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 mul- timedia 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.En prens

IMS signalling for multiparty services based on network level multicast

3rd EURO-NGI Conference on Next Generation Internet Networks. Norwegian University of Science and Technology, Trondheim, Norway, 21-23 may 2007.The standardization process of the UMTS technology has led to the development of the IP Multimedia Subsystem (IMS). IMS provides a framework that supports the negotiation of the next generation multimedia services with QoS requirements that are envisioned for 3G networks. But even though many of these services involve the participation of multiple users in a multiparty arrangement, the delivery technology at network level is still unicast based. This approach is not optimum, in terms of transmission efficiency. In this paper, a new approach is presented proposing to use a network level multicast delivery technology for the multiparty services that are signalled through IMS. The main advantages and drawbacks related with this new approach are analyzed in the article. Finally, as a starting point in the development of the presented solution, a new SIP signalling dialogue is proposed allowing the negotiation of a generic multiparty service, and supporting at the same time the configuration of the corresponding network level multicast delivery service with QoS requirements that will be used in the user plane.Publicad

Scalable data replication in content-centric networking based on alias names

Content-Centric Networking (CCN) is a clean-slate proposal to redesign the current Internet by focusing on the content itself, instead of the classical computer-to-computer communication. In this paper we address scalability issues of the Forwarding Information Base (FIB) in CCN. Our solution proposes both the use of hierarchical names assigned by access providers and a novel alias name architecture. With the former, we allow the aggregation of entries at the routing tables of CCN content routers, while the latter reduces the processing load at those routers when replicas exist in different parts of the network. With some minor changes to the original proposal, we provide a scalable solution for data replication in CCN, which inherently supports content mobility at the same time. We validate our scheme by (1) comparing the scalability of CCN against our proposal and by (2) implementing and testing a proof-of-concept software based on CCNx, to prove the viability of this approach.This article has been partially supported by the Spanish Ministry of Economy and Competitiveness (MINECO) by means of the project MASSES (TEC2012-35443) and by the Comunidad de Madrid E-Madrid (S2009/TIC-1650) project

On the effect of sudden data bursts in the upstream channel of Ethernet PONs employing IPACT under the gated-service discipline

The Interleaved Polling with Adapted Cycle Times (IPACT) algorithm for dynamic bandwidth allocation proposed for Ethernet Passive Optical Networks (EPONs) has been deeply analysed in the literature under Poisson traffic. However, the case when ONUs suddenly offer bursty traffic in the upstream channel of a PON has not been considered in such detail.This paper studies the performance behaviour of the upstream channel of EPONs employing IPACT with the gated-service disciple, under Poisson traffic together with sudden bursts. We show that one burst arrival produces a peak in the average transmission window of every ONU, lasting its effects for several cycle times, depending on the burst size and the average network load. Such a burst has a direct impact on the delay experienced by the packets of other ONUs. This is mathematically modelled using a modification of the formerly studied M/G/1 queue with vacations and validated with simulation.The authors would like to thank the reviewers for their valuable comments through the reviewing process of this paper. The authors would also like to acknowledge the Spanish-funded CRAMnet (Grant no. TEC2012-38362-C03-01) and the Madrid Community MEDIANET (S2009-TIC1468) projects for their support to this work

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

Evaluating Extensions to IMS Session Setup for Multicast-based Many-to-Many Services

Telecommunication networks are converging towards an all-IP paradigm that integrates a broad set of value-added services. In this context, the IP Multimedia Subsystem (IMS) is being developed by the 3GPP as a key element to achieve the convergence. Additionally, multiparty services are nowadays acquiring an increasing interest from the industry. In this respect, network multicast provides a cost-effective solution to deliver these services to the user. Nevertheless, although network multicast is being considered as an enabler for one-to-many services (e.g. IPTV) in the IMS, the specifications for many-to-many services still follow a unicast approach (e.g. push-to-talk and conference). This paper describes extensions to the session control procedures in the IMS, to support multicast based multi-user services. The idea was first described in a prior work, but this paper presents enhancements to provide a comprehensive solution and to improve the grade of service (GOS) perceived by the users. In addition, the GOS achieved by the proposal is evaluated. First, the bandwidth utilization for the multicast-based multi-user services is analyzed and compared against the unicast scenario. Next, the GOS is evaluated using an analytical approach, by obtaining the mathematical expressions for the session and user plane setup delays. Finally, the GOS is also evaluated using an experimental approach, and the results are compared with values recommended by the ITU-T

Analysis of scaling policies for NFV providing 5G/6G reliability levels with fallible servers

