ITU. Recommendation X.509, The Directory: Authentication Framework (also ISO/IEC 9594-8, 1995). International Telecommunications Union, Telecommunication Standardization Sector(ITU-T), June 1997.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....databases. The performance, reliability, and availability requirements of data access operations are demanding. Thousands of retrievals must be executed in a second and the allowed down time is only a few seconds per year. A telecommunication database system must offer realtime access to data [12, 13]. This is due to the fact that most read requests are for logic programs that have exact time limits. If the database cannot give a response within a specific time limit, it is better not to waste resources and hence abort the request. As a result of this, the request management policy should ....

ITU. Draft Q.1224 Recommendation IN CS-2 DFP Architecture. ITU, International Telecommunications Union, Geneva, Switzerland, 1996.

....an approximate, but faster, solution [9, 163, 176] The output of this centralized optimization problem is then distributed to the circuit switches. In other cases, researchers have treated the problem as an incremental problem in which each circuit request is routed individually as it arrives [169, 8, 13]. The circuit routing can be done at the source or hopby hop. Chapter 6 describes some of these signaling and routing protocols that have been proposed. This chapter focuses on the first question, how to estimate the traffic matrix between boundary routers and then use the estimate to provision ....

ITU Telecommunication Standardization Sector. Link capacity adjustment scheme (LCAS) for virtual concatenated signals. International Telecommunication Union, Recommendation G.7042/Y.1305 edition, February 2003.

....or features often interfere with each other in unexpected and undesirable ways the so called feature interaction problem [3] IP Telephony or VoIP (Voice over IP) is a hot topic that has attracted significant commercial and research interest. The main standards deployed in this area are H. 323 [6] and SIP (Session Initiation Protocol [9] Although H.323 is more widely deployed and more mature, SIP is more flexible and better oriented towards providing new services. For example it is being used for presence and instant messaging services, and has been adopted for use in 3G mobile ....

ITU. Packet-Based Multimedia Communication Systems. ITU-T H.323. International Telecommunications Union, Geneva, Switzerland, 2000.

....features. However the CRESS tools also support more direct implementation through SIP CPL, SIP CGI and VoiceXML. Industry seems to prefer graphical notations. Several graphical representations have been used to describe communications services. SDL (Specification and Description Language [9]) is the main formal language used in communications. Although it has a graphical form, SDL is a general purpose language that was not designed particularly to represent services. As a result, SDL service descriptions are not especially convenient or accessible to nonspecialists. MSCs (Message ....

ITU. Specification and Description Language. ITU-T Z.100. International Telecommunications Union, Geneva, Switzerland, 2000.

....language used in communications. Although it has a graphical form, SDL is a general purpose language that was not designed particularly to represent services. As a result, SDL service descriptions are not especially convenient or accessible to nonspecialists. MSCs (Message Sequence Charts [8]) are higher level and more straightforward in their representation of services. However neither SDL nor MSCs can readily describe the notion of features and feature composition. Several notations have been specially devised for communications services. Among these, UCMs (Use Case Maps [2, 3] ....

ITU. Message Sequence Chart (MSC). ITU-T Z.120. International Telecommunications Union, Geneva, Switzerland, 2000.

....window for flow control. One might ask, why just LAPB An early descendant of the ISO HDLC protocol, it could be considered obsolete today. However, it is simple enough and implements all classic functions of OSI data link layer. It is also succeeded by several important protocols. e.g. LAPD [6] is very similar to LAPB, with more complex addressing scheme and slightly different, but less efficient timeout recovery mechanism [7] LAPDm [8] is specialised for use over the radio channel of GSM networks. From the didactic point of view, it is therefore reasonable to explain LAPB first and ....

ITU, ITU-T Recommendation Q.921, International Telecommunication Union, 1993

....view in an appropriate sequence. As it is difficult to understand the station procedures while ignoring the process as a whole, the communication process must be explained first and only then the station procedures in somewhat more detail. THE LAPB PROTOCOL LAPB (Link Access Procedure Balanced) [5] is a classic ITU T standardised data link layer protocol. It is connection oriented and based on Go Back N ARQ method for error correction and sliding window for flow control. One might ask, why just LAPB An early descendant of the ISO HDLC protocol, it could be considered obsolete today. ....

