF RFC|1287}} (Informational), December 1991</ref> “experience has shown that it is difficult to add security to a protocol suite unless it is built into the architecture from the beginning”.
==Terminology==
* '''Application Entity'''. A task within a DAP directly involved with exchanging application information with other DAPs.
* '''Common Distributed Application Process (CDAP)'''. CDAP enables distributed applications to deal with communications at an object level, rather than forcing applications to explicitly deal with serialization and input/output operations. CDAP provides the application protocol component of a Distributed Application Facility (DAF) that can be used to construct arbitrary distributed applications, of which the DIF is an example. CDAP provides a straightforward and unifying approach to sharing data over a network without having to create specialized protocols.
* '''Distributed Application Facility (DAF)'''. A collection of two or more cooperating DAPs in one or more processing systems, which exchange information using IPC and maintain shared state. In some Distributed Applications, all members will be the same, i.e. a homogeneous DAF, or may be different, a heterogeneous DAF.
* '''Distributed Application Process (DAP)'''. The instantiation of a [[computer program]] executing in a processing system intended to accomplish some purpose. A Distributed Application Process contains one or more tasks or Application-Entities, as well as functions for managing the resources (processor, storage, and IPC) allocated to this DAP.
* '''Distributed IPC Facility (DIF), Layer'''. A collection of two or more DAPs cooperating to provide Interprocess Communication (IPC). A DIF is a DAF that does IPC. The DIF provides IPC services to Applications via a set of API primitives that are used to exchange information with the Application’s peer.
* '''IPC Process (IPCP)'''. An Application-Process, which is a member of a DIF and implements locally the functionality to support and manage IPC using multiple sub-tasks.
* '''Processing System'''. The hardware and software capable of executing programs instantiated as DAPs that can coordinate with the equivalent of a “test and set” instruction, i.e. the tasks can all atomically reference the same memory.
* '''Protocol Data Unit (PDU)'''. The string of octets exchanged among the Protocol Machines (PM). PDUs contain two parts: the PCI, which is understood and interpreted by the DIF, and User-Data, that is incomprehensible to this PM and is passed to its user.
* '''Resource Information Base (RIB)'''. For the DAF, the RIB is the logical representation of the local repository of the objects. Each member of the DAF maintains a RIB. A Distributed Application may define a RIB to be its local representation of its view of the distributed application. From the point of view of the OS model, this is storage.
* '''Service Data Unit (SDU)'''. The amount of data passed across the (N)-DIF interface to be transferred to the destination application process. The integrity of an SDU is maintained by the (N)-DIF. An SDU may be fragmented or combined with other SDUs for sending as one or more PDUs.
==Introduction to RINA==
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