ITU Telecommunication Standardization Sector - Study group 13, ITU-T Recommendation Q. 2963.1: Peak cell rate modification by the connection owner, 1996.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....are expected to occur and where iterative and incremental requirements elicitation techniques are needed. Andersson and Bergstand [1] used Message Sequence Charts (MSCs) MSCs are frequently used to state the requirements for telecommunications software. The current MSC standard, MSC 96 [15], provides several features aimed at enhancing the expressiveness of individual MSCs. Examples include constructs to specify the conditional, iterative, or concurrent execution of MSC sections. Anticipated exceptions and required system responses can be Fig. 1. Overview of our approach. ....

 ITU-T, Recommendation Z.120, ITU-Telecommunication Standardization Sector, Geneva, Switzerland, May 1996 (review draft version).

.... or result [14] A sequence diagram models temporal and object relationships using two dimensions, vertical for time and horizontal for objects [14] The notation of sequence diagrams is based on, and highly similar to, the Message Sequence Chart standard for the telecommunications industry [6]. 2.1.2 Composition of Scenarios A crucial challenge in describing distributed embedded systems is the composition of scenarios. In order to be adequately expressive, sequence diagrams must reflect the structures of the programs they represent. In this paper, we survey approaches to modeling ....

....a larger scenario. 8] presents a similar approach using sub scenarios. A second approach is to use a separate hierarchical diagram, instead of embedding control information in the constituent diagrams. The Message Sequence Chart (MSC) standard specifies a separate diagram to organize sub diagrams [6]. 9] explores the usage of base MSCs and high level MSCs. The high level MSC graph describes how to compose base MSC graphs to obtain sequential, conditional, iterative, and concurrent execution. 10] presents an additional example of a high level MSC graph, and applies this method to UML ....

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ITU-T. Recommendation Z.120. ITU - Telecommunication Standardization Sector, Geneva, Switzerland, May 1996.

.... of several variable bit rate (VBR) connections (called the input connections ) over one variable bit rate connection (called the VBR trunk ) This occurs for example with ATM when a number of VBR virtual channel connections (VCCs) are multiplexed over one virtual path connection (VPC) [1] which is also of the VBR type. Another example is the multiplexing of several IP flows with reservations (using a protocol such as RSVP [2] or ST.II [3] over one ATM VCC. We are interested in such multiplexing scenarios since we believe that reducing the number of connections (or reserved flows ....

ITU Telecommunication Standardization Sector - Study group 13, ITU Recommandation I.371, Traffic Control and Congestion Control in BISDN, 1995.

.... of shaper systems in terms of the network calculus theory [20]and[11] This was used in several papers to characterise the VBR service [13] and [6] The optimisation problem for the VBR service was studied in [5] 6] Renegotiation was first specified in ATM networks for CBR class service [21] and only very recently to VBR class service [14] In the reservation protocol for Integrated Services Internet networks, namely RSVP, a source is requested to refresh the reservation at given times. However, this is not intended as a mechanism for modifying the reservation parameters only, but ....

ITU Telecommunication Standardization Sector - Study group 13, ITU-T Recommandation Q.2963.1. : Peak cell rate modificationbytheconnection owner, 1996.

....shapers with two renegotiable leaky buckets (J =2)#one with rate r i and depth b i and the second with rate p i and depth always equal to zero, plus a buffer of fixed size X . In real life, examples of this service are traffic shaping done at source sending over VBR connections as defined in [14] and Internet traffic that takes the form of IntServ specification with RSVP reservation [15] 16] Indeed, we show that the RVBR service can be used to renegotiate resource reservation for Internet traffic with RSVP. In RSVP the sender sends a PATH message with a Tspec object which characterises ....

.... calculus theory [20]and[11] This was used in several papers to characterise the VBR service [13] and [6] The optimisation problem for the VBR service was studied in [5] 6] Renegotiation was first specified in ATM networks for CBR class service [21] and only very recently to VBR class service [14]. In the reservation protocol for Integrated Services Internet networks, namely RSVP, a source is requested to refresh the reservation at given times. However, this is not intended as a mechanism for modifying the reservation parameters only, but rather as the general approach for managing the ....

