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PNUT: Protocols configured for Network and User Transmissions
... Details about the QoS manager and the determination of user preferences are described in [12, 9]. The function selection process and triggering of the reconfiguration can be found in [8]. ...
... In this section, we will briefly discuss both of these processes. A detailed description is provided in [8]. Since the control channel is required for the management of the data channels, it needs to be set up before any requests regarding data channels are handled. ...
... Thirdly, by developing PNUT as an user-level protocol, we believe it will be easily distributed as part of applications rather than as part of the kernel. Finally, it has been shown that PNUT is able to provide high performance implementations even as an user-level implementation [8]. ...
This paper shows the use of protocols dynamically generated for a particular network environment and an application’s requirements.
We have developed a novel system called PNUT (Protocols configured for Network and User Transmissions), which can be used
to dynamically generate protocols. A distributed MPEG player has also been developed using PNUT to demonstrate the need for
adaptive protocols that can reconfigure their functionality as the operating environment changes. One of the key features
of PNUT is that it allows for the dynamic reconfiguration of the protocol stack, which we believe is necessary when developing
protocols for mobile computing environments. The paper also shows how intermediate servers can be used to provide better services
to the mobile application. Furthermore, we show how intermediate servers can be used to allow mobile applications using PNUT
to interact with servers based around traditional applications
... Details about the QoS manager and the determination of user preferences are described in [12,9]. The function selection process and triggering of the reconfiguration can be found in [8]. ...
... In this section, we will briefly discuss both of these processes. A detailed description is provided in [8]. ...
... Thirdly, by developing PNUT as an user-level protocol, we believe it will be easily distributed as part of applications rather than as part of the kernel. Finally, it has been shown that PNUT is able to provide high performance implementations even as an user-level implementation [8]. ...
This paper shows the use of protocols dynamically generated for a particular network environment and an application's requirements. We have developed a novel system called PNUT (Protocols configured for Network and User Transmissions), which can be used to dynamically generate protocols. A distributed MPEG player has also been developed using PNUT to demonstrate the need for adaptive protocols that can reconfigure their functionality as the operating environment changes. One of the key features of PNUT is that it allows for the dynamic reconfiguration of the protocol stack, which we believe is necessary when developing protocols for mobile computing environments. The paper also shows how intermediate servers can be used to provide better services to the mobile application. Furthermore, we show how intermediate servers can be used to allow mobile applications using PNUT to interact with servers based around traditional applications.
... These transparently modify the applications' behaviour similar to the work done by [Fox96]. Finally, we use tailored communication protocols that can be configured to suit the particular network environment and the application's requirements [Des98]. By working in these three dimensions, we are able to best support the requirements of the user, given the currently available resources. ...
... A tailored communication protocol is a communication subsystem specifically developed to support the application's requirements and the network environment. It has been shown in [Des98] that these protocols can be dynamically generated, using automated techniques, to improve application performance. ...
... PNUT manages the data channels using out-of-band signalling on a control channel. Further details about PNUT can be found in [Des98] The MPEG player uses three data channels to transfer the different frame types as shown in Figure 8. The channel containing the I-frames is always uses a reliable protocol (i.e. ...
With the growth of mobile computing, users will have simultaneous access to multiple networks, each with different characteristics, services and costs. This paper introduces TOMTEN (TOtal Management Of Transmissions for the ENd-user), a framework for managing resources in this environment. TOMTEN is a reactive framework that is only active when either the application is started up or the user indicates dissatisfaction with a current session. The framework being reactive, positions it in contrast with all Quality of Service (QoS) frameworks proposed to date, since these are continuously trying to predict the user's perceived quality and preferences. In addition to this reactive QoS, TOMTEN also supports application adaptivity within the framework. Application adaptivity in TOMTEN does not require modifications to the application as it is done transparently using proxy modules. This paper presents the TOMTEN framework and shows how it attempts to assist the user in maximising their res...
... The user applications we used to conduct testing were TCP-based and consisted of an MPEG video player and a waveform audio player. The video player was based on the MPEG player developed in UC Berkeley but with additional modifications to make it operate in a client/server environment [DESI98]. At the beginning of the experiment, the MH requested an audio and/or a video file(s) from the CH. ...
... Proxies can also be used to implement tailored communications protocols to cater for particular link characteristics. Examples of such systems are presented in [23]. ...
A novel, server-centric architecture for adapting media content to suit the operational environment for heterogeneous devices and networks is presented. The given architecture, so called MARCH, exhibits several advantages over traditional static proxy solutions. The viability of the MARCH framework has been demonstrated through a prototype implementation.
With the growth of mobile computing, users will have simultaneous access to multiple overlaid networks, each with different characteristics, services and costs. This paper introduces TOMTEN (TOtal Management Of Transmissions for the ENd-user), a framework for managing resources in both this type of environment as well as the traditional single network environment. TOMTEN is a reactive framework that is only activated when either the application is started or the user indicates dissatisfaction with a current session. The reactive architecture of TOMTEN also supports application adaptivity. Application adaptivity in TOMTEN does not require modifications to the application and is done transparently using proxy modules.
A protocol bypass is a fast processing path which is used for some data units, for instance for large data packets. It can provide conformance with standardized layered protocol system like OSI, together with some of the performance benefits of a "lightweight" pro-tocol. The concept is discussed as it applies to the movement of user data by the OSI transport and session protocols, with some implementation experience, and an outline for an approach to formally deriving bypass specifications from protocol specifications is given. This outline uses some steps which must still be proven to be practical. Correct interleaving of data units from the two paths is a major concern, especially with mul-tiple asynchronously specified layers. It seems that the difficulty can be overcome and the concept has promise. In the (rather limited) implementation, bypassing consistently outperformed parallel processing as a means of performance enhancement.
An abstract is not available.
Current communication systems are either based on connectionless (CL) or connection-oriented (CO) protocols. Many mechanisms have been proposed in each case but present CL and CO solutions are not conceptually related and there is a design gap between their definition and use. It is shown how CL and CO approaches appear as two specific cases of a much more general concept, the partial order connection (POC), which is presented here. A POC is an end-to-end connection that provides a partial order service where the objects can be dellivered to the users in an order different from the transmitted one. Starting from this new concept, design principles of a general multimedia Transport connection are then introduced that allow the definition of a multimedia Quality of Service (QoS) consistent with general applications requirements.
The current generation of protocol architectures, such as TCP/IP or the ISO suite, seem successful at meeting the demands of todays networks. However, a number of new requirements have been proposed for the networks of tomorrow, and some innovation in protocol structuring may be necessary. In this paper, we review some key requirements for tomorrow's networks, and propose some architectural principles to structure a new generation of protocols. In particular, this paper identifies two new design principles, Application Level Framing and Integrated Layer Processing. Additionally, it identifies the presentation layer as a key aspect of overall protocol performance.