....P (poll) F (final) or space (none of the above) The N(S) parameter is given only for information frames. No details of actual frame construction in terms of fields and bits are given. Program Limitations The information transfer phase of LAPB is implemented following the ITU T recommendation [5], except for the following simplifications. The explicit data flow control by means of RNR frames is not considered. Frames are numbered modulo 8 only, although the recommendation also allows for modulo 128 sequencing. Where the recommendation admits several alternative actions to be taken by a ....

ITU, ITU-T Recommendation X.25, International Telecommunication Union, 1993

....the idea of expressing component (and system) variability in terms of groups of interchangeable modules. Numerous techniques have been proposed for architectural descriptions. Examples include specification languages which support a box and line type block diagram notation, such as ROOM [52] SDL [51,35], and ModeChart [36] architectural description languages such as Aesop [26] Wright [6] UniCon [53] Rapide [43] and ACME [27] and other formal notations such as those used in [49] 31] and [18] All of these techniques refer to the notions of component, connector, and configuration to ....

ITU. CCITT Specification and Description Language, Recommendation Z.100. International Telecommunications Union, 1993.

....we mean one in which one party submits a request, possibly supported by one or more credentials, that must comply with another party s policy if it is to be granted. Scenarios that require authorization decisions include content advising [25] mobile code execution [11] public key infrastructure [6, 29, 18, 9, 26], and privacy protection [22, 20] Electronic commerce is one class of services in which authorization decisions play a prominent role. Merchants 1 and customers both have valuable resources at risk and must have appropriate policies in place before authorizing access to these resources. An ....

....Alice says partly trusted(Joe) Alice says partly trusted(Peg) Alice delegates is key( Key, User)1 to threshold(1,fully trusted 1) Alice delegates is key( Key, User)1 to threshold(2,partly trusted 1) Of course, one can also use weighted dynamic threshold structures. In X. 509 [6], certification authorities (CAs) certificates are chained together to establish a key binding. For such delegation chains to be really meaningful, the certificates on such chains must also imply delegations. Since there is no limit on the length of delegation chains, all such delegations have ....

ITU-T Rec. X.509 (revised), The Directory - Authentication Framework, International Telecommunication Union, 1993.

....Q. wrp##Uv#yr)#Fitness for purpose of Videotelephony in Face to Face Situations 9ryvo oor. hiyr#U fr)#Q###Qiyvp 8 8#9ryvo oor. hiyr#Iir. #A314 Tel MuM DS P 004 b1 8 #. hp#hy#9h#r# s#9ryvo oor. ## ##ur#8 8)#30#April 1999 6p#hy#9h#r# s#9ryvo oor. ## ##ur#8 8)#30 June 1999 Uv#yr# s#9ryvo oor. hiyr)#Specifications of Fitness for Purpose ....

....of the results, the project aims to express the experimental results as guidelines to be used by a target audience of codec manufacturers, system integrators, service providers and standardisation bodies. The guidelines may also to a lesser extent be used by end users in actual usage situations. The process by which the experimental results (reported in Deliverable 3) were transformed into guidelines is illustrated in Figure 1. Review of guideline application problems Review of target audiences Review of candidate guideline formats Specification of Vis vis guideline format ....

[Article contains additional citation context not shown here]

ITU (1999). International Telecommunication Union (ITU) Home Page.

....possibly supported by one or more credentials, that must comply with another party s policies if it is to be granted. Scenarios that require authorization decisions include electronic commerce, health care [2, 7] content advising [28] mobile code execution [12] public key infrastructure [9, 30, 19, 11, 27], and privacy protection [24, 23] Authorization in Internet services is significantly different from authorization in centralized systems or even in distributed systems that are closed or relatively small. In these older settings, authorization of a request is divided into authentication ( who ....

ITU-T Rec. X.509 (revised), The Directory - Authentication Framework, International Telecommunication Union, 1993.

....is what information is bound to public keys Earlier PKI proposals are designed for authentication and bind a globally unique identity to each public key. In this section, we give an overview of several existing identity based PKI s. X.509 The Directory Authentication Framework, known as X. 509 [39], defines a format for digital certificates. In a certificate, a public key is bound to the distinguished name (DN) of the key holder. For a large community of users, multiple CA s are needed. These 9 CA s sign certificates for each other. When two users certified by different CA s want to ....

