Loránd Jakab

LISP-MN: Mobile Networking Through LISP

The current Internet architecture was not designed to easily accommodate mobility because IP addresses are used both to identify and locate hosts. The Locator/Identifier Separation Protocol (LISP) decouples them by considering two types of addresses: EIDs that identify hosts, and RLOCs that identify network attachment points and are used as routing locators. LISP, with such separation in place, can also offer native mobility. LISP-MN is a particular case of LISP which specifies mobility. In this paper we provide a comprehensive tutorial on LISP-MN, showing its main features and how it compares to existing mobility protocols.

Measurement based analysis of the handover in a WLAN MIPv6 scenario

This paper studies the problems related to mobile connectivity on a wireless environment with Mobile IPv6, specially the handover, which is the most critical part. The main goal of this paper is to develop a structured methodology for analyzing 802.11/IPv6/MIPv6 handovers and their impact on applications level. This is accomplished by capturing traffic on a testbed and analyzing it with two applications developed for this purpose. The analysis covers passive and active measurements. This methodology is applicable for measuring improvements on handover (such as Fast Handovers for Mobile IPv6, Hierarchical Mobile IPv6 or 802.11 handover).

Large-scale measurement experiments of P2P-TV systems insights on fairness and locality

P2P-TV is an emerging alternative to classical television broadcast systems. Leveraging possibilities o ered by the Internet, several companies o er P2P-TV services to their customers. The overwhelming majority of these systems however is of closed nature, o ering little insight on their tra c properties. For a better understanding of the P2P-TV landscape, we performed measurement experiments in France, Japan, Spain, and Romania, using di erent commercial applications. By using multiple measurement points in di erent locations of the world, our results can paint a global picture of the measured networks, inferring their main properties. More precisely, we focus on the level of collaboration between peers, their location and the e ect of the tra c on the networks. Our results show that there is no fairness between peers and that is an important issue for the scalability of P2P-TV systems. Moreover, hundreds of Autonomous Systems are involved in the P2P-TV tra c and it points out the lack of locality-aware mechanisms for these systems. The geographic location of peers testifies the wide spread of these applications in Asia and highlights their worldwide usage.

A collaborative P2P scheme for NAT Traversal Server discovery based on topological information

In the current Internet picture more than 70% of the hosts are located behind Network Address Translators (NATs). This is not a problem for the client/server paradigm. However, the Internet has evolved, and nowadays the largest portion of the traffic is due to peer-to-peer (p2p) applications. This scenario presents an important challenge: two hosts behind NATs (NATed hosts) cannot establish direct communications. The easiest way to solve this problem is by using a third entity, called Relay, that forwards the traffic between the NATed hosts. Although many efforts have been devoted to avoid the use of Relays, they are still needed in many situations. Hence, the selection of a suitable Relay becomes critical to many p2p applications. In this paper, we propose the Gradual Proximity Algorithm (GPA): a simple algorithm that guarantees the selection of a topologically close-by Relay. We present a measurement-based analysis, showing that the GPA minimizes both the delay of the relayed communication and the transit traffic generated by the Relay, being a QoS-aware and ISP-friendly solution. Furthermore, the paper presents the Peer-to-Peer NAT Traversal Architecture (P2P-NTA), which is a global, distributed and collaborative solution, based on the GPA. This architecture addresses the Relay discovery/selection problem. We have performed large-scale simulations based on real measurements, which validate our proposal. The results demonstrate that the P2P-NTA performs similarly to direct communications with reasonably large deployments of p2p applications. In fact, only 5% of the communications experience an extra delay that may degrade the QoS due to the use of Relays. Furthermore, the amount of extra transit traffic generated is only 6%. We also show that the P2P-NTA largely outperforms other proposals, where the QoS degradation affects up to more than 50% of the communications, and the extra traffic generated goes beyond 80%.

Evaluation of the fast handover implementation for mobile IPv6 in a real testbed

Fast Handovers is an enhancement to the Mobile IPv6 protocol, currently specified in an IETF draft, which reduces the handover latency. This can be beneficial to real-time applications. This paper presents a novel implementation of Fast Handovers and an analysis of the handover. Using a real testbed we study the handover latency and the provided QoS: analyzing the OWD, IPDV and Packet Loss before and after the handover. Finally we present a comparison between the Mobile IPv6 and the Fast Handovers handover.

