Alex Bikfalvi

H-P2PSIP: Interconnection of P2PSIP domains for global multimedia services based on a hierarchical DHT overlay network

The IETF P2PSIP WG is currently standardising a protocol for distributed multimedia services combining the media session functionality of SIP and the decentralised distribution and localisation of resources in peer-to-peer networks. The current P2PSIP scenarios only consider the infrastructure for the connectivity inside a single domain. This paper proposes an extension of the current work to a hierarchical multi-domain scenario: a two level hierarchical peer-to-peer overlay architecture for the interconnection of different P2PSIP domains. The purpose is the creation of a global decentralised multimedia services in enterprises, ISPs or community networks. We present a study of the routing performance and routing state in the particular case of a two-level distributed hash table hierarchy that uses Kademlia. The study is supported by an analytical model and its validation by a peer-to-peer simulator.

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.

Supporting mobility in an IMS-based P2P IPTV service: A proactive context transfer mechanism

In recent years, IPTV has received an increasing amount of interest from the industry, commercial providers and the research community, alike. In this context, standardization bodies, such as ETSI and ITU-T, are specifying the architecture of IPTV systems based on IP multicast. An interesting alternative to support the IPTV service delivery relies on the Peer-to-Peer (P2P) paradigm to distribute and push the streaming effort towards the network edge. However, while P2P IPTV was studied in fixed access technologies, there has been little attention paid to the implications arising in mobile environments. One of these involves the service handover when the user moves to a different network. By analyzing previous work from the perspective of an IPTV service, we concluded that a proactive approach is necessary for the handling of inter-network handovers. In this paper, we propose a new general handover mechanism for the IP Multimedia Subsystem (IMS), while studying its applicability to a P2P IPTV service. Our solution, called proactive context transfer service, incorporates the existing IEEE 802.21 technology in order to minimize the handover delay. The proposal is validated by comparing it against solutions derived from previous work.

Enabling global multimedia distributed services based on hierarchical DHT overlay networks

The provision of innovating multimedia services is a high priority for service providers. Due to the the high traffic volume characteristics of multimedia content, decentralised services are a desired solution for multimedia scenarios. Based on the ongoing work of the IETF P2PSIP WG this paper defines a simple way to interconnect different domains using on peer-to-peer technology. The objective is to provide connectivity between users of different domains and allow decentralised multimedia services to be placed where they can be provided most effectively. Furthermore, the routing performance and routing state is analysed for the proposed hierarchical DHT overlay architecture.

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.

Enabling Global Multimedia Distributed Services Based on Hierarchical DHT Overlay Networks

The provision of innovating multimedia services is a high priority for service providers. Due to the the high traffic volume characteristics of multimedia content, decentralised services are a desired solution for multimedia scenarios. Based on the ongoing work of the IETF P2PSIP WG this paper defines a simple way to interconnect different domains using on peer-to-peer technology. The objective is to provide connectivity between users of different domains and allow decentralised multimedia services to be placed where they can be provided most effectively. Furthermore, the routing performance and routing state is analysed for the proposed hierarchical DHT overlay architecture.

Nozzilla: A Peer-to-Peer IPTV Distribution Service for an IMS-Based NGN

During the last years next generation networks (NGNs) have gained attention, as an increasing number of network operators moved toward triple-play services: telephony, Internet and IPTV. Unfortunately, from the service provider perspective, IPTV usually comes at a high cost in terms of equipment and/or necessary bandwidth. In this paper we propose Nozzilla, a peer-to-peer like video streaming service for an NGN based on the IP Multimedia Subsystem (IMS), which can be used by third-party IPTV service providers as a cost effective alternative to IP multicast or content distribution networks. The service uses the residential gateways (NGN customer premises equipment) to create a streaming overlay using the remaining or a fixed amount of network bandwidth. Nozzilla takes advantage of the QoS and resource reservation enabled by a NGN to support multiple-description streaming that improves the perceived quality during temporary failures.

FLaCoSt: A Novel Peer to Peer Architecture for Video Streaming in a Next Generation Network

This paper proposes a peer-to-peer video streaming delivery system within the framework of Next Generation Networks using Application Level Multicast. Increased efficiency and reliability is achieved in two ways. First, the system uses path diversity by splitting the video traffic in several stripes and distributing each stripe via different multicast trees. Second, the proposed architecture lies within a Next Generation Network framework that enables network resource reservations with different classes of service. Therefore, the video stripes can receive different priorities making possible the usage of Layered Coding techniques such as Multi-Description Coding and Scalable Video Coding. The peer-to-peer protocol takes advantage of the multipath delivery and resources reservation by optimising the searches for a parent in the multicast tree, thus minimising the service access time and service interruptions. These ideas can be improved using always-on central devices like Residential Gateways as peer nodes.