Fifth IEEE International Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks最新文献

{"title":"Canet: an object-oriented software package for neitwork design, analysis, and simulation","authors":"A. Kolarov, J. Hui","doi":"10.1109/CAMAD.1994.765638","DOIUrl":"https://doi.org/10.1109/CAMAD.1994.765638","url":null,"abstract":"Recent advances in fiber optics transmission, multi-media services, software technologies, and internetworking methodologies have made the design, management, and analysis of communication networks very complicated. Such complexity requires a more structured view of representing and managing heterogeneity. Subsequently, computer-aided design and simulation tools could be used for real-time design and what-if analysis. A well structured and integrated software, specialized for future integrated services networks, can also be an important experimental tool for understanding these networks. A major contribution of CANeT is the integration of various time-scaled link and .network management functions (design, configuration, routing, flow control, switching, and packet queueing) on a single graphical, optimization, and simulation platform. Such integration is important for the overall network engineering problem. For example, network design is the process of engineering transmission and switching facilities over fairly long time horizon for a wide area network. Network management generally refers to the reconfiguration of network resources to handle hourly or daily variations in the traffic pattern or network topology. Network control very often refers to","PeriodicalId":394638,"journal":{"name":"Fifth IEEE International Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131102123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Form-hmm, a forward-only realtime modified hidden markov modeling algorithm for tracking bursty digital channels","authors":"S. Sivaprakasam, K. Shanmugan","doi":"10.1109/CAMAD.1994.765628","DOIUrl":"https://doi.org/10.1109/CAMAD.1994.765628","url":null,"abstract":"Bursty communication channels can be modeled as hidden Markov sources where the error source is assumed to exist in one of N states and the source alphabet consists of M symbols. In general the Hidden Markov Model (HMM) of a stationary source is given by P, the N x N state.,transition matrix. The N states are partitioned into M sets such that when the source is in a state belonging to set i, symbol i is generated. HMMs provide great flexibility to the design engineer in interpreting the symbols and the states. In general HMM techniques can be an invaluable tool for channel characterization. The problem with existing techniques is that they are computationally intensive and it is usually impossible to use them in real time applications. In many cases, the existing methods also give non unique models since they tend to use either too many or too few parameters in their model structures. Our main contribution is a highly efficient HMM algorithm that can be used in real time channel tracking applications. The method we use integrates our technique for estimating an equivalent (and in a number of cases, unique) model A with the forward-only procedure developed by Narciso Tan et.al. The resulting algorithm is used on an \"improve the model as you go\" basis to provide for real time channel tracking. Using empirical modeling techniques for the channel response, we generate observation sequences and then evaluate the performance of our channel tracking algorithm. The algorithm is being implemented on a C40 based development platform to test its real time applicability.","PeriodicalId":394638,"journal":{"name":"Fifth IEEE International Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130086335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A discrete-time queueing model of an atm 'leaky bucket' policing mechanism.","authors":"F. A. Zanasi, D. Kouvatsos","doi":"10.1109/CAMAD.1994.765663","DOIUrl":"https://doi.org/10.1109/CAMAD.1994.765663","url":null,"abstract":"The International Telephone and Telegraph Consultative Committee (CCITT) have adopted Asynchronous Transfer Mode (ATM) as the transfer technique for future Broadband Integrated Services Digital Networks (B-ISDNs). ATM networks have no node-by-node traffic flow control. However, to protect the quality of service, traffic flow is controlled at the source by 'policing mechanisms'. A policing mechanism ensures that the user doesn't send more traffic onto the network than allowed. The so-called 'leaky bucket' mechanism seems the most favoured of the proposed policing mechanisms. From the point of view of cell loss probabilities (one of the measures of quality of service) the leaky bucket can be modelled exactly as a G/D/1/N queue. The problem with this model is the general arrival pattern of such a queue. Previously proposed models have made large and unrealistic assumptions about the arrival pattern, for example assuming