87 research outputs found
How long delays impact TCP performance for a connectivity from Reunion Island ?
TCP is the protocol of transport the most used in the Internet and have a
heavy-dependence on delay. Reunion Island have a specific Internet connection,
based on main links to France, located 10.000 km away. As a result, the minimal
delay between Reunion Island and France is around 180 ms. In this paper, we
will study TCP traces collected in Reunion Island University. The goal is to
determine the metrics to study the impacts of long delays on TCP performance
Where is My Next Hop ? The Case of Indian Ocean Islands
Internet has become a foundation of our modern society. However, all regions
or countries do not have the same Internet access regarding quality especially
in the Indian Ocean Area (IOA). To improve this quality it is important to have
a deep knowledge of the Internet physical and logical topology and associated
performance. However, these knowledges are not shared by Internet service
providers. In this paper, we describe a large scale measurement study in which
we deploy probes in different IOA countries, we generate network traces,
develop a tool to extract useful information and analyze these information. We
show that most of the IOA traffic exits through one point even if there exists
multiple exit points
A Multifaceted Look at Starlink Performance
In recent years, Low-Earth Orbit (LEO) mega-constellations have emerged as a
promising network technology and have ushered in a new era for democratizing
Internet access. The Starlink network from SpaceX stands out as the only
consumer-facing LEO network with over 2M+ customers and more than 4000
operational satellites. In this paper, we conduct the first-of-its-kind
extensive multi-faceted analysis of Starlink network performance leveraging
several measurement sources. First, based on 19.2M crowdsourced M-Lab speed
test measurements from 34 countries since 2021, we analyze Starlink global
performance relative to terrestrial cellular networks. Second, we examine
Starlink's ability to support real-time web-based latency and
bandwidth-critical applications by analyzing the performance of (i) Zoom video
conferencing, and (ii) Luna cloud gaming, comparing it to 5G and terrestrial
fiber. Third, we orchestrate targeted measurements from Starlink-enabled RIPE
Atlas probes to shed light on the last-mile Starlink access and other factors
affecting its performance globally. Finally, we conduct controlled experiments
from Starlink dishes in two countries and analyze the impact of globally
synchronized "15-second reconfiguration intervals" of the links that cause
substantial latency and throughput variations. Our unique analysis provides
revealing insights on global Starlink functionality and paints the most
comprehensive picture of the LEO network's operation to date.Comment: In submissio
Methods for revealing and reshaping the African Internet Ecosystem as a case study for developing regions: from isolated networks to a connected continent
Mención Internacional en el título de doctorWhile connecting end-users worldwide, the Internet increasingly promotes local development
by making challenges much simpler to overcome, regardless of the field in which it is
used: governance, economy, education, health, etc. However, African Network Information Centre
(AfriNIC), the Regional Internet Registry (RIR) of Africa, is characterized by the lowest Internet
penetration: 28.6% as of March 2017 compared to an average of 49.7% worldwide according
to the International Telecommunication Union (ITU) estimates [139]. Moreover, end-users experience
a poor Quality of Service (QoS) provided at high costs. It is thus of interest to enlarge the
Internet footprint in such under-connected regions and determine where the situation can be improved.
Along these lines, this doctoral thesis thoroughly inspects, using both active and passive
data analysis, the critical aspects of the African Internet ecosystem and outlines the milestones of
a methodology that could be adopted for achieving similar purposes in other developing regions.
The thesis first presents our efforts to help build measurements infrastructures for alleviating
the shortage of a diversified range of Vantage Points (VPs) in the region, as we cannot improve
what we can not measure. It then unveils our timely and longitudinal inspection of the
African interdomain routing using the enhanced RIPE Atlas measurements infrastructure for filling
the lack of knowledge of both IPv4 and IPv6 topologies interconnecting local Internet Service
Providers (ISPs). It notably proposes reproducible data analysis techniques suitable for the treatment
of any set of similar measurements to infer the behavior of ISPs in the region. The results
show a large variety of transit habits, which depend on socio-economic factors such as the language,
the currency area, or the geographic location of the country in which the ISP operates.
They indicate the prevailing dominance of ISPs based outside Africa for the provision of intracontinental
paths, but also shed light on the efforts of stakeholders for traffic localization.
Next, the thesis investigates the causes and impacts of congestion in the African IXP substrate,
as the prevalence of this endemic phenomenon in local Internet markets may hinder their
growth. Towards this end, Ark monitors were deployed at six strategically selected local Internet
eXchange Points (IXPs) and used for collecting Time-Sequence Latency Probes (TSLP) measurements
during a whole year. The analysis of these datasets reveals no evidence of widespread
congestion: only 2.2% of the monitored links experienced noticeable indication of congestion,
thus promoting peering. The causes of these events were identified during IXP operator interviews,
showing how essential collaboration with stakeholders is to understanding the causes of performance degradations.
As part of the Internet Society (ISOC) strategy to allow the Internet community to profile
the IXPs of a particular region and monitor their evolution, a route-collector data analyzer was
then developed and afterward, it was deployed and tested in AfriNIC. This open source web
platform titled the “African” Route-collectors Data Analyzer (ARDA) provides metrics, which
picture in real-time the status of interconnection at different levels, using public routing information
available at local route-collectors with a peering viewpoint of the Internet. The results
highlight that a small proportion of Autonomous System Numbers (ASNs) assigned by AfriNIC
(17 %) are peering in the region, a fraction that remained static from April to September 2017
despite the significant growth of IXPs in some countries. They show how ARDA can help detect
the impact of a policy on the IXP substrate and help ISPs worldwide identify new interconnection
opportunities in Africa, the targeted region.