....expressions is specified in [12] 2.5.3 SPKI SDSI SPKI (Simple Public Key Infrastructure) and SDSI (Simple Distributed Security Infrastructure) were started independently. Both of them were motivated by the inadequacy of public key infrastructures based on global name hierarchies, such as X. 509 [39] and Privacy Enhanced Mail (PEM) 43] Later, SPKI and SDSI merged into a collaborative effort, SPKI SDSI 2.0, about which the most up to date documents are [23, 25, 26] The SPKI SDSI approach shares many views with the trust management approach. For example, it aims at developing a standard ....

ITU-T Rec. X.509 (revised), The Directory - Authentication Framework, International Telecommunication Union, 1993.

....object oriented, fault tolerant, and distributed database management system. The RODAIN architecture is designed to fulfill the requirements derived from the most important telecommunications standards including Intelligent Network (IN) GRKK93] Telecommunications Management Network (TMN) ITU92c] and Telecommunication Information Networking Architecture (TINA) AKS93] The most challenging issue in designing a real time transaction processing system for telecommunications is the handling of transactions having very different characteristics. A telecommunication database system should ....

ITU. Principles for a Telecommunications Management Network. Recommendation M.3010. ITU, International Telecommunications Union, Geneva, Switzerland, 1992.

....necessity in telecommunications. A telecommunications database has different types of users all of which have a different view to the data. In telecommunications, the data views differ not only in data but also in metadata. Thus some users might want to see data in database as an X. 500 Directory [ITU92a] while others want to see it as as X.700 Management Information Tree [ITU92b] It is possible that not all metadata transformations are possible in the object data model. Finally, a telecommunications database should be compatible with other object standards, especially with standards that deal ....

ITU. Information Technology -- Open Systems Interconnection -- The Directory: Abstract Service Definition. Recommendation X.511. ITU, International Telecommunications Union, Geneva, Switzerland, 1992. 54

....names can be interpreted as distributed roles. 1 Introduction Rivest and Lampson introduced linked local names in the Simple Distributed Security Infrastructure (SDSI) 17] They were motivated by the inadequacy of public key infrastructures based on global name hierarchies, such as X. 509 [11] and Privacy Enhanced Mail (PEM) 12] After version 1.1, the SDSI effort merged with the Simple Public Key Infrastructure (SPKI) effort. The result is SPKI SDSI 2.0, about which the most up to date documents are [7, 9, 10] # This paper appears in Proceedings of the 13th IEEE Computer Security ....

ITU-T Rec. X.509 (revised), The Directory - Authentication Framework, International Telecommunication Union, 1993.

....may be done through several VP links, which is called VC switching. Aku Pysti Blocking in Third Generation Radio Access Networks 5 Transmission path VP link VP connection VC link VC connection Physical link VP VC VP VC Physical link Figure 2. 2: Relationship between VCs, VPs and transmission [ITU I.311] Figure 2.3 illustrates the difference between VC and VP switching. In VP switching cell forwarding and VC connection set up are fast, because only first two octets of the cell have to be checked and changed. In VC switching both the VPI and VCI are checked and changed according to where the ....

....In VP switching cell forwarding and VC connection set up are fast, because only first two octets of the cell have to be checked and changed. In VC switching both the VPI and VCI are checked and changed according to where the cells are flowing to. Figure 2. 3: Representation of VC and VP switching [ITU I.311] 2.3 Description of the connection characteristics Every connection may have its own characteristics. But the switch has to be told about them. When opening a new connection, the user tells the switch what are the characteristics of the data flow it wants to create. If the network accepts the ....

ITU-T Recommendation I.311. B-ISDN general network aspects. International Telecommunication Union. 1993. ( www.itu.int )

....possibly supported by one or more credentials, that must comply with another party s policies if it is to be granted. Scenarios that require authorization decisions include electronic commerce, health care [2, 7] content advising [28] mobile code execution [12] public key infrastructure [9, 30, 19, 11, 27], and privacy protection [24, 23] Authorization in Internet services is significantly different from authorization in centralized systems or even in distributed systems that are closed or relatively small. In these older settings, authorization of a request is divided into authentication ( who ....

