Distributed media server architecture for SIP using IP anycast

Lawful Interception of Voice-over-IP communications is technically more challenging than Lawful Interception in the PSTN. Currently, Lawful Interception for Voice-over-IP traffic is being standardised with respect to VoIP service architectures where central entities are on the signalling path, as this is the way VoIP is being deployed today. However, future types of VoIP service architectures may be characterised by a higher degree of decentralisation. In the extreme case, there is no central entity in the network through which signalling will pass.As an example for such a highly decentralised VoIP system, several proposals have suggested to use a P2P-network for VoIP signalling in conjunction with the Session Initiation Protocol (SIP), commonly referred to as P2PSIP. This paradigm change to P2P-based signalling has significant implications for authorised interception of communications. In this paper, we analyse the problem of applying Lawful Interception to P2P-based Voice-over-IP systems technically, highlighting the characteristic properties of such an approach and the corresponding implications that complicate Lawful Interception. Further, we inspect potential solutions for implementing Lawful Interception in a P2PSIP system in general and discuss advantages and drawbacks of such solutions.KeywordsSession Initiation ProtocolTarget IdentityDistribute Hash TableQuery NodeEnrollment ServerThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

We describe the design, implementation and performance of a stand-alone media server. This server is intended to be used in voice over IP systems for audio interaction with users, NAT traversal, call monitoring and media recording. Its advantage is that it is application independent, which means that it can be used by any service and for any signaling protocol. In this paper we describe the design of the server, of its control protocol and of its functionalities such as file playing, DTMF detection, RTP proxying and audio recording. For file playing, we propose an approach to schedule RTP packet transmission that overcomes the irregularity of event scheduling of the operating system and for conversation recording, we propose an original approach to synchronize media streams that allows to avoid voice overlap while recording a conversation. We have conducted many experiments on the media server. We evaluated the accuracy of the file playing timing under different load conditions, the effect of the RTP proxying on the media quality and the subjective quality of recorded conversations. The results of these experiments show the great impact of the load of the media server on the performance of its functionalities, the improvement that the packet scheduling algorithm brings to the precision of inter-departure timing, and the good subjective quality of the recorded conversation using our synchronizing approach.

In this paper we propose light-weight-agent as an efficient and effective tool for implementing data communication network bandwidth optimization and response time. The routing model for the agents is based on TSP algorithms. Performance comparison was carried out among RPC, Single Mobile Agent and tiny agents otherwise referred to as lightweight agents on the basis of bandwidth usage and response time. The performance evaluation shows the superiority of lightweight agents over the other schemes in terms of bandwidth usage and the response time.

Metro Ethernet is taking off rapidly as a WAN service and the simplicity, ubiquity, and plug-and-play features of Ethernet are some key success factors. The original bridging methods assumed the use of VLANs and spanning tree protocols within provider bridge (PB) and provider backbone bridge (PBB) networks. Because of the inadequacy of the existing spanning tree protocols to support carrier network requirements, very recently, a new class of shortest path routing solutions have been introduced that avoid the use of spanning tree protocols in the core namely, shortest path bridging (SPB). This paper aims at illustrating that we can still use spanning trees in metro ethernet provided that the tree generation and VLAN-spanning-tree mapping are performed adequately. We call our solution smart spanning tree bridging (SSTB). SSTB can be used to enhance the 802.1s MSTP, without requiring significant changes in the current Ethernet equipment. Using very simple but yet realistic numerical examples, we show that SSTB yields near optimal bandwidth and link usage. We also show that SSTB outperforms SPB in terms of service delivery, frame loss and jitter, while being comparable in terms of bandwidth usage and latency. Further, SSTB requires only a couple of spanning tree instances, significantly reducing processing and complexity of bridged networks.