ITU Telecommunication Standardization Sector - Study group 13, ITU-T Recommandation Q.2963.2. Broadband integrated services digital network (B-ISDN) digital subscriber signalling system No. 2 (DSS 2) connection modification - Modification procedure for sustainable cell rate parameters, 1998.

.... 1 Introduction We consider the multiplexing of several variable bit rate (VBR) over one variable bit rate connection (called the VBR trunk ) This occurs for example with ATM when a number of VBR virtual channel connections (VCCs) are multiplexed over one virtual path connection (VPC) [9] which is also of the VBR type. Another example is the multiplexing of several IP flows with reservations (using a protocol such as RSVP [10] or ST.II [8] over one ATM VCC. Discussion on the use of VBR trunks is out of the scope of the paper, for more detailed information see [5, 3] In the ....

ITU Telecommunication Standardization Sector - Study group 13, ITU Recommendation I.371, Traffic Control and Congestion Control in B-ISDN, 1995.

.... of shaper systems in terms of the network calculus theory [5] and [13] This was used in several papers to characterise the VBR service [14]and [8] The optimisation problem for the VBR service was studied in [7] 8] Renegotiation was first specified in ATM networks for CBR class service [21] and only very recently to VBR class service [15] In the reservation protocol for Integrated Services Internet networks, namely RSVP, a source is requested to refresh the reservation at given times. However, this is not intended as a mechanism for modifying the reservation parameters only, but ....

ITU Telecommunication Standardization Sector - Study group 13, ITU-T Recommandation Q.2963.1. : Peak cell rate modification by the connection owner,1996.

....shaper composed bytwo renegotiableleaky buckets (J = 2)# one with rate r i and depth b i and the second with rate p i and depth always equal to zero, plus a buffer of fixed size X . In real life, examples of this service are traffic shaping done at source sending over VBR connections as defined in [15]andInternet traffic that takes the form of IntServ specification with RSVP reservation [16] 17] Indeed, weshow that the RVBR service can be used to renegotiate resource reservation for Internet traffic with RSVP. In RSVP the sender sends a PATH message with a Tspec (Traffic SPECification [16] ....

.... calculus theory [5] and [13] This was used in several papers to characterise the VBR service [14]and [8] The optimisation problem for the VBR service was studied in [7] 8] Renegotiation was first specified in ATM networks for CBR class service [21] and only very recently to VBR class service [15]. In the reservation protocol for Integrated Services Internet networks, namely RSVP, a source is requested to refresh the reservation at given times. However, this is not intended as a mechanism for modifying the reservation parameters only, but rather as the general approach for managing the ....

ITU Telecommunication Standardization Sector - Study group 13, ITU-T Recommandation Q.2963.2. Broadband integrated services digital network (B-ISDN) digital subscriber signalling system No. 2 (DSS 2) connection modification - Modification procedure for sustainable cell rate parameters, 1998.

....systems, we need to consider the compositions of UML sequence diagrams. At the moment the UML standard does not define compositions of UML sequence diagrams. Here we suggest to introduce high level graphs, which are similar to High Level MSCs defined in the message sequence chart standard [6], to describe compositions of UML sequence diagrams, and develop an algorithm for checking them for timing consistency. 4.1 Compositions of UML Sequence Diagrams The compositions of UML sequence diagrams can be described by a hierarchical graph. For example, Figure 2 shows a composition of UML ....

ITU-T. Recommendation Z.120. ITU - Telecommunication Standardization Sector, Geneva, Switzerland, May 1996.