ITU-T Rec. X.509 (revised), The Directory - Authentication Framework, International Telecommunication Union, 1993.

....Node Infrastructure ICSS 2000 Paper #87 6 This two segment, encrypted network tunnel architecture permits the desired virtual localization of application services. It also provide the advantage that, since data is monitored before encryption, advanced protocols such as T.120 [7] H. 323[8], and other application specific protocols can go through the Centers firewall using the encrypted tunnel. This function is critical for ISE and other NASA programs, which will develop a number of distributed collaborative applications each of which may use several different high end protocols. ....

ITU Study Group 16, H.323 Standard Version 2, International Telecommunications Union (ITU), 1998.

....3 IsoWAN Node Infrastructure ICSS 2000 Paper #87 6 This two segment, encrypted network tunnel architecture permits the desired virtual localization of application services. It also provide the advantage that, since data is monitored before encryption, advanced protocols such as T. 120 [7], H.323[8] and other application specific protocols can go through the Centers firewall using the encrypted tunnel. This function is critical for ISE and other NASA programs, which will develop a number of distributed collaborative applications each of which may use several different high end ....

ITU-T, T-120 Standard, International Telecommunications Union (ITU), 1998

....rate goes beyond the allocated bandwidth as shown in Fig. 4. To avoid this, we do not reduce the coding rate (as in TM5) but increase the allocated bandwidth by the bandwidth renegotiation with the network in this paper. The bandwidth re negotiation can be performed through the signaling protocol [6]. Or, we can utilize a Fast Reservation Protocol [or ABT (ATM Block Transfer) 7] for fast bandwidth renegotiation. Note that in the case of FRP, the concept of burst cannot be applied to our case and we may need some modification to FRP. A further study is required about the implementation ....

....hundred times as large as that of original TM5. To avoid this queue length explosion, we do not reduce the coding rate (as in TM5) but increase the allocated bandwidth by the bandwidth re negotiation with the network. The bandwidth re negotiation can be performed through the signaling protocol [6] or Fast Reservation Protocol (FRP) or ABT (ATM Block Transfer) 7] Note that in the case of FRP, the concept of burst is not applied in our case and we need some modification to FRP. Namely, the use of RM cells should be extended to allow the rate changes. If on the fly FRP signaling is ....

ITU-T Draft Standard Q.2963, Preliminary Draft. International Telecommunication Union, 1995.

.... we have several service classes defined in the standardization bodies; CBR (Continuous Bit Rate) VBR (Variable Bit Rate) and ABR (Available Bit Rate) service classes (Newman 1994) The first two classes are now called DBR (Deterministic Bit Rate) and SBR (Statistical Bit Rate) respectively, in ITU T (ITU T 1995a) Each of the above service classes defines an associated QoS (Quality of Service) and supposes the appropriate traffic class to be applied. In the case of the video transfer, either of DBR or SBR service classes may be applied since the video requires real time transfer, but tolerates a small ....

....the connection reserves is increased and decreased according to the picture or GoP sizes. With this control method, higher bandwidth utilization can be expected while keeping the video quality high. For this purpose, we can utilize the bandwidth renegotiation process via the signaling protocol (ITU T 1995b) while it has not yet been standardized. In employing this method, we have two alternatives. One is to use the buffering method in which a picture is buffered at the source when the allocated bandwidth, PCR, is in short to transmit a picture (Grossglauser et al. 1995) Reininger et al. 1995) ....

ITU-T Draft Standard Q.2963, Preliminary Draft. International Telecommunication Union, 1995.

....things, we question the value of delegation certificates. 1 Introduction Rivest and Lampson introduced linked local names in Simple Distributed Security Infrastructure (SDSI) This was motivated by the inadequacy of public key infrastructures based on global name hierarchies, such as X. 509 [4] and Privacy Enhanced Mail (PEM) 8] After SDSI version 1.1 [11] the SDSI e#ort merged with the Simple Public Key Infrastructure (SPKI) e#ort. The result is SPKI SDSI 2.0, about which the most up to date document is IETF RFC 2693 [7] The goal of this paper is to study the notion of local ....

ITU-T Rec. X.509 (revised), The Directory - Authentication Framework, International Telecommunication Union, 1993.

