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Jonathan Billington - One of the best experts on this subject based on the ideXlab platform.
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symbolic language representations for parametric verification of the revised Capability Exchange signalling protocol
Parallel and Distributed Computing: Applications and Technologies, 2007Co-Authors: Lin Liu, Jonathan BillingtonAbstract:Parametric protocol verification is a challenging r-e- search topic. Obtaining symbolic representations of service and protocol languages of a protocol enables parametric verification of the protocol against its service specification. In this paper, we exploit recurrent structural regularities of state spaces to obtain symbolic representations of protocol languages for the revised Capability Exchange Signalling (CES) protocol. This leads to conjectures on a recursive expression for the revised CES protocol language and for the inclusion of the revised CES protocol language in the CES service language, for any values of the parameters. This result also demonstrates the promising future of our approach to finding symbolic representations for service and/or protocol languages.
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Verification of the Capability Exchange Signalling protocol
International Journal on Software Tools for Technology Transfer, 2007Co-Authors: Jonathan BillingtonAbstract:The Capability Exchange Signalling (CES) protocol is one of the sub-protocols of recommendation H.245, “Control protocol for multimedia communication” issued by the International Telecommunication Union. In this paper, we model the CES protocol with Coloured Petri Nets and verify it using state space and language analyses. The results reveal that the CES protocol could fail when the sequence numbers used by the protocol wrap. To solve this problem, we propose a set of changes to the CES protocol. State space and language analyses are then applied to the revised protocol. Verification results suggest that the revised protocol satisfies the desired properties with the errors discovered being eliminated.
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PDCAT - Symbolic Language Representations for Parametric Verification of the Revised Capability Exchange Signalling Protocol
Eighth International Conference on Parallel and Distributed Computing Applications and Technologies (PDCAT 2007), 2007Co-Authors: Lin Liu, Jonathan BillingtonAbstract:Parametric protocol verification is a challenging r-e- search topic. Obtaining symbolic representations of service and protocol languages of a protocol enables parametric verification of the protocol against its service specification. In this paper, we exploit recurrent structural regularities of state spaces to obtain symbolic representations of protocol languages for the revised Capability Exchange Signalling (CES) protocol. This leads to conjectures on a recursive expression for the revised CES protocol language and for the inclusion of the revised CES protocol language in the CES service language, for any values of the parameters. This result also demonstrates the promising future of our approach to finding symbolic representations for service and/or protocol languages.
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obtaining the service language for h 245 s multimedia Capability Exchange signalling protocol the final step
Conference on Multimedia Modeling, 2004Co-Authors: Lin Liu, Jonathan BillingtonAbstract:The Capability Exchange signalling (CES) protocol is a subprotocol of ITU-T recommendation H.245, "control protocol for multimedia communication". We are interested in verifying this protocol, including verification of its general properties such as absence of deadlocks and livelocks, and verification of the protocol against its service. In previous work, we have analysed the general properties of the CES protocol. In order to verify the protocol against its service, we need to generate the CES service language, which defines all the possible sequences of user observable events. We firstly create the CES service CPN model and then extract the language from the occurrence graph (OG) of the model. In the case of the CES service, this is challenging because we wish to have a general result for arbitrary capacity of the network over which the CES protocol operates. To tackle this problem we introduced into the CPN model a parameter, l, representing the capacity of the communication channel. We derived a recursive formula for the parameterised OG in terms of l. We treat this OG as a finite state automaton (FSA) by nominating acceptance states and apply FSA reduction algorithms to obtain a deterministic FSA that represents the CES service language. We have discovered a recursive formula in l for the CES service language. This paper introduces the CES service via its CPN model as necessary background and presents the final step of the proof of this finding.
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ATVA - Reducing Parametric Automata: A Multimedia Protocol Service Case Study
Automated Technology for Verification and Analysis, 2004Co-Authors: Lin Liu, Jonathan BillingtonAbstract:The Capability Exchange Signalling (CES) protocol is a control protocol for multimedia communications developed by the International Telecommunication Union (ITU) [3]. Our goal is to verify this protocol against the set of allowable sequences of service primitives (i.e. user observable events), known as the service language. Thus the first step to verify the CES protocol is to obtain the CES service language. By using automata reduction techniques [2], our approach is to extract the service language from the Occurrence Graph (OG) of the Coloured Petri Net (CPN) model [4] for the protocol’s service definition. The OG of a CPN model is a directed graph comprising all reachable states (nodes) and state changes (edges) of the model.
