Francisco Valera

P2P vs. IP multicast: Comparing approaches to IPTV streaming based on TV channel popularity

Abstract Already a popular application in the Internet, IPTV is becoming, among the service providers, a preferred alternative to conventional broadcasting technologies. Since many of the existing deployments have been done within the safe harbor of telco-owned networks, IP multicast has been the desired streaming solution. However, previous studies showed that the popularity of the TV channels follows the Pareto principle, with the bulk of TV channels being watched only by a small fraction of viewers. Recognizing the potential scalability issues, we believe that multicast streaming approach may not be desirable for unpopular TV channels, especially when there are many such channels in the provider’s service package. For this reason, the peer-to-peer content distribution paradigm is seen as an alternative, in particular for non-popular content. In order to analyse its viability, in this paper we perform a comparative analysis between IP multicast and a peer-to-peer overlay using unicast connections as streaming approaches, in the context of channels with different degrees of popularity. The analysis targets the bandwidth utilization, video quality and scalability issues, and our findings show that while multicast is always more efficient, peer-to-peer has a comparable performance for unpopular channels with a low number of viewers.

QoS management in fixed broadband residential gateways

QoS management is nowadays a mandatory feature in current broadband residential gateways developments. The interconnection between different QoS domains has to be treated into different steps in order to provide a reliable end-to-end QoS solution. The scenario analyzed in this paper is the mapping between QoS requirements in residential users connected to a broadband access network across a multiservice broadband access gateway. Different approaches to provide QoS in the access network are discussed as well as their impact in the design of a residential gateway. An architecture of a gateway based on IMS (IP Multimedia Subsystem) as SIP-based signaling domain for multimedia services is presented with the corresponding adaptation to a broadband fixed access scenario according to Next Generation Networks (NGN) standardization. Finally, the implementation of a prototype of the QoS-enabled gateway, based on the Click! modular router [1], is described to demonstrate end-to-end QoS provisioning for multimedia services. This prototype allows us the demonstration of (1) an innovative way of extending gateway device functionalities using Click! and (2) the feasibility of residential gateway architecture proposed. The work presented in this paper has been developed within the framework of the 6th Framework Programme IST MUSE [2] project.

Security for multipath TCP: a constructive approach

Multipath TCP (MPTCP) is a new protocol being developed in the IETF|s MPTCP working group in order to provide higher communication availability and to improve the throughput between two multi-addressed endpoints by using multiple paths. Due to the multipath nature and specifically its path management, some new security threats arise apart from those that are already present in standard single-path TCP. These new attacks include flooding and hijacking attacks performed by an off-path attacker. In this paper, we explore different solutions in order to cover the identified security flaws. The main proposal is based on hash chains, which significantly reduces the initial set of threats resulting in a residual group of vulnerabilities, which are also identified.

Adaptive quality of service management for next generation residential gateways

The TISPAN workgroup inside ETSI is currently working on accommodating the IMS (IP Multimedia Subsystem) architecture, which has been created for the mobile world, to the fixed scenario where there is a new important element to be taken into account: the Residential Gateway (RGW). This element is typically considered as a customer device where providers do not usually have anything to configure. However, in order to achieve real end-to-end Quality of Service (QoS) this cannot be true anymore. This paper focuses on the way that a RGW is capable of configuring itself (an interface with the providers is also available), regarding Quality of Service parameters, into a Next Generation Network (NGN) scenario. The proposed RGW architecture is also flexible enough so as to adapt the QoS management mechanism to different possible scenarios, e.g. configured by the provider, by the customer or even autoconfigured by the RGW itself. A specific scenario, where a RGW is deployed in the TISPAN NGN architecture, will be explained and validated to proof the concept of the RGW architecture.

Loop-Freeness in Multipath BGP through Propagating the Longest Path

The concurrent use of multiple paths through a communications network has the potential to provide many benefits, including better utilisation of the network and increased robustness. A key part of a multipath network architecture is the ability for routing protocols to install multiple routes over multiple paths in the routing table. In this paper we propose changes to local BGP processing that allow a BGP router to use multiple paths concurrently without compromising loop-freeness.

