A study of packet losses in the EuQoS network

As Internet usage grows, more efforts are put into analyzing its internal performance, usually such analysis comes through simulation using different models. While simulation can provide a good approximation of network behavior, modeling such a complex network as the Internet is very difficult if not impossible. This paper studies the network’s performance from an experimental point of view using the EuQoS project’s overlay network as a testbed. In the framework of the EuQoS project, many performance tests have been done for proving the reliability of the data transmission. The tests show some rough edges which need further analysis, the most important being random packet losses in UDP flows, and a great amount of out of order packets. This paper focuses on the study of such packet losses, searching for their causes, and more importantly, to show their effects on real-time traffic such as VoIP. As a basis for comparison, the paper also uses TCP traffic to relate the performance of bulk data transfer versus the sustained rate of UDP/RTP flows used for real-time applications. To achieve this goal, several applications are used to generate and capture such traffic and measure its behavior at network level.Peer ReviewedPostprint (author’s final draft

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%.This work has been partially funded by the Grants MEDIANET (S2009/TIC-1466) from the Regional Government of Madrid and CON-PARTE (TEC2007-67966-C03- 03) by the Ministry of Science and Innovation of Spain.Publicad

Programmable overlays via OpenOverlayRouter

Among the different options to instantiate overlays, the Locator/ID Separation Protocol (LISP) [7] has gained significant traction among industry and academia [5], [6], [8]–[11], [14], [15]. Interestingly, LISP offers a standard, inter-domain, and dynamic overlay that enables low capital expenditure (CAPEX) innovation at the network layer [8]. LISP follows a map-and-encap approach where overlay identifiers are mapped to underlay locators. Overlay traffic is encapsulated into locator-based packets and routed through the underlay. LISP leverages a public database to store overlay-to-underlay mappings and on a pull mechanism to retrieve those mappings on demand from the data plane. Therefore, LISP effectively decouples the control and data planes, since control plane policies are pushed to the database rather than to the data plane. Forwarding elements reflect control policies on the data plane by pulling them from the database. In that sense, LISP can be used as an SDN southbound protocol to enable programmable overlay networks [5].Peer ReviewedPostprint (published version

A study of packet losses in the EuQoS network

As Internet usage grows, more efforts are put into analyzing its internal performance, usually such analysis comes through simulation using different models. While simulation can provide a good approximation of network behavior, modeling such a complex network as the Internet is very difficult if not impossible. This paper studies the network’s performance from an experimental point of view using the EuQoS project’s overlay network as a testbed. In the framework of the EuQoS project, many performance tests have been done for proving the reliability of the data transmission. The tests show some rough edges which need further analysis, the most important being random packet losses in UDP flows, and a great amount of out of order packets. This paper focuses on the study of such packet losses, searching for their causes, and more importantly, to show their effects on real-time traffic such as VoIP. As a basis for comparison, the paper also uses TCP traffic to relate the performance of bulk data transfer versus the sustained rate of UDP/RTP flows used for real-time applications. To achieve this goal, several applications are used to generate and capture such traffic and measure its behavior at network level.Peer Reviewe

A study of packet losses in the EuQoS network

As Internet usage grows, more efforts are put into analyzing its internal performance, usually such analysis comes through simulation using different models. While simulation can provide a good approximation of network behavior, modeling such a complex network as the Internet is very difficult if not impossible. This paper studies the network’s performance from an experimental point of view using the EuQoS project’s overlay network as a testbed. In the framework of the EuQoS project, many performance tests have been done for proving the reliability of the data transmission. The tests show some rough edges which need further analysis, the most important being random packet losses in UDP flows, and a great amount of out of order packets. This paper focuses on the study of such packet losses, searching for their causes, and more importantly, to show their effects on real-time traffic such as VoIP. As a basis for comparison, the paper also uses TCP traffic to relate the performance of bulk data transfer versus the sustained rate of UDP/RTP flows used for real-time applications. To achieve this goal, several applications are used to generate and capture such traffic and measure its behavior at network level.Peer Reviewe

Implementing a BGP-free ISP core with LISP

International audienceThe 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

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.Peer ReviewedPostprint (published version

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 offered by the Internet, several companies offer P2P-TV services to their customers. The overwhelming majority of these systems, however, is of closed nature, offering little insight on their traffic properties. For a better understanding of the P2P- TV landscape, we performed measurement experiments in France, Japan, Spain, and Romania, using different commercial applications. By using multiple measurement points in different 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 effect of the traffic 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 traffic 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.Peer ReviewedPostprint (published version

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.Peer Reviewe