....tightened up and extended the definition of Chisel. The result is Cress (Chisel Representation Employing Structured Specifications [18] a feature notation backwards compatible with Chisel, but with a formalised interpretation using Lotos and SDL (Specification and Description Language [9]) Cress starts with even simpler behaviours than Anise: the isolated events that describe communication between a user and the network. These events are then connected using simple constructs such as sequence, guarded choice, iteration and parallel composition. Complex diagrams may be split into ....

ITU. Specification and Description Language. ITU-T Z.100. International Telecommunications Union, Geneva, Switzerland, 1996.

....a formal specification, an implementation under test (IUT) an implementation relation, and a test suite. Preferably there should also be a test generation algorithm which helps to generate test suites automatically. Specifications can be written in a formal language such as SDL [ITU92, ITU95] LOTOS [ISO89] or Estelle [ISO97, Tur93] An implementation is treated as a black box exhibiting behaviour by interacting with its environment. In order to establish a formal relation between specification and implementation, it is assumed that any implementation has a 57 formal model which ....

ITU. SDL combined with ASN.1. ITU-T Z.105. International Telecommunications Union, Geneva, Switzerland, 1995.

....the idea of expressing component (and system) variability in terms of groups of interchangeable modules. Numerous techniques have been proposed for architectural descriptions. Examples include specification languages which support a box and line type block diagram notation, such as ROOM [52] SDL [51,35], and ModeChart [36] architectural description languages such as Aesop [26] Wright [6] UniCon [53] Rapide [43] and ACME [27] and other formal notations such as those used in [49] 31] and [18] All of these techniques refer to the notions of component, connector, and configuration to ....

ITU. CCITT Specification and Description Language, Recommendation Z.100. International Telecommunications Union, 1993.

....the ANISE user. Like several other workers, the author has found LOTOS to be a flexible language that can be used in a wide variety of domains. LOTOS was therefore the language of choice as the formal basis for ANISE. However other languages such as SDL (Specification and Description Language [ITU 96c] would have been possibilities. SDL is much more acceptable to the telecommunications industry. However it would probably be rather harder to use SDL rather than LOTOS to support the constructs described in this paper. A start was therefore made on the translation to LOTOS [TUR 98a] The main ....

ITU, Specification and Description Language, ITU-T Z.100, International Telecommunications Union, Geneva, Switzerland, 1996.

....are those based on formal specification and analysis of feature sets. Many different formal languages have been used to specify features. However, approaches using LOTOS (e.g. BOU 93, FAC 97, KAM 98, ST E 95, THO 97] seem to have been particularly popular. MSCs (Message Sequence Charts [ITU 96b] have also inspired several approaches (e.g. BER 97, BLO 97, DSS 97] AMY 99] proposes an approach for the structuring of features based on use case maps. CHISEL [AHO 98] is another example of a graphically based approach to structuring service specifications. The author has also developed ....

....choice and concurrency. It should therefore be feasible to translate most of ANTEST to other languages. The main difficulty would be in handling concurrency (awkward in SDL, threads in Java) Refusal tests would be expressed by actions that led to an internal error. MSCs (Message Sequence Charts [ITU 96b] could be used as an alternative to ANTEST, thus connecting to a well known formalism. Yet, ANTEST has the advantage of being closed tied in with ANISE (e.g. the use of shorthands for signal names) A graphical approach could also be used with ANTEST. Note that ANTEST merely validates rather ....

ITU, Message Sequence Chart (MSC), ITU-T Z.120, International Telecommunications Union, Geneva, Switzerland, 1996.

....platforms is also restricted. For these reasons, the author set out to extend the CHISEL notation for greater usability, while retaining backwards compatibility with existing diagrams. Diagrams are given formal denotations in two popular formal languages SDL (Specification Description Language [6]) and LOTOS (Language Of Temporal Ordering Specification [5] The end result of this work is an improved language called CRESS (CHISEL Representation Employing Structured Specifications) for graphical feature description, analysis and prototyping. CRESS is supported by a toolset than runs on many ....

....superset of CHISEL, so any CHISEL diagram (subject to disambiguation of syntax) can be processed by the CRESS tools. However CRESS offers a number of simplifications and more tightly defined rules. The grammar of CRESS diagrams has in fact been formulated using the metasyntax used for SDL diagrams [6]. A list of the differences between CHISEL and CRESS is available from the author. Most of the syntactic and static semantic constraints on CRESS diagrams are fairly obvious, but a number of non trivial grammar rules are also enforced. The author has re drawn diagrams from [4] taking advantage ....