Gunnar Hellstrom - One of the best experts on this subject based on the ideXlab platform.
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Indicating source of multi-party Real-time text
2020Co-Authors: Gunnar HellstromAbstract:Real-time text mixers need to identify the source of each transmitted text chunk so that it can be presented in suitable grouping with other text from the same source. An enhancement for RFC 4103 real- time text is provided, suitable for a centralized conference model that enables source identification, for use by text mixers and conference-enabled participants. The mechanism builds on use of the CSRC list in the RTP packet. A Capability Exchange is specified so that it can be verified that a participant can handle the multi-party coded real-time text stream. The Capability is indicated by an sdp media attribute "rtt- mix".
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RTP-mixer formatting of multi-party Real-time text
1999Co-Authors: Gunnar HellstromAbstract:Real-time text mixers for multi-party sessions need to identify the source of each transmitted group of text so that the text can be presented by endpoints in suitable grouping with other text from the same source. Regional regulatory requirements specify provision of real-time text in multi-party calls. RFC 4103 mixer implementations can use traditional RTP functions for source identification, but the mixer source switching performance is limited when using the default transmission characteristics with redundancy. Enhancements for RFC 4103 real-time text mixing is provided in this document, suitable for a centralized conference model that enables source identification and source switching. The intended use is for real-time text mixers and multi-party-aware participant endpoints. The specified mechanism build on the standard use of the CSRC list in the RTP packet for source identification. The method makes use of the same "text/red" format as for two-party sessions. A Capability Exchange is specified so that it can be verified that a participant can handle the multi-party coded real-time text stream. The Capability is indicated by use of a media attribute "rtt-mix-rtp- mixer". The document updates RFC 4103[RFC4103] A specifications of how a mixer can format text for the case when the endpoint is not multi-party aware is also provided.
Lin Liu - One of the best experts on this subject based on the ideXlab platform.
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symbolic language representations for parametric verification of the revised Capability Exchange signalling protocol
Parallel and Distributed Computing: Applications and Technologies, 2007Co-Authors: Lin Liu, Jonathan BillingtonAbstract:Parametric protocol verification is a challenging r-e- search topic. Obtaining symbolic representations of service and protocol languages of a protocol enables parametric verification of the protocol against its service specification. In this paper, we exploit recurrent structural regularities of state spaces to obtain symbolic representations of protocol languages for the revised Capability Exchange Signalling (CES) protocol. This leads to conjectures on a recursive expression for the revised CES protocol language and for the inclusion of the revised CES protocol language in the CES service language, for any values of the parameters. This result also demonstrates the promising future of our approach to finding symbolic representations for service and/or protocol languages.
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PDCAT - Symbolic Language Representations for Parametric Verification of the Revised Capability Exchange Signalling Protocol
Eighth International Conference on Parallel and Distributed Computing Applications and Technologies (PDCAT 2007), 2007Co-Authors: Lin Liu, Jonathan BillingtonAbstract:Parametric protocol verification is a challenging r-e- search topic. Obtaining symbolic representations of service and protocol languages of a protocol enables parametric verification of the protocol against its service specification. In this paper, we exploit recurrent structural regularities of state spaces to obtain symbolic representations of protocol languages for the revised Capability Exchange Signalling (CES) protocol. This leads to conjectures on a recursive expression for the revised CES protocol language and for the inclusion of the revised CES protocol language in the CES service language, for any values of the parameters. This result also demonstrates the promising future of our approach to finding symbolic representations for service and/or protocol languages.