....systems, we need to consider the compositions of UML sequence diagrams. At the moment the UML standard does not de ne compositions of UML sequence diagrams. In [11] we have suggested to introduce high level graphs, which are similar to High Level MSCs de ned in the message sequence chart standard [3], to describe compositions of UML sequence diagrams. The compositions of UML sequence diagrams can be described by a hierarchical graph. For example, Figure 1 shows a composition of UML sequence diagrams, which describes a simple connection establishment protocol in a telecommunication system ....

....a successful connection establishment. Like any other aspect of the speci cation and design process, compositions of UML sequence diagrams are amenable to errors, and their analysis is important. Some work have been done on analysis of the similar graphical language message sequence charts [3]. A comprehensive study of model checking of message sequence charts for temporal requirements has been given in [4] For message sequence charts with timing constraints used to describe real time systems, the veri cation problems are more complicated. In [5] some algorithms for analyzing message ....

ITU-T. Recommendation Z.120. ITU - Telecommunication Standardization Sector, Geneva, Switzerland, May 1996.

.... of shaper systems in terms of the network calculus theory [19] and [10] This was used in several papers to characterise the VBR service [12] and [5] The optimisation problem for the VBR service was studied in [4] 5] Renegotiation was first specified in ATM networks for CBR class service [20] and only very recently to VBR class service [13] In the reservation protocol for Integrated Services Internet networks, namely RSVP, a source is requested to refresh the reservation at given times. However, this is not intended as a mechanism for modifying the reservation parameters only, but ....

ITU Telecommunication Standardization Sector - Study group 13, ITU-T Recommandation Q.2963.1. : Peak cell rate modification by the connection owner, 1996.

....shapers with two renegotiable leaky buckets (J = 2) one with rate r i and depth b i and the second with rate p i and depth always equal to zero, plus a buffer of fixed size X . In real life, examples of this service are traffic shaping done at source sending over VBR connections as defined in [13] and Internet traffic that takes the form of IntServ specification with RSVP reservation [14] 15] Indeed, we show that the RVBR service can be used to renegotiate resource reservation for Internet traffic with RSVP. In RSVP the sender sends a PATH message with a Tspec object which characterises ....

.... theory [19] and [10] This was used in several papers to characterise the VBR service [12] and [5] The optimisation problem for the VBR service was studied in [4] 5] Renegotiation was first specified in ATM networks for CBR class service [20] and only very recently to VBR class service [13]. In the reservation protocol for Integrated Services Internet networks, namely RSVP, a source is requested to refresh the reservation at given times. However, this is not intended as a mechanism for modifying the reservation parameters only, but rather as the general approach for managing the ....

ITU Telecommunication Standardization Sector - Study group 13, ITU-T Recommandation Q.2963.2. Broadband integrated services digital network (B-ISDN) digital subscriber signalling system No. 2 (DSS 2) connection modification - Modification procedure for sustainable cell rate parameters, 1998.

....and the Internet Engineering Task Force (IETF) Where appropriate it will be indicated why the requirements for Customer Service Management as outlined in section 2.3 are not fully met. 3. 1 ITU T The Telecommunication Standardization Sector of the International Telecommunication Union (ITU T) [8] in recommendation M.3010 [9,11] outlined the principles for a Telecommunications Management Network (TMN) Although the TMN set of recommendations are mainly targeted at telephone type networks, the underlying principles of customer service management can be applied to Internet management as ....

ITU Telecommunication Standardization Sector (ITU-T), http://www.itu.int/ ITU-T/.

....scheme for RSVP with CL service reservation: each 30 seconds R(t) is predicted and used to compute the optimal p, r and b to generate the new Tspec. 8] The optimisation problem for the VBR service was studied in [7] 8] Renegotiation was first specified in ATM networks for CBR class service [21] and only very recently to VBR class service [15] In the reservation protocol for Integrated Services Internet networks, namely RSVP, a source is requested to refresh the reservation at given times. However, this is not intended as a mechanism for modifying the reservation parameters only, but ....

ITU Telecommunication Standardization Sector - Study group 13, ITU-T Recommandation Q.2963.1. : Peak cell rate modification by the connection owner, 1996.