ITU. Specification and Description Language. ITU-T Z.100. International Telecommunications Union, Geneva, Switzerland, 1996.

....4 ; G 5 ] B 5 which is particularly non intuitive because the circular symmetry of the network cannot be preserved during the translation to an algebraic term. In this respect, the difficulties inherent to the process algebraic approach have to be compared with graphical formalisms such as SDL [19] or Statecharts [14] in which the user simply has to draw the desired network. For these reasons, we suggested to introduce in E Lotos a new n ary parallel composition operator that would replace the binary operators of Lotos. Based on an early suggestion by [3] we made several iterative ....

ITU-T. Specification and Description Language (SDL). ITU-T Recommendation Z.100, International Telecommunication Union, Gen`eve, 1992.

....foundations of process algebras with language features suitable for a wider industrial dissemination of formal methods. Taking the international standard Lotos as a basis, we suggest several enhancements, which fall into three categories: data part, behaviour part, and modules. Our work was initiated in 1992 in the framework of the Iso Iec Committee for the revision of the Lotos standard. Several of our suggestions have been accepted and will be integrated into the revised standard E Lotos. The other suggestions are considered in the context of Lotos NT, a variant of E Lotos for which a prototype ....

....should be understood that engineers in industry have little time for similar subtleties; they tend to be productive as fast as possible and thus are reluctant to new approaches for reinventing the wheel. In this respect, it is worth noticing that some other languages (e.g. Promela [Hol91] Sdl [IT92] seem to find a faster acceptance. Technically, these languages are often behind process algebras: they lack a formal semantics, they have limitations for expressing concepts such as multi way synchronization, non determinism, internal transitions, etc. Among other reasons, their relative ....

ITU-T. Specification and Description Language (SDL). ITU-T Recommendation Z.100, International Telecommunication Union, Gen`eve, 1992.

....include alternatives and repetitions. A scenario, however, is a specific and bound realisation of a use case, with all choices determined to one specific path. Table 4 shows a number of scenarios identified for the use case normal call. The standardised language of Message Sequence Chart (MSC) (ITU T, 1996; Regnell et al. 1996) may be used to express the structure level of a use case graphically. A High Level Message Sequence Chart (HMSC) is illustrated in Figure 4. Each scenario of the use case normal call is represented as an alternative. Each box with rounded corners refers to either another ....

ITU-T Recommendation Z.120, Message Sequence Chart (MSC), International Telecommunication Union, 1996.

....keys from tickets. Session keys happen to be the first 8 bytes of a ticket, so no complex parsing of the ticket structure is necessary by clients. Communicate with the proxy over some sort of reliable stream. In our implementation, we used a dial in connection and a standard LAPM capable [23] modem, obviating the need for a TCP IP stack on the client. Perform DES encryption and decryption. The DES library is the most complex component of the client side Charon implementation. This is a remarkable statement, given the relative complexity of the full Kerberos protocol and ....

ITU-T Recommendation v.42. International Telecommunication Union, March 93.

....systems communicating by message exchange through shared buffers. In fact, this communication scheme is very suitable for describing distributed systems or communication protocols, and it is the underlying model of popular specification formalisms such as the international standard Sdl [IT92] or the Promela language [Hol91] One of the main difficulties encountered during a compositional generation is to correctly handle the effect of the environment (i.e. the rest of the system) in order to restrict the generation of a given subset of components (otherwise the model obtained for ....

ITU-T. Specification and Description Language (SDL). ITU-T Recommendation Z.100, International Telecommunication Union, Gen`eve, 1992.

....in detail. Our intent is to provide a cost effective working model such that the designer will be able to build on top of it. With the aid of CASE tools for SDL[15,16] one can promptly validate and verify it. This validation can be done by semi automatically generating Message Sequence Charts[17] from the SDL model. As we have shown, the functional requirements of the SDL model reflect the ones from the Use Case Maps, therefore facilitating the task of ensuring correctness. Another possible applications for such a method is the automated generation of test cases[18] Once the UCM model is ....