that arrivals are exponentially distributed. This paper proposes the GGeo/GGeo/l/N discrete-time queue solved using the principle of maximum entropy as a much more realistic model. The suitability of this model is twofold. ATM traffic consists of individual cells and is essentially discrete which makes discrate-lime modelling appropriate. Secondly, ATM traffic is very bursty in nature and capturing this burstiness is essential for an accurate model. Moreover the generalised geometric (GGeo) distribution is uniquely described by its first two moments hence the model captures much of the variability of the arrival process caused by this bursty nature. The model is validated using simulation and some numerical results are compared to real data concluding that the model is indeed accurate as well as very computationally efficient.","PeriodicalId":394638,"journal":{"name":"Fifth IEEE International Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130441797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Statistical models for mpeg video standard","authors":"J. Balsells, J. Mata, J. Zarnora, S. Sallent, A. V. D. Kolk","doi":"10.1109/CAMAD.1994.765648","DOIUrl":"https://doi.org/10.1109/CAMAD.1994.765648","url":null,"abstract":"Asynchronous Transfer Mode (ATM) Broadband Networks will support variable bit rate video (VBR) codecs, which are capable of maintaining a constant picture quality of the reconstructed image. The modeling of VBR video source becomes important in the analysis and design of B-ISDN. Network architecture and their characteristics such as cell-loss probabilities, transmission delay, high-speed statistical multiplexing gain, buffering, are strongly related by the statistical properties of the sources and the coding schemes involved. Several video coding schemes have been proposed for VBR services. MPEG is a video coding standard which can be used for transmiting real time variable bit rate broadcast video. WEG has mainly two coding modes: interframe mode and intraframe mode (1). The first one can be distinguished into predicted ones (P) and interpolated ones (B). Coding can be considered on four levels in order of decreasing size: picture, slice, macroblock and block. A picture (or frame) is a basic unit of display. The dimension in pixels of a frame depends on the application. A slice is a horizontal strip within a frame. A macroblock consists of four W blocks of luminance pixels and two W chrominance blocks. 'Me smallest unit is a block which is an W pixels matrix. Using MPEG as a VBR video codec, this work develops and evaluates multistate Markov chain for a three-activity-level (I P, B) as a statistical model to characterize the previous mentioned video standard source.","PeriodicalId":394638,"journal":{"name":"Fifth IEEE International Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121162254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Approximate modeling of multiple priority congestion control in signalling system no. 7","authors":"B. Jabbari, Alpaslan Savas, U. Narayanan","doi":"10.1109/CAMAD.1994.765644","DOIUrl":"https://doi.org/10.1109/CAMAD.1994.765644","url":null,"abstract":"This talk presents analytical and simulation models that attempt to capture the behavior of a structured common channel Signalling System Number 7 network during congestion conditions. In particular, the objective of these models is to study and evaluate the steady state performance of the congestion control protocol operation of Message Transfer Part - level 3 independent of interac tions in the backbone transport network. Therefore, our performance metric deals with messages in contrast to calls. Our analytical model incorporates multiple priority message sources at the signaling points and studies congestion at a single outgoing link of a signaling transfer point. Rea sonable simplifying assumptions are made in order to develop a Markov model to approximate the performance. Two simulation models are also presented to substantiate the assumptions and verify the analytical model. Through the Markov model and simulations we investigate the normalized throughput and blocking probabilities for each of the two priority messages, as well as other mea sures odel, e.g. offered load, buffer onset threshold ratio, ratio of traffic from different priority classes, and timers are varied. We also compare the multiple priority congestion control scheme with the no-priority case. In addition, by using the second set of simulations, we show that the basic timer of the congestion control mechanism, though a deterministic value in real implementa tion, may be approximated to obey an exponential interarrival distribution without causing major errors. These simulations also show that the mean interarrival time between the expirations of this timer is a function of the offered load, and becomes essentially constant after a critical value of the offered load is exceeded. Since the behavior