The softwarization of mobile networks enables an efficient use of resources, by dynamically scaling and re-assigning them following variations in demand. Given that the activation of additional servers is not immediate, scaling up resources should anticipate traffic demands to prevent service disruption. At the same time, the activation of more servers than strictly necessary results in a waste of resources, and thus should be avoided. Given the stringent reliability requirements of 5G applications (up to 6 nines) and the fallible nature of servers, finding the right trade-off between efficiency and service disruption is particularly critical. In this paper, we analyze a generic auto-scaling mechanism for communication services, used to de(activate) servers in a cluster, based on occupation thresholds. We model the impact of the activation delay and the finite lifetime of the servers on performance, in terms of power consumption and failure probability. Based on this model, we derive an algorithm to optimally configure the thresholds. Simulation results confirm the accuracy of the model both under synthetic and realistic traffic patterns as well as the effectiveness of the configuration algorithm. We also provide some insights on the best strategy to support an energy-efficient highly-reliable service: deploying a few powerful and reliable machines versus deploying many machines, but less powerful and reliable.The work of Jorge Ortin was funded in part by the Spanish Ministry of Science under Grant RTI2018-099063-B-I00, in part by the Gobierno de Aragon through Research Group under Grant T31_20R, in part by the European Social Fund (ESF), and in part by Centro Universitario de la Defensa under Grant CUD-2021_11. The work of Pablo Serrano was partly funded by the European Commission (EC) through the H2020 project Hexa-X (Grant Agreement no. 101015956), and in part by Spanish State Research Agency (TRUE5G project, PID2019-108713RB-C52PID2019-108713RB-C52/AEI/ 10.13039/501100011033). The work of Jaime Garcia-Reinoso was partially supported by the EC in the framework of H2020-EU.2.1.1. 5G EVE project (Grant agreement no. 815074). The work of Albert Banchs was partially supported by the EC in the framework of H2020-EU.2.1.1. 5G-TOURS project (Grant agreement no. 856950) also partially supported by the Spanish State Research Agency (TRUE5G project, PID2019-108713RB-C52PID2019- 108713RB-C52/AEI/10.13039/501100011033)

TRIM: An architecture for transparent IMS-based mobility

In recent years, the development and deployment of new wired and wireless access net work technologies have made the ubiquitous Internet a reality. Users can access anywhere and anytime to the broad set of value added Internet services, which are delivered by means of the IP protocol. In this context, 3GPP is currently developing the IP Multimedia Subsystem (IMS), as a key element that allows to evolve from the ubiquitous access to the Internet services towards a next generation network model, by providing a set of essen tial facilities such as session control, QoS, charging and service integration. Nevertheless, several open issues still need consideration before the future Internet becomes real, such as supporting user mobility in IP networks. Although mobility support in the Internet is receiving much attention, IMS networks present inherent particularities that require fur ther analysis. The solutions proposed so far for IMS do not support mobility transparently to the end user applications, or address the problem by introducing complex changes to the IMS infrastructure. This paper presents TRIM, an architecture for transparent IMS based mobility. TRIM supports mobility in IMS networks transparently to the end user applications, which are unaware of the handover management procedures executed between the mobile node and the network. We have performed several experiments with a TRIM prototype, using a real IMS testbed with 3G and WLAN access networks, validating the proposal for UDP and TCP based applications.European Community's Seventh Framework ProgramPartially granted by the Madrid Community through the MEDIANET project (S 2009/TIC 1468)Publicad

A solution for transparent mobility with route optimization in the IP multimedia subsystem

This paper presents TRIM+, an architecture for transparent mobility management with route optimization in IMS based networks. The design of our architecture is based on a previous work referred to as TRIM. TRIM was originally devised to provide transparent mobility support in the IMS, although transparency came at the cost of using a suboptimal data path between communicating end points. TRIM+ maintains transparency as a design criterium, and thus end-user applications, running at the mobile node and its correspondent communication peers, are unaware of mobility management procedures. Additionally, the proposed design defines a set of route optimization procedures, allowing compliant devices to use the optimal data path for media communications. Furthermore, TRIM+ addresses packet loss management in scenarios where the media path cannot be maintained during the handover of the MN. To this end, our architecture enables the MN to request buffering capacity in its home network to temporarily store incoming media traffic during the handover, which would otherwise be dropped. This mechanism, as well as route optimization procedures, are executed transparently to the end-user applications running at the communicating end points. As a proof-of-concept, we have implemented a software prototype of the TRIM+ architecture, deploying it over a real IMS testbed. By means of a set of experiments, we have validated the mechanisms proposed in this paper, considering both UDP and TCP user traffic.This article has been partially granted by the Madrid Commu nity through the MEDIANET project (S 2009/TIC 1468), and by the European Community through the CROWD project (FP7 ICT 318115). The work of Ignacio Soto has been partially sup ported through the I MOVING project (TEC2010 18907).Publicad

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

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.This article has been partially supported by the Spanish Ministry of Science and Innovation through the CONPARTE project (TEC2007-67966-C03-03/TCM), and by the Madrid Community through the MEDIANET project (S2009- TIC1468)Publicad