....composed by two renegotiableleaky buckets (J = 2) one with rate r i and depth b i and the second with rate p i and depth always equal to zero, plus a buffer of fixed size X . In real life, examples of this service are traffic shaping done at source sending over VBR connections as defined in [15] and Internet traffic that takes the form of IntServ specification with RSVP reservation [16] 17] Indeed, we show that the RVBR service can be used to renegotiate resource reservation for Internet traffic with RSVP. In RSVP the sender sends a PATH message with a Tspec (Traffic SPECification ....

....30 seconds R(t) is predicted and used to compute the optimal p, r and b to generate the new Tspec. 8] The optimisation problem for the VBR service was studied in [7] 8] Renegotiation was first specified in ATM networks for CBR class service [21] and only very recently to VBR class service [15]. In the reservation protocol for Integrated Services Internet networks, namely RSVP, a source is requested to refresh the reservation at given times. However, this is not intended as a mechanism for modifying the reservation parameters only, but rather as the general approach for managing the ....

ITU Telecommunication Standardization Sector - Study group 13, ITU-T Recommandation Q.2963.2. Broadband integrated services digital network (B-ISDN) digital subscriber signalling system No. 2 (DSS 2) connection modification - Modification procedure for sustainable cell rate parameters, 1998.

....that helps in software maintenance and reengineering [10] Recently, the intuitive, graphical notation of MSCs increased their popularity within the software engineering community and motivated a standardization effort. The MSC standard as defined by the ITU T in Recommendation Z. 120 [12] introduces two basic concepts: basic MSCs (bMSCs) and High Level MSCs (hMSCs) A bMSC consists of a set of processes that run in parallel and exchange messages in a one to one, asynchronous fashion. An hMSC graphically combines references to basic MSCs to describe parallel, sequential, iterating, ....

....order determined by the flow of control within each process in the MSC along with a causal dependency between the events of sending and receiving a message. To facilitate the specification of real time systems, a few extensions to MSCs have been proposed 1 to express timing constraints: timers [12], interval delays [2, 15] and timing markers [7, 6] The proposed extensions evolved independently and differ in terms of their expressiveness and support for analysis. Further, all proposed analysis of MSCs with timing constraints have been so far limited to basic MSCs. In an effort to help ....

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ITU-T. Recommendation Z.120. ITU - Telecommunication Standardization Sector, Geneva, Switzerland, May 1996. Review Draft Version.

....Economiques et de Gestion, Universit e de Sfax Sfax, Tunisia, hanene swen.uwaterloo.ca 2 Electrical and Computer Engineering, University of Waterloo Waterloo, Ontario N2L 3G1, Canada, sleue swen.uwaterloo.ca Abstract. The latest ITU T standard syntax of Message Sequence Charts (MSCs) [16] offers several operators to compose MSCs in a hierarchical, iterating, and nondeterministic way. However, current tools operate on MSCs that describe finite, deterministic behavior. In this paper, we describe the architecture and the partial implementation of Mesa, an MSC based tool that ....

....the standardized syntax of This work was partly supported by the Information Technology Research Centre of the Province of Ontario and by the National Science and Engineering Research Council of Canada. ObjecTime Limited provided further support. MSCs by the ITU T in Recommendation Z. 120 [16]. In other words, we view Mesa as a front end to various methods and tools, and hence code synthesis from MSC specifications is an essential objective. We currently envisage synthesis of SDL [14] ROOM [22] and Promela [11] all of which enjoy support by mature, industrial strength CASE tools. A ....

[Article contains additional citation context not shown here]

ITU-T. Recommendation Z.120. ITU - Telecommunication Standardization Sector, Geneva, Switzerland, May 1996. Review Draft Version.

