Isaias Martinez-Yelmo

Routing Performance in a Hierarchical DHT-based Overlay Network

The scalability properties of DHT based overlay networks is considered satisfactory. However, in large scale systems this might still cause a problem since they have a logarithmic complexity depending. Further, they only provide a one dimensional structure and do not make use on inherent clustering properties of some applications (e.g. P2PVoIP or locality aware overlays). Thus, structures based on a hierarchical approach can have performance as well as structural advantages. In this paper, a generic hierarchical architecture based on super-peers is presented where a peer ID is composed by a prefix ID and a suffix ID. Prefix ID is only routed at the super-peer level and the Suffix ID at the peer level. We specifically analyse the Routing Performance of this approach within the context of two specific overlays, viz. CAN and Kademlia.

Multicast traffic aggregation in MPLS-based VPN networks

This article gives an overview of the current practical approaches under study for a scalable implementation of multicast in layer 2 and 3 VPNs over an IP-MPLS multiservice network. These proposals are based on a well-known technique: the aggregation of traffic into shared trees to manage the forwarding state vs. bandwidth saving trade-off. This sort of traffic engineering mechanism requires methods to estimate the resources needed to set up a multicast shared tree for a set of VPNs. The methodology proposed in this article consists of studying the effect of aggregation obtained by random shared tree allocation on a reference model of a representative network scenario.

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.

Fair quality of experience (qoe) measurements related with networking technologies

This paper addresses the topic of Fair QoE measurements in networking. The research of new solutions in networking is oriented to improve the user experience. Any application or service can be improved and the deployment of new solutions is mandatory to get the user satisfaction. However, different solutions exist; thus, it is necessary to select the most suitable ones. Nevertheless, this selection is difficult to make since the QoE is subjective and the comparison among different technologies is not trivial. The aim of this paper is to give an overview on how to perform fair QoE measurements to facilitate the study and research of new networking solutions and paradigms. However, previously to address this problem, an overview about how networking affects to the QoE is provided.

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.

A simulation-based study of TCP performance over an optical burst switched backbone with 802.11 access

The combined effect of optical and wireless subnetworks in an hypothetical future scenario where core networks have evolved to the still prototype Optical Burst Switching (OBS) technology is an open research issue. n nThis paper studies this hybrid scenario, in the particular case of 802.11 access, by reviewing the key aspects of OBS and 802.11 with an impact on the performance of TCP, and makes a simulation-based assessment of the relative influence of both technologies over the effective end-to-end behaviour of TCP.

A Hierarchical P2PSIP Architecture to Support Skype-like Services

A hierarchical DHT overlay architecture based on P2PSIP is proposed to support a skype-like service. The IETF P2PSIP working group is standardizing a protocol to support any DHT in order to deploy services inside a domain. We extend its functionality to allow the interaction between peers of different domains. Furthermore, we perform an analysis of the routing performance and resource consumption under a skype-like scenario where VoIP calls are more likely to happen among users of the same domain.

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.

Bittella: a novel content distribution overlay based on bittorrent and social groups

This paper presents Bittella: a newsocial network for content distribution based on Peer-to-Peer technologies. It exploits the common interests of the users in order to create social groups based on an algorithm called Ranking Algorithm. On the other hand, Bittella is deployed over a semantic-search based and unstructured p2p network, in spite of this it uses Bittorrent-like download techniques in order to improve the download time. For this purpose, a new Bittorrent trackerless scheme is proposed.

Always best (dis-)connected: challenges to interconnect highly heterogeneous networks

Wireless networks enable mobility, multihoming, and Delay Tolerant Networks. In such networking environments, the principles of the Internet, i.e., the end-to-end principle and the combination of location and identification in IP addresses, cannot be applied. In this paper, we propose a scalable application centric approach for mobility and multihoming that is able to interconnect highly heterogeneous networks where the networks may belong to different networking paradigms, e.g., IP based and Delay Tolerant Networks. Applications and users that aim to communicate, form communities. Community members might together have several network technologies available, and the community layer manages internetworking information for the members to seamlessly integrate these. Networking adaptation layers are used to provide a common interface for the different networks to the community layer. Addressing is based on names, cryptographic identifiers, and network locators and such that identifiers can also be created in infrastructure-less and disconnected situations.