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obtaining the service language for h 245 s multimedia Capability Exchange signalling protocol the final step
Conference on Multimedia Modeling, 2004Co-Authors: Lin Liu, Jonathan BillingtonAbstract:The Capability Exchange signalling (CES) protocol is a subprotocol of ITU-T recommendation H.245, "control protocol for multimedia communication". We are interested in verifying this protocol, including verification of its general properties such as absence of deadlocks and livelocks, and verification of the protocol against its service. In previous work, we have analysed the general properties of the CES protocol. In order to verify the protocol against its service, we need to generate the CES service language, which defines all the possible sequences of user observable events. We firstly create the CES service CPN model and then extract the language from the occurrence graph (OG) of the model. In the case of the CES service, this is challenging because we wish to have a general result for arbitrary capacity of the network over which the CES protocol operates. To tackle this problem we introduced into the CPN model a parameter, l, representing the capacity of the communication channel. We derived a recursive formula for the parameterised OG in terms of l. We treat this OG as a finite state automaton (FSA) by nominating acceptance states and apply FSA reduction algorithms to obtain a deterministic FSA that represents the CES service language. We have discovered a recursive formula in l for the CES service language. This paper introduces the CES service via its CPN model as necessary background and presents the final step of the proof of this finding.
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ATVA - Reducing Parametric Automata: A Multimedia Protocol Service Case Study
Automated Technology for Verification and Analysis, 2004Co-Authors: Lin Liu, Jonathan BillingtonAbstract:The Capability Exchange Signalling (CES) protocol is a control protocol for multimedia communications developed by the International Telecommunication Union (ITU) [3]. Our goal is to verify this protocol against the set of allowable sequences of service primitives (i.e. user observable events), known as the service language. Thus the first step to verify the CES protocol is to obtain the CES service language. By using automata reduction techniques [2], our approach is to extract the service language from the Occurrence Graph (OG) of the Coloured Petri Net (CPN) model [4] for the protocol’s service definition. The OG of a CPN model is a directed graph comprising all reachable states (nodes) and state changes (edges) of the model.
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ICATPN - Tackling the Infinite State Space of a Multimedia Control Protocol Service Specification
Application and Theory of Petri Nets 2002, 2002Co-Authors: Lin Liu, Jonathan BillingtonAbstract:Coloured Petri Nets (CPNs) are used to model the service provided by an International Standard for the control of multimedia communications over telecommunication networks including the Internet, known as the Capability Exchange Signalling (CES) protocol. The state space of the CPN model includes all of the possible sequences of user observable events, known as the service language, which is a useful baseline against which the protocol can be verified. However, the CES service CPN possesses an infinite state space, due to unbounded communication channels. We parameterize the CPN with the channel capacity, propose and prove a recursive formula for its state space and provide an algorithm for its construction. The algorithm generates the state space for capacity l, from the state space for capacity l - 1, providing incremental state space generation rather than generating a new state space for each value of l. The state space is linear in the size of the channel.
Yuting Zhang - One of the best experts on this subject based on the ideXlab platform.
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Mobile terminal Capability management for services enabling
Second International Conference on Wireless and Mobile Communications, ICWMC 2006, 2006Co-Authors: Jun Ma, Chun-dong Wang, Jianxin Liao, Xiaomin Zhu, Yuting ZhangAbstract:The innovation of mobile communications is driving the emergence of new and exciting services. Some killer applications, such as 3 GPP streaming service, need a functionality of mobile terminal Capability Exchange for services enabling, which requires a mechanism to manage terminal capabilities. This paper presents the mobile terminal Capability management (MTCM) architecture allowing to collect, update, store, and provide terminal capabilities dynamically. The proposed architecture leverages open mobile alliance (OMA) Device Management enabler and provides a uniform interface to various service platforms and enabling protocols. The implementation approach of this architecture could be centralized, distributed or mixed. The possible approaches that leverage the Internet Protocol Multimedia Subsystem (IMS) capabilities are also considered.