....languages like SDL or PROMELA describe the process behaviour explicitly, leaving message flows to be inferred, MSCs specify explicit message flows while other details of process behaviour must be inferred from the specification. The syntax of MSCs is described in the ITU T Recommendation Z. 120 [IT96] MSCs are frequently used both formally and informally for the description of message flow amongst communicating, concurrent processes. They have found their way into many software engineering methodologies and toolsets, such as SDL tools and environments [OFMP 94, Lab95] Object oriented ....

....with names a and b and increasing values a=1 and b=2. To model the message behaviour of MSCs in PROMELA we choose channels with capacity 1, one for each message arrow in the chart. This represents the invariant that any given message is either on the way (in which case there is a 3 C.f. IT96] A sequential execution of two nodes that are related by an edge is described byt the seq operator. and The seq operator denotes the weak sequencing operation where only events on the same instance are ordered . Concerning the semanitcs of conditions, c.f. IT95] Note that the semantics of ....

ITU-T, Recommendation Z.120, ITU - Telecommunication Standardization Sector, Geneva, Switzerland, May 1996, Review Draft Version.

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"ITU-T recommendation Z.120. Message Sequence Charts (MSC'96)," May 1996, ITU Telecommunication Standardization Sector. 150

....requirements analysis, formal verification, scenarios, concurrent state machines, deadlock freedom, realizability, synthesis. 1 Introduction Message Sequence Charts (MSCs) are a commonly used visual description of design requirements for concurrent systems such as telecommunications software [20, 24], and have been incorporated into software design notations such as UML [25] Requirements expressed using MSCs have been given formal semantics, and hence, can be subjected to analysis. Since MSCs are used at a very early stage of design, any errors revealed during their analysis yield a high ....

....executions definable using them. Our definition captures the essence of the basic MSCs of the ITU standard This interpretation is consistent with our concurrent state machine interpretation of MSCs in the rest of this paper. NA UR double Figure 2: Implied MSC bad : Incorrect fuel mix MSC 96 [20], and is analogous to the definitions of labeled MSCs given in [3, 4] Let P = fP 1 ; P n g be a set of processes, and Sigma be a message alphabet. We write [n] for f1; ng. We use the label send(i,j,a) to denote the event process P i sends the message a to process P j . ....

ITU-T recommendation Z.120. Message Sequence Charts (MSC'96), May 1996. ITU Telecommunication Standardization Sector.

....portion of the image is divided into 16 Theta 16 blocks, and to each block is assigned either a single motion vector, a set of four motion vectors, or a set of intra block parameters. The motion model used by our matching pursuit system is identical to the advanced prediction model used in TMN[12], which is a specific implementation of H.263. For more details on these methods, one can consult the H.263[13] and TMN[12] documents. 2.2.3 Matching Pursuit Residual Coding After the motion prediction image is formed, it is subtracted from the original image to produce the motion residual. This ....

....a set of four motion vectors, or a set of intra block parameters. The motion model used by our matching pursuit system is identical to the advanced prediction model used in TMN[12] which is a specific implementation of H.263. For more details on these methods, one can consult the H. 263[13] and TMN[12] documents. 2.2.3 Matching Pursuit Residual Coding After the motion prediction image is formed, it is subtracted from the original image to produce the motion residual. This residual image is coded using a discrete twodimensional matching pursuit algorithm with a properly chosen dictionary. Neff ....

ITU Telecommunication Standardization Sector LBC-95, Video Codec Test Model TMN5.

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ITU Telecommunication Standardization Sector - Study group 13, ITU-T Recommendation Q. 2963.1: Peak cell rate modification by the connection owner, 1996.

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ITU Telecommunication Standardization Sector (ITU-T). The Directory: Authentication Framework. In Recommendation X.509, 1997.

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ITU Telecommunication Standardization Sector - Study group 13, ITU-T Recommendation Q. 2963.1: Peak cell rate modification by the connection owner, 1996.

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ITU Telecommunication Standardization Sector LBC-95, Study Group 15, Working Party 15/1, Expert's Group on Very Low Bitrate Visual Telephony, from Digital Video Coding Group, Telenor Research and Development.

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