The main objective of this paper is to design and develop a Self-Adaptable Media Service Architecture (SAMSA) for providing reliable dynamic composite multimedia service through policy-based actions. The multimedia services such as media retrieval, transcoding, scaling and display services are combined based on the preferences of the user to create a dynamic composite multimedia service called as Video-on-Demand service. Such distributed multimedia services deployed using Service Oriented Architecture (SOA) can be accessed in heterogeneous environments that are prone to changes during run-time. To provide reliable and adaptive multimedia services, a powerful self-adaptable architecture with dynamic compositions of multimedia services is necessary to adapt during run-time and react to the environment. The adaptability in this proposed architecture is achieved by enabling the service providers to Monitor, Analyze and Act on the defined policies that support customization of compositions of multimedia services and guarantee the Quality of Service (QoS) provisioning. The Media Service Monitor (MSM) observes the business and quality metrics associated with the multimedia services during run-time. The monitored results are analyzed by Monitored Results Analyzer (MRA) which identifies the type and location of the fault. The Adaptive Media Service Manager (AMSM) takes corrective actions based on the monitored results, through the policies defined as an extension of WS-Policy (Web Service--Policy framework). The effectiveness of the proposed Self-Adaptable Media Service Architecture (SAMSA) has been evaluated on Dynamic Composite Real-time Video-on-Demand Web Service (DCRVoDWS) for a maximum of 200 simultaneous client's requests. The analysis of results shows that the proposed architecture provides better improvement on reliability, response time and user satisfaction.

Distributed middleware architectures for scalable media services

Optical Burst Switching (OBS), which works only with optical signal processing, is the next generation hopeful technology for Exabyte optical transport networks. Yet, there are still some issues that need to be addressed such as burst assembling, switching, scheduling, contention resolution and quality of service. Indeed, one of the major problems is to schedule efficiently bursts on wavelength channels without buffers, converters, or other additional equipment. In this paper, we propose the Neural Best Fit Void Filling Scheduler (NBFVFS) for optical burst switching, which is easy to implement using Adjustable MAXNET (AMAXNET) and runs in fixed time. This neural scheduler will contribute to this new emerging solution by providing a parallel, fast, flexible, adaptive, and intelligent process. In comparison with the existing schedulers, the proposed NBFVFS is more efficient both in terms of bandwidth usage as well as in terms of processing speed. NBFVFS gives a new algorithm which will exploit efficiently the existing voids in bandwidth, and thus, reduce loss burst, and better manage data contentions.

This paper presents and analyzes test results of the single rate Three Color Marker (srTCM) algorithm middleware implementation. The srTCM, defined at the RFC 2697, basically performs traffic shaping through two token buckets and packet marking according to their traffic parameters. The test environment evaluates a client-server application performance in terms of bandwidth usage and data throughput when all client requests to the server are intercepted and the server output traffic controlled by the srTCM. The test results allowed a fine-tuning of the stTCM parameter configuration aiming bandwidth allocation fairness and better throughput average to individual data streams.

With the proliferation of multimedia capable devices, media services have to deal with heterogeneous environments where very different types of terminals wish to receive content anywhere and anytime. This situation motivates the appearance of multimedia services that adapt contents to the specific context of users. However, current Internet architecture is based on a rigid layered model, which makes difficult to introduce new functionalities efficiently. To solve this, Service Oriented Architectures (SOA) appear with the goal of proposing new architectures based on services that can be invoked when and where necessary. This work introduces how SOA paradigm can be applied to context-aware multimedia communications. In addition, a scoring function for selecting different service implementations is presented and particularized for a case of selecting transcoding functions taking into account different quality assessment metrics.

It is a common behavior to enrich the automotive driving experience with various media services and applications. However, the effects of this habit are examined mostly from a safety perspective; there is a lack of scientific tools and methods to examine the joint media and driving experience. Therefore, to address Human-Computer Interaction (HCI) while driving from an experience perspective, the model of Mediatized Driver Experiences (MDX) is introduced. It offers a new framework to classify driving and media experiences. In focus are not (only) negative conjunctions (such as distractions), it is rather a holistic approach to the joint experience of the driving and media situation. Therefore, findings from both vehicle safety and communication science were incorporated to develop the MDX model. The model addresses the formation of subjective experiences through influencing factors including the driver as well as the driving, media and social situation. Enjoyment, agency and perceived safety form the subjective experience, hence, the MDX core. Each dimension underlies processes of self-regulation, cognitive processes and affective effects of the driver. The measured core dimensions are then used to classify and aggregate the individual experiences on a higher level.

Our research into multimedia information management and storage focuses on enabling database systems to deal with multimedia content at a high level of abstraction. We examine the database system's role in managing multimedia data. Database systems need to do more than providing a document model or binary large objects to implement multimedia database systems. We examine what the database system's role is in managing multimedia data. We then show how the role of the database system merges with the role of media servers that is an extension of traditional file servers with isochronous multimedia data delivery capabilities. The database system provides richer data management opportunities than media servers because of its increased knowledge of the stored multimedia data. This allows the database system to optimize and better manage system resources and multimedia data delivery.