Integration of a QoS Aware End User Network within the TISPAN NGN Solutions

The development of specifications for next generation networks has introduced a new network paradigm that has features and capabilities to ensure the provisioning of new value-added multimedia services over the broadband access technologies that are currently being deployed in the market. In this respect, the TISPAN group from ETSI is working in the specification of a next generation network, mainly based on IMS as the service signalling architecture. Nevertheless, the first release of the TISPAN NGN does not consider the QoS provisioning mechanisms in the end user environment. QoS support will necessarily require to extend the QoS scope to the client premises, in order to provide a real end-to-end QoS. In this scenario, the figure of a residential gateway in the user network plays a crucial role. In this paper, an architecture is presented to allow the automatic configuration of the QoS parameters in a residential gateway directly connected to a TISPAN compliant next generation network. This architecture should support the processing of the SIP signalling flows exchanged between the end user environment and the Core IMS in the NGN, deriving relevant information from the SDP payloads and accordingly configuring the QoS parameters in the user network environment

BGP-XM: BGP eXtended Multipath for transit Autonomous Systems

Multipath interdomain routing has been proposed to enable flexible traffic engineering for transit Autonomos Systems (ASes). Yet, there is a lack of solutions providing maximal path diversity and backwards compatibility at the same time. The BGP-XM (Border Gateway Protocol-eXtended Multipath) extension presented in this paper is a complete and flexible approach to solve many of the limitations of previous BGP multipath solutions. ASes can benefit from multipath capabilities starting with a single upgraded router, and without any coordination with other ASes. BGP-XM defines an algorithm to merge into regular BGP updates information from paths which may even traverse different ASes. This algorithm can be combined with different multipath selection algorithms, such as the K-BESTRO (K-Best Route Optimizer) tunable selection algorithm proposed in this paper. A stability analysis and stable policy guidelines are provided. The performance evaluation of BGP-XM, running over an Internet-like topology, shows that high path diversity can be achieved even for limited deployments of the multipath mechanism. Further results for large-scale deployments reveal that the extension is suitable for large deployment since it shows a low impact in the AS path length and in the routing table size.

Four years tracking unrevealed topological changes in the african interdomain

Despite extensive studies on the Internet topology, little is still known about the AS level topology of the African Internet, especially when it comes to its IXP substrate. The main reason for this is the lack of vantage points that are needed to obtain the proper information. From 2013 to 2016, we enhanced the RIPE Atlas measurement infrastructure in the region to shed light on both IPv4 and IPv6 topologies interconnecting local ISPs. We increased the number of vantage points in Africa by 278.3% and carried out measurements between them at random periods. To infer results that depict the behavior of ISPs in the region, we propose reproducible traceroute data analysis techniques suitable for the treatment of any set of similar measurements. We first reveal a large variety of ISP transit habits and their dependence on socio-economic factors. We then compare QoS within African countries, European countries, and the US to find that West African networks in particular need to promote investments in fiber networks and to implement traffic engineering techniques. Our results indicate the remaining dominance of ISPs based outside Africa for the provision of intra-continental paths, but also shed light on traffic localization efforts. We map, in our traceroute data, 62.2% of the IXPs in Africa and infer their respective peers. Finally, we highlight the launch of new IXPs and quantify their impacts on end-to-end connectivity. The study clearly demonstrates that to better assess interdomain routing in a continent, it is necessary to perform measurements from a diversified range of vantage points.

Next-Generation Internet Architectures and Protocols: Multi-path BGP: motivations and solutions

Part of this work has been done within the framework of the Trilogy research and development project. The different research partners of this project are: British Telecom, Deutsche Telekom, NEC Europe, Nokia, Roke Manor Research Limited, Athens University of Economics and Business, University Carlos III of Madrid, University College London, Universit Catholique de Louvain and Stanford University.

Enabling layered video coding for IMS-based IPTV home services

Nowadays IPTV services are gaining attention from both providers and end users. There is a large effort toward the integration of these services into emerging next-generation network architectures. In particular, one of the most relevant solutions is being proposed by ETSI-TISPAN and is based on the IP multimedia subsystem. This article focuses on introducing layered video coding into TISPAN IMS-based IPTV architecture, allowing cost-effective efficient solutions both for residential users and providers (e.g., flexible support of heterogeneous devices, live mosaics, adaptive video quality based on device and/or network capabilities). The advantages of using layered video coding in the TISPAN IPTV solution are analyzed and illustrated with a set of use cases. Furthermore, this solution has been integrated into a multimedia testbed in order to validate the presented proposal.