Boni García

Authentication, Authorization, and Accounting in WebRTC PaaS Infrastructures: The Case of Kurento

WebRTC server infrastructures are useful for creating rich real-time communication (RTC) applications. Developers commonly use them for accessing capabilities such as group communications, archiving, and transcoding. Details on how to implement and use such infrastructures securely are of increasing interest to the engineering community. Kurento is an open source project that provides a WebRTC media server and a platform as a service cloud built on top of it. The authors present the Kurento API and analyze different security models for it, investigating the suitability of using simple access control lists (ACLs) and capability-based security schemes to provide authorization. Using minimal implementation, they discuss the advantages and drawbacks of each scheme and conclude that, for the proposed schemes, ACLs are less scalable but provide more granularity.

WebRTC Testing: Challenges and Practical Solutions

WebRTC comprises a set of novel technologies and standards that provide Real-Time Communication on Web browsers. WebRTC makes simple the embedding of voice and video communications in all types of applications. However, releasing those applications to production is still very challenging due to the complexity of their testing. Validating a WebRTC service requires assessing many functional (e.g. signaling logic, media connectivity, etc.) and non-functional (e.g. quality of experience, interoperability, scalability, etc.) properties on large, complex, distributed and heterogeneous systems that spawn across client devices, networks and cloud infrastructures. In this article, we present a novel methodology and an associated tool for doing it at scale and in an automated way. Our strategy is based on a blackbox end-to-end approach through which we use an automated containerized cloud environment for instrumenting Web browser clients, which benchmark the SUT (system under test), and fake clients, that load it. Through these benchmarks, we obtain, in a reliable and statistically significant way, both network-dependent QoS (Quality of Service) metrics and media-dependent QoE (Quality of Experience) indicators. These are fed, at a second stage, to a number of testing assertions that validate the appropriateness of the functional and non-functional properties of the SUT under controlled and configurable load and fail conditions. To finish, we illustrate our experiences using such tool and methodology in the context of the Kurento open source software project and conclude that they are suitable for validating large and complex WebRTC systems at scale.

Designing and evaluating the usability of an API for real-time multimedia services in the Internet

In the last few years, multimedia technologies in general, and Real-Time multimedia Communications (RTC) in particular, are becoming mainstream among WWW and smartphone developers, who have an increasing interest in richer media capabilities for creating their applications. The engineering literature proposing novel algorithms, protocols and architectures for managing and processing multimedia information is currently overwhelming. However, most of these results do not arrive to applications due to the lack of simple and usable APIs. Interestingly, in this context in which APIs are the critical ingredient for reaching wide developer audiences, the scientific literature about multimedia APIs and their usability is scarce. In this paper we try to contribute to fill this gap by proposing the RTC Media API: a novel type of API designed with the aim of making simple for developers the use of latest trends in RTC multimedia including WebRTC, Video Content Analysis or Augmented Reality. We provide a specification of such API and discuss how it satisfies a set of design requirements including programming-language agnosticism, adaptation to cloud environments, support to multisensory multimedia, etc. After that, we describe an implementation of such an API that has been created in the context of the Kurento open source software project, and present a study evaluating the API usability performed in a group of more than 40 professional developers distributed worldwide. In the light of the obtained results, we conclude that the usability of the API is adequate across the main development activities (i.e. API learning, code creation and code maintenance), with an average usability score of 3.39 over 5 in a Likert scale, and that this result is robust with respect to developers’ profiles, cultures, professional experiences and preferred programming languages.

Kurento: The Swiss Army Knife of WebRTC Media Servers

In this article we introduce Kurento, an open source WebRTC media server and a set of client APIs intended to simplify the development of applications with rich media capabilities for the Web and smartphone platforms. Kurento features include group communications, transcoding, recording, mixing, broadcasting and routing of audiovisual flows, but also provides advanced media processing capabilities such as computer vision and augmented reality. It is based on a modular architecture, which makes it possible for developers to extend and customize its native capabilities with third-party media processing algorithms. Thanks to all of this, Kurento can be a powerful tool for Web developers who may find natural programming with its Java and JavaScript APIs following the traditional three-tiered Web development model.