Existing standard protocols for the web and Internet telephony fail to deliver real-time interactive communication from within a web browser. In particular, the client-server web protocol over reliable TCP is not always suitable for end-to-end low latency media path needed for interactive voice and video communication. To solve this, we compare the available platform options using the existing technologies such as modifying the web programming language and protocol, using an existing web browser plugin, and a separate host resident application that the web browser can talk to. We argue that using a separate application as an adaptor is a promising short term as well as long-term strategy for voice and video communications on the web.

With the rapid success of the Internet and the World Wide Web online access to distributed multimedia data became feasible to experts, but also to regular customers of commercially available Internet- services. At the same time relatively inexpensive and widely available wireless data communication services became available to the mass market. Within the coverage of cellular networks the vision of multimedia information access for “everyone, anytime, anywhere” became reality. This paper describes concept and implementation of MOMENTS (MObile Media and ENTertainment Services) — a complete WWW on-line service for mobile customers. MOMENTS is a joint project of 10 leading European companies. The project is partially funded by the European Union ACTS program. MOMENTS' client- server architecture employs cellular GSM/DCS-1800 telephone networks for data connection. MOMENTS provides several information services specifically designed for mobile lowbandwidth applications, e.g.: automatically adapted third party on-line servicesDetermination of customers geographical location, dynamical provision of location dependent content. Dynamic SMS alert of events to be specified within the service, specifically processed and distributed Video/ Audio material, variety of specific premium services especially designed for the mobile professional Enhanced animation/3D presentation techniques. Additionally, MOMENTS provides a unique micropayment technology which employs the mobile phone SIM card for purse purposes. Charges for services are automatically deducted from this purse. The purse can be “tilled” by on-line withdraw from the customers bank. The MOMENTS- service also provides specific secure authentication capabilities. On clients site the usage of the system within a narrow-bandwidth environment is supported by a number of specifically designed browser plugins. Capabilities of plugins include audio/ video decompression, visualization of vector data and VRML data, acquisition of mobile phone cell information. The complete system was successfully installed and tested on trial sites in Italy, UK, Germany.KeywordsMobile UserMultimedia ServiceContent ProviderService EngineContent FlowThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Librarians and archivists have long understood the professional practice of curation, which includes the practices of collecting, cataloguing, arranging, and assembling for exhibition and display. One of the most important things that libraries do involves developing collections that meet the needs of the people they serve. Professional curation requires a high level of metacognition, because in making selections of what to include and what to omit, a keen awareness of one’s own bias is needed. Public and academic libraries often collect a mix of Hollywood, global, and independent films. But today’s librarians can’t just be good collectors. They must also help learners and patrons develop the curation skills needed to select media for themselves. Effective curation depends on access to reviews and reviewers, and viewers themselves can be empowered to read and provide reviews. Media ratings systems can be both helpful and controversial. Online streaming has changed the way many people use film and video in the home, but there seems to be no established norms for how users access film and media content via library websites. Despite challenges involved in media curation and lingering questions about the impact of streaming collections, librarians can create media collections and services that meet their patrons needs even as the media landscape changes around them.

Web Services is an increasingly used instantiation of Service-Oriented Architectures (SOA) that relies on standard Internet protocols to produce services that are highly interoperable. Other types of services, relying on legacy application layer protocols, however, cannot be composed directly. A promising solution is to implement wrappers to translate between the application layer protocols and the WS protocol. Doing so manually, however, requires a high level of expertise, in the relevant application layer protocols, in low-level network and system programming, and in the Web Service paradigm itself.In this paper, we introduce a generative language based approach for constructing wrappers to facilitate the migration of legacy service functionalities to Web Services. To this end, we have designed the Janus domain-specific language, which provides developers with a high-level way to describe the operations that are required to encapsulate legacy service functionalities. We have successfully used Janus to develop a number of wrappers, including wrappers for IMAP and SMTP servers, for a RTSP-compliant media server and for UPnP service discovery. Preliminary experiments show that Janus-based WS wrappers have performance comparable to manually written wrappers.KeywordsLegacy ServiceRuntime SystemSoap MessageApplication Layer ProtocolWSDL DocumentThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.