Out of order packets analysis on a real network environment

As Internet usage grows, more efforts are put in analysing its internal performance, usually such analysis comes through simulation using different models. While simulation can provide a good approximation of network behaviour, modeling such a complex network as the Internet is very difficult if not impossible. This paper studies the networks performance from an experimental point of view using the European Academic Network (EAN) as a testbed. In the framework of the EuQoS project, many performance tests have been performed to prove the reliability of data transmissions. The tests show some rough edges which need further analysis, among them the most important being random losses in UDP flows and a great amount of out of order packets. This paper focuses on the study of such out of order packets, searching for their causes, and more importantly to show the effects on real-time traffic such as VoIP, videoconferencing, video streaming, etc

CoreCast: How core/edge separation can help improving inter-domain live streaming

The rapid growth of broadband access has popularized multimedia services, which nowadays contribute to a large part of Internet traffic. Among this content, the broadcasting of live events requires streaming from a single source to a large set of users. For such content, network-layer multicast is the most efficient solution, but it has not found wide-spread adoption due to its high deployment cost. As a result, several application-layer solutions have been proposed based on large-scale P2P systems. These solutions however, are unable to provide a satisfactory quality of experience to all users, mainly because of the variability of the peers and their limited upload capacity. In this paper we advocate for a network-layer solution that circumvents the prohibitive deployment costs of previous approaches, taking advantage of the rare window of opportunity offered by the locator/identifier separation protocol (LISP). This new architecture, motivated by the alarming growth rate of the default-free zone (DFZ) routing table, is developed within the IETF, and aims to upgrade the current inter-domain routing system. We present CoreCast, an efficient inter-domain live streaming architecture operating on top of LISP. LISP involves upgrading some Internet routers and our proposal can be introduced along with these new deployments. To evaluate its feasibility in terms of processing overhead in networking equipment we have implemented CoreCast in the Linux kernel. Further, we compare the performance of CoreCast to the popular P2P streaming services both analytically and experimentally. The results show that CoreCast reduces inter-domain bandwidth consumption and that introduces negligible processing overhead in network equipment.

Implementing a BGP-free ISP core with LISP

The sustained growth of the global routing table is exerting an economical strain on ISPs by requiring untimely router upgrades. Notably, it has been speculated that the growth rate of router FIBs is surpassing that of its supporting technology and that the deployment of IPv6 is only to make matters worse. In this paper, we propose LISP-MPS, an architecture based on LISP, that isolates the intra-domain routing of an Autonomous System (AS) from its inter-domain routing. The resulting separation implies the decrease of backbone routing table sizes and enables an AS to control the forwarding of traffic inside its network. For a seamless, cost effective, and incremental deployment, LISP-MPS leverages iBGP to implement the LISP mapping system functionality with minimal modification to a small subset of deployed equipment. Finally, an analysis of realistic topologies shows that, despite changing how packets transit a network, the architecture does not lose resilience to failures. Moreover, we show that it can be a viable alternative to BGP/MPLS deployments due to its low implementation cost.

Measurement Based Call Quality Reporting

Real-time traffic is an important issue when designing networks. The growth in the deployment of voice applications in packet switched networks requires that the network can guarantee a minimum level of quality. At the same time, customers want guaranties that the proper quality of service is provided for their contracted services. In this environment service providers need means of reporting the quality level of their networks. Standardisation bodies define general metrics, such as delay, jitter or losses without giving detailed information regarding the actual users perception of the traffic. Other approaches such as the mean opinion score (MOS), are too coarse to be significant on best-effort based environments such as the Internet. This work is motivated by the potential change in the quality of service (QoS) parameters found in packet switched networks. Which highlights the inaccuracy of metrics such as MOS, since they were designed for the stable circuit switched networks. This paper proposes a novel approach to on-line voice quality measurement which is more suitable for packet switched networks than the classical alternatives, while keeping the subjective approach of MOS. Moreover, our solution permits the real-time reporting of the voice communications quality. Along with the specification of this metric, the paper provides an experimental validation of the proposal using a real testbed with real applications. The results show the higher accuracy in reporting using this proposal over the standard metrics currently used.

Programmable Overlays via OpenOverlayRouter

OpenOverlayRouter (OOR) is an open source software router to deploy programmable overlay networks. OOR leverages the Locator/ID Separation Protocol (LISP) to map overlay identifiers to underlay locators, and to dynamically tunnel overlay traffic through the underlay network. LISP overlay state exchange is complemented with NETCONF remote configuration and VXLANGPE encapsulation. OOR aims to offer a flexible, portable, and extensible overlay solution via a user-space implementation available for multiple platforms (Linux, Android, and OpenWrt). In this article, we describe the OOR software architecture and how it overcomes the challenges associated with a user-space LISP implementation. Furthermore, we present an experimental evaluation of OOR performance in relevant scenarios.