ElasTest — An open source project for testing distributed applications with failure injection

Testing large complex distributed applications in cloud environments is a complex task. Developing tests to assess these kind of applications is time-consuming, and requires adapting and integrating many different tools for different purposes. The main objective of this demonstration is two-folded. First, it introduces ElasTest, a flexible open source testing platform aimed at simplifying end-to-end testing for different types of applications, allowing developers and testers to assess their cloud applications in a real environment, elastic, and integrated. Second, it demonstrates cloud native application testing on top of the ElasTest platform.

Analysis of Video Quality and End-to-End Latency in WebRTC

WebRTC is a set of emerging technologies that extends the web browsing model to exchange real- time media with other browsers. Despite the fact that WebRTC is still in under development, it is gaining the attention of practitioners quickly. For that reason, the mechanisms to provide quality assurance for WebRTC are key to release these kind of applications to production environments. Nevertheless, testing WebRTC based application, consistently automated fashion is a challenging problem. This article presents the Kurento Testing Framework (KTF), a piece of software aimed to simplify the evaluation activities for WebRTC applications and services. It provides advanced features to carry out complete assessment of WebRTC applications in terms of functionality and quality- of-experience.

Kurento: The WebRTC Modular Media Server

In this paper we introduce Kurento Media Server: an open source WebRTC Media Server providing a toolbox of capabilities which include group communications, recording, routing, transcoding and mixing. Kurento supports a large number of media protocols such as WebRTC, plain RTP, RTSP or HTTP and bunch of codecs including VP8, VP9, H.264, H.263, OPUS, Speex, PCM or AMR. Kurento Media Server is based on a modular architecture, which makes it possible for developers to extend and customize its native capabilities with advanced media processing features such as computer vision, augmented reality or speech analysis. Kurento is ideal for WWW developers who find natural programming with its Java and JavaScript APIs following the traditional three tiered WWW development model.

NUBOMEDIA: An Elastic PaaS Enabling the Convergence of Real-Time and Big Data Multimedia

The increasing acceptance of Network Function Virtualization (NFV) and Software Defined Networks (SDN) paradigms is enabling the creation of cloud technologies combining Real-Time multimedia Communications (RTC) and multimedia processing for big data. Although many vendors already provide solutions in these areas, none of them comprises a single platform for end-to-end service provisioning and deployment addressing all the complexities of combining RTC and media processing. As a result, developing such types of applications is still extremely complex. Following this, we present NUBOMEDIA, an open-source platform enabling developers to create and deploy RTC applications with advanced media processing capabilities. For this, NUBOMEDIA introduces the concept of Media Pipeline: chains of interconnected media processing elements. At deployment time, NUBOMEDIA follows a Platform as a Service (PaaS) scheme, which abstracts for developers most of the complex infrastructure-related tasks such as: provisioning, scaling or QoS and network management. In this paper we present the NUBOMEDIA architecture, which bases on ETSI NFV recommendations, and introduce the main interfaces and capabilities it exposes to developers. To conclude, we present some early experiments demonstrating, through benchmarks, the suitability of the platform to combine RTC and advanced media processing algorithms maintaining the stringent QoS requirements of RTC.

When the testing gets tough, the tough get ElasTest

We present ElasTest, an open-source generic and extensible platform supporting end-to-end testing of large complex cloud systems, including web, mobile, network and WebRTC applications. ElasTest is developed following a fully transparent and open agile process around which a community of developers, contributors and users is collected. We demonstrate ElasTest in action by testing the FullTeachingest application: the video is available from http://elastest.io/videos/icse2018-demo.

User Impersonation as a Service in End-to-End Testing.

Testing large distributed heterogenous systems in cloud environments is a complex task. This situation becomes especially difficult when carrying out end-to-end tests, in which the whole system is exercised, typically through its graphical user interface (GUI) with impersonated users. These tests are typically expensive to write and time consuming to run. This paper contributes to the solution of this problem by proposing an open source framework called ElasTest, which can be seen as an elastic platform to carry out end-to-end testing for different types of applications, including web and mobile. In particular, this piece or research puts the accent on the capability to impersonate final users, presenting a real case study in which end-to-end tests have been carried out to assess the correctness of real-time communications among browsers using WebRTC.