of this timer is critical to the imbedded Markov chain analysis, where the process is observed after each departure epoch, formulation of the imbedded Ma;rkov chain then becomes possible.","PeriodicalId":394638,"journal":{"name":"Fifth IEEE International Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132574208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comtron: a tool for the simulation of communication systems","authors":"G. Benel, L. Favalli, A. Mecocci, G. Monteleone","doi":"10.1109/CAMAD.1994.765674","DOIUrl":"https://doi.org/10.1109/CAMAD.1994.765674","url":null,"abstract":"The simulation of communication systems is of fundamental importance for engineering and economical purposes, Authe moment there am many tools that can simulate many aspects of communication systems but their use is often very complex. In this work a relatively simple metalanguage is described, which is particularly suited for the simulation of this kind of systems. The structure of this language is essentially' descriptive and not procedural. The user describes the colmuruication @ystcrri defining first of all a sequence of blocks. The user's file. then, is sent to a parser using a clasisical.Top-down predictive parsing algorithm that provides some additional features to avoid recursion since it is intended for use on PC type HW platforms which exhibit relative, limitations in stack allocation. The fundamental data processing unit is the block, which is seen as a black-box with an input and an output poM to insert and extract data. The functionalities performed by the blocks am of different kinds. ~ The source block, is used to create a data flow representing a message to be tted with a given probability. ~ The coder block receives in input a bit stream (the message) and performs some block code or convolutional code manipulation. The output of the block is the coded message. ~ The modulator block presents some -additional difficulties since in the real world output of a modulator is an analog signal. In our tool this signal is sampled at the appropriate frequency fixed in agmement with the Nyquist's rale.","PeriodicalId":394638,"journal":{"name":"Fifth IEEE International Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133496425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cossap stream driven simulator integration with AT&T DSP1610 LFS","authors":"K. Allsop","doi":"10.1109/CAMAD.1994.765673","DOIUrl":"https://doi.org/10.1109/CAMAD.1994.765673","url":null,"abstract":"COSSAP is a stream driven simulation engine supported by a graphical signal flow graph design entry methodology. The system is delivered with over 800 simulation models, from basic to advanced functions, and user models written in C or Fortran can be easily integrated into the simulation. If a VHDL simulator is available then models in VHDL can be co-simulated with COSSAP. These tools have been used extensively in the design of communication systems. The COSSAP stream driven simulator, because of its inherent data flow structure, is readily integrated with other simulators. Here an integration with the AT&T DSPI610 Linkable Functional Simulator (LFS) is demonstrated. The LFS is a system design tool for the AT&T DSPI610 fixed point DSP. This s stem affords the designer the capability to investigate system partitioning tr ade-offs, y and observe the effects of finite word length arithmetic in the DSP. These mixed level simulations are achieved while working within a single consistent user interface. The consistent user interface minimises the learning curve across the simulation tool set, enabling a high level of productivity to be maintained. A typical design flow might be to investigate the system concept using floating point models, and to iterate the design until the most promising solution is found . At this stage the models can now be migrated to fixed point representation and finite word length effects investigated, and finally the fixed point models translated into code to run on the fixed point DSP. This whole process can be interated until the desired performance is achieved within the overall system constraints. Further, with the mixed level simulation capability the algorithm may be segmented across floating point, fixed point and DSP code implementations as necessary.","PeriodicalId":394638,"journal":{"name":"Fifth IEEE International Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116737002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On mixture densities in importance sampling","authors":"J. S. Stadler, Sumit Roy, Ping Zhang","doi":"10.1109/CAMAD.1994.765631","DOIUrl":"https://doi.org/10.1109/CAMAD.1994.765631","url":null,"abstract":"E c SM ( M large), f (n ) = c,e-A4(n), and X > 0 usually represents a physically meaningful parameter (such as signal-to-noise ratio (SNR) or number of servers in the network, depending on the context) that we will consider to be asymptotically large. Direct