ITU, Z.120 (1996): Message Sequence Chart (MSC), International Telecommunications Union, Geneva, 1996.

....and security without sacrificing time to market. Some corporations which develop mobile systems and standards are supporting their designers in the use of formal techniques [1,2] such as the ones presented here, namely, Use Case Maps (UCM) 3] and the Specification and Description Language, SDL [4,5]. In this paper, we introduce a method for rapidly converting use case maps into SDL designs. This mapping is done by a designer using our rationale for correctly choosing which SDL structures to derive from UCMs. In Section 2, we introduce both notations, and in section 3 we give some rules for ....

ITU, Z.100 (1996): Specification and Description Language (SDL), International Telecommunications Union, Geneva, 1996.

.... range from adding performance parameters in comments (static annotations) Kritzinger, Wheeler, 1989) Budkowski, 1992) KW89, Bud92] to extending the syntax of the language (Bause, Buchholz, 1990) Diefenbruch, 1994) BB90, D 95] In particular, the semantics of Estelle[ISO89] and SDL(ISO, 1989) ITU94] do not allow the qualitative specification of all the properties necessary to construct an executable model. They provide for the developer to specify timeout values and they acknowledge that delays may occur on channels; however there is no mechanism for the developer to specify the delay ....

....we propose. 2 TIME IN SDL The definition of time in the dynamic semantics of SDL is loose in the sense that it acknowledges that the system will execute in real time with delays on channels, but does not specify how the system execution is affected by this constraint. In particular, SDL assumes (ITU, 1994)[ITU94] ffl time is incremented by a clock outside the system. ffl no units of time are predefined (time may be continuous) ffl signal transfers over channels can take time. ffl an SDL system is not limited by processing resources. This implies that processes may perform SDL actions in zero ....

[Article contains additional citation context not shown here]

ITU-T. Recommendation Z.100 White Book and Annexes. International Telecommunication Union, 1994.

....generated from the m4 templates when SDL PR is produced. The library packages are thus quite human readable. Since GR (SDL Graphical Representation) is often preferred by SDL specifiers, the library templates can also automatically generate comments in the style of CIF (Common Interchange Format [16]) This allows an SDL tool to produce an acceptable graphical representation of the library PR components. The default graphical representation produced by SDL tools when converting PR is often not very readable since graphical layout is a tricky task. Most specifications in this paper are given ....

ITU. Specification and Description Language -- Common Interchange Format. ITU-T Z.106. International Telecommunications Union, Geneva, Switzerland, 1996.

....SDL (Specification and Description Language) Timing Specification 1 Introduction 1.1 Background Digital hardware can be viewed as a concurrent system whose components operate in parallel but synchronised via exchange of electrical signals. Although SDL (Specification and Description Language [15]) was developed for specifying communications systems, it is a general purpose language of wide applicability. It is the contention of this paper that SDL is appropriate and useful for specifying and analysing digital hardware as collections of interacting parallel components. The approach ....

ITU. Specification and Description Language. ITU-T Z.100. International Telecommunications Union, Geneva, Switzerland, 1996.

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ITU, Telemedicine and developing countries, Document 2/116, International Telecommunications Union, 2000.

....ingredients: a formal specification, an implementation under test (IUT) an implementation relation, and a test suite. Preferably there should also be a test generation algorithm which helps to generate test suites automatically. Specifications can be written in a formal language such as SDL [ITU92, ITU95] LOTOS [ISO89] or Estelle [ISO97, Tur93] An implementation is treated as a black box exhibiting behaviour by interacting with its environment. In order to establish a formal relation between specification and implementation, it is assumed that any implementation has a 57 formal model ....

ITU. Guidelines for the Application of ESTELLE, LOTOS and SDL. International Telecommunications Union, Geneva, Switzerland, October 1992.

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ITU. Recommendation X.509, The Directory: Authentication Framework (also ISO/IEC 9594-8, 1995). International Telecommunications Union, Telecommunication Standardization Sector(ITU-T), June 1997.

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ITU. Recommendation z.120: Message sequence chart (MSC). Technical Report Z.120, International Telecommunication Union, 1993.

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ITU, Mozambique unveils leading edge telemedicine facility. International Telecommunication Union. http://www.itu.int/newsarchive/press/releases/1998.

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