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Capability Management for Services Enabling 1
2006Co-Authors: Jianxin Liao, Xiaomin Zhu, Chun Wang, Yuting ZhangAbstract:The innovation of mobile communications is driving the emergence of new and exciting services. Some killer applications, such as 3GPP streaming service, need a functionality of mobile terminal Capability Exchange for services enabling, which requires a mechanism to manage terminal capabilities. This paper presents the Mobile Terminal Capability Management (MTCM) architecture allowing to collect, update, store, and provide terminal capabilities dynamically. The proposed architecture leverages Open Mobile Alliance (OMA) Device Management enabler and provides a uniform interface to various service platforms and enabling protocols. The implementation approach of this architecture could be centralized, distributed or mixed. The possible approaches that leverage the Internet Protocol Multimedia Subsystem (IMS) capabilities are also considered.
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ICWMC - Mobile Terminal Capability Management for Services Enabling
2006 International Conference on Wireless and Mobile Communications (ICWMC'06), 2006Co-Authors: Jianxin Liao, Xiaomin Zhu, Chun Wang, Yuting ZhangAbstract:The innovation of mobile communications is driving the emergence of new and exciting services. Some killer applications, such as 3 GPP streaming service, need a functionality of mobile terminal Capability Exchange for services enabling, which requires a mechanism to manage terminal capabilities. This paper presents the mobile terminal Capability management (MTCM) architecture allowing to collect, update, store, and provide terminal capabilities dynamically. The proposed architecture leverages open mobile alliance (OMA) Device Management enabler and provides a uniform interface to various service platforms and enabling protocols. The implementation approach of this architecture could be centralized, distributed or mixed. The possible approaches that leverage the Internet Protocol Multimedia Subsystem (IMS) capabilities are also considered.
Jianxin Liao - One of the best experts on this subject based on the ideXlab platform.
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Mobile terminal Capability management for services enabling
Second International Conference on Wireless and Mobile Communications, ICWMC 2006, 2006Co-Authors: Jun Ma, Chun-dong Wang, Jianxin Liao, Xiaomin Zhu, Yuting ZhangAbstract:The innovation of mobile communications is driving the emergence of new and exciting services. Some killer applications, such as 3 GPP streaming service, need a functionality of mobile terminal Capability Exchange for services enabling, which requires a mechanism to manage terminal capabilities. This paper presents the mobile terminal Capability management (MTCM) architecture allowing to collect, update, store, and provide terminal capabilities dynamically. The proposed architecture leverages open mobile alliance (OMA) Device Management enabler and provides a uniform interface to various service platforms and enabling protocols. The implementation approach of this architecture could be centralized, distributed or mixed. The possible approaches that leverage the Internet Protocol Multimedia Subsystem (IMS) capabilities are also considered.
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Capability Management for Services Enabling 1
2006Co-Authors: Jianxin Liao, Xiaomin Zhu, Chun Wang, Yuting ZhangAbstract:The innovation of mobile communications is driving the emergence of new and exciting services. Some killer applications, such as 3GPP streaming service, need a functionality of mobile terminal Capability Exchange for services enabling, which requires a mechanism to manage terminal capabilities. This paper presents the Mobile Terminal Capability Management (MTCM) architecture allowing to collect, update, store, and provide terminal capabilities dynamically. The proposed architecture leverages Open Mobile Alliance (OMA) Device Management enabler and provides a uniform interface to various service platforms and enabling protocols. The implementation approach of this architecture could be centralized, distributed or mixed. The possible approaches that leverage the Internet Protocol Multimedia Subsystem (IMS) capabilities are also considered.
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ICWMC - Mobile Terminal Capability Management for Services Enabling
2006 International Conference on Wireless and Mobile Communications (ICWMC'06), 2006Co-Authors: Jianxin Liao, Xiaomin Zhu, Chun Wang, Yuting ZhangAbstract:The innovation of mobile communications is driving the emergence of new and exciting services. Some killer applications, such as 3 GPP streaming service, need a functionality of mobile terminal Capability Exchange for services enabling, which requires a mechanism to manage terminal capabilities. This paper presents the mobile terminal Capability management (MTCM) architecture allowing to collect, update, store, and provide terminal capabilities dynamically. The proposed architecture leverages open mobile alliance (OMA) Device Management enabler and provides a uniform interface to various service platforms and enabling protocols. The implementation approach of this architecture could be centralized, distributed or mixed. The possible approaches that leverage the Internet Protocol Multimedia Subsystem (IMS) capabilities are also considered.