Monte Carlo evaluation of (1) is well-known to be inefficient, and Importance Sampling (IS) has established itself as an attractive alternative [l, 41. The Importance Sampling (IS) estimator for ( I ) is","PeriodicalId":394638,"journal":{"name":"Fifth IEEE International Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115381666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-speed networks of the future some research issues to be addressed","authors":"M. Schwartz","doi":"10.1109/CAMAD.1994.765659","DOIUrl":"https://doi.org/10.1109/CAMAD.1994.765659","url":null,"abstract":"In this talk we discuss the ATM-based high speed networks of the future and multimedia applications expected to be distributed over them. Included among the bandwidth -intensive traffic to be handled are video and high-resolution .,. images. Characterization of this traffic is necessary to ensure network control and appropriate traffic quality-of-service (OOS) are mentioned. These networks will be required to interface with much lower bandwidth wireless networks. This talk focuses on a number of research issues that must be addressed to have network users experience \"seamless communication\" end to-end. These include the design of multimedia multipoint communication protocols as well as issues of network management and control.","PeriodicalId":394638,"journal":{"name":"Fifth IEEE International Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121500393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Error performance of atm networks","authors":"M. Noorchashm, W. Turin","doi":"10.1109/CAMAD.1994.765664","DOIUrl":"https://doi.org/10.1109/CAMAD.1994.765664","url":null,"abstract":"In this paper, we describe the calculation of the performance parameters of a point-to-point ATM connection transported on an STS-3c SONET (SDH STM-1) interface on the basis of the physical layer model derived from experimental data. An estimate for Cell Error Ratio (CER) was presented Wil] based on the objectives specified in the draft Recommendation G.82X,21 for Constant Bit Rate (CBR) channels. The general question of error performance in ATM layer is revisited here and parameters defined in draft Recommendation 1.3513131 including CER are calculated. 'Mese parameters are Cell Error Ratio (CER), Cell Loss Ratio (CLR), and Severely Errored Cell Block Ratio (SECBR). Statistics of consecutive errored and lost cells are likewise calculated for each run of the simulation. The physical layer performance parameters such as Bit Error Ratio (BER), Errored Second Ratio (ESR), and Severely Errored Second Ratio (SESR) are also calculated for comparison with corresponding objective values for CBR channels. In order to estimate the values of these parameters, an accurate characterization of the underlying physical layer is necessary. This characterization should be based on the behavior of the real channels in digital networks and satisfy the objective values indicated in the standards. [31 The bursty nature of errors in the physical layer is described by the Mdden Markov Model (HMM) [41 151 [61 171181191 the parameters of which are estimated using experimental data. The importance of using this model is demonstrated by the results presented in this paper: the ATM performance for channels with independent errors differs significantly from the ATM performance for channels with bursts of errors and equal bit error ratios. The performance parameters are evaluated both analytically and using computer simulation. The simulation program and analytical expressions that we have developed can be used to investigate the critical values of the parameters of the model in a top-down fashion. Simulation results can also be used to determine bounds on the objective values for the performance parameters of the ATM layer. Extensions of the simulation provide insight into the requirements of the physical layer, the ATM layer, and the layers using the services of the ATM layer, to achieve desired quality of service for applications using the ATM network. In our calculations, losses due to policing and congestion control are not included. Cell loss calculated here is only due to errored bits in the ATM cell headers. Severely Errored Cell Blocks are excluded ftom calculation of CER and CLR as required by 1.35B. Block size is assumed to be equal to an STS-3c SONET frame. Simulation results show that CER values are several orders of magnitude higher for the simulation runs using channels with independent error bits than for the channels with bursts of errors. The scattered error bits contribute to the total count of errored cells in the case of channels with independent error bit","PeriodicalId":394638,"journal":{"name":"Fifth IEEE International Workshop on Computer-Aided Modeling, Analysis, and Design of Communication Links and Networks","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134521653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}