Since broadening the underlying network is not useful without appropriately provisioned services
to exploit it, the thesis then delves into the availability and utilization of the web infrastructure
serving the continent. Towards this end, a comprehensive measurement methodology
is applied to collect data from various sources. A focus on Google reveals that its content infrastructure
in Africa is, indeed, expanding; nevertheless, much of its web content is still served
from the United States (US) and Europe, although being the most popular content source in many
African countries. Further, the same analysis is repeated across top global and regional websites,
showing that even top African websites prefer to host their content abroad. Following that, the
primary bottlenecks faced by Content Providers (CPs) in the region such as the lack of peering
between the networks hosting our probes and poorly configured DNS resolvers are explored to
outline proposals for further ISP and CP deployments.
Considering the above, an option to enrich connectivity and incentivize CPs to establish a
presence in the region is to interconnect ISPs present at isolated IXPs by creating a distributed
IXP layout spanning the continent. In this respect, the thesis finally provides a four-step interconnection
scheme, which parameterizes socio-economic, geographical, and political factors using
public datasets. It demonstrates that this constrained solution doubles the percentage of continental
intra-African paths, reduces their length, and drastically decreases the median of their Round
Trip Times (RTTs) as well as RTTs to ASes hosting the top 10 global and top 10 regional Alexa
websites. We hope that quantitatively demonstrating the benefits of this framework will incentivize
ISPs to intensify peering and CPs to increase their presence, for enabling fast, affordable,
and available access at the Internet frontier.Programa Oficial de Doctorado en Ingeniería TelemáticaPresidente: David Fernández Cambronero.- Secretario: Alberto García Martínez.- Vocal: Cristel Pelsse
Testing the performance of a commercial active network measurement platform
Diplomityössä testataan ja mitataan yhden kaupallisen aktiivimittausalustan suorituskyky ja tarkkuus. Myös alustan kyky havaita tiettyjä tapahtumia tietoverkoissa testataan. Testeissä on mukana kaksi erityyppistä alustaan kuuluvaa mittalaitetta: alhaisen suorituskyvyn Brix 100 Verifier ja tehokkaampi Brix 1000 Verifier. Testauksen tuloksena voidaan sanoa, että molemmat mittalaitetyypit soveltuvat hyvin kiertoaikaviiveen mittaamiseen. Yhdensuuntaisen viiveen mittaukseen Brix 100 ei sovellu etenkään mitattaessa alhaisia viivetasoja (∼1ms). Ulkoista synkronisointilähdettä, kuten GPS-kelloa, käytettäessä Brix 1000 -mittalaitetta voidaan käyttää myös yhdensuuntaisen viiveen mittaamiseen.
Mittausalusta havaitsee verkossa tapahtuvat kuormitustilanteet ja reititinviat, mutta se ei kykene havaitsemaan lyhyitä alle sekunnin mittaisia katkoja.
Työn teoriaosassa esitellään joitain tunnettuja aktiivimittausmekasimeja ja -metodeja sekä pureudutaan aktiivimittauksiin ja niiden ongelmakohtiin yleisellä tasolla. Lisäksi työssä esitellään tunnettuja akateemisia aktiivimittaukseen liittyviä projekteja.In this thesis, a commercial active network measurement platform is tested for performance and accuracy. The platform is also tested for ability to detect certain events in networks. Two types of measurement probes are tested: the low performance Brix 100 Verifier and the high performance Brix 1000 Verifier. It is found that both platform's measurement probe types are accurate when measuring round-trip delay, but do not perform nearly as well when measuring one-way delay. External synchronization, such as GPS, helps the Brix 1000 Verifier to reach sub-millisecond measurement accuracy. As Brix 100 Verifiers do not support external synchronization, their accuracy is suitable only for measuring one-way delays larger than a few milliseconds.
The platform is able to detect sudden high load levels and router failures in a network, but fails to detect short (sub-second) link breaks.
In the theory part of this thesis, some well known active measurement methods and mechanisms are presented. Also, challenges related to active measurement are discussed and some of the recent major academic active measurement projects are introduced
IP Mobility in Wireless Operator Networks
Wireless network access is gaining increased heterogeneity in terms of the types of IP capable access technologies. The access network heterogeneity is an outcome of incremental and evolutionary approach of building new infrastructure. The recent success of multi-radio terminals drives both building a new infrastructure and implicit deployment of heterogeneous access networks. Typically there is no economical reason to replace the existing infrastructure when building a new one. The gradual migration phase usually takes several years.
IP-based mobility across different access networks may involve both horizontal and vertical handovers. Depending on the networking environment, the mobile terminal may be attached to the network through multiple access technologies. Consequently, the terminal may send and receive packets through multiple networks simultaneously. This dissertation addresses the introduction of IP Mobility paradigm into the existing mobile operator network infrastructure that have not originally been designed for multi-access and IP Mobility.
We propose a model for the future wireless networking and roaming architecture that does not require revolutionary technology changes and can be deployed without unnecessary complexity. The model proposes a clear separation of operator roles: (i) access operator, (ii) service operator, and (iii) inter-connection and roaming provider. The separation allows each type of an operator to have their own development path and business models without artificial bindings with each other. We also propose minimum requirements for the new model.
We present the state of the art of IP Mobility. We also present results of standardization efforts in IP-based wireless architectures. Finally, we present experimentation results of IP-level mobility in various wireless operator deployments.Erilaiset langattomat verkkoyhteydet lisääntyvät Internet-kykyisten teknologioiden muodossa. Lukuisten eri teknologioiden päällekkäinen käyttö johtuu vähitellen ja tarpeen mukaan rakennetusta verkkoinfrastruktuurista. Useita radioteknologioita (kuten WLAN, GSM ja UMTS) sisältävien päätelaitteiden (kuten älypuhelimet ja kannettavat tietokoneet) viimeaikainen kaupallinen menestys edesauttaa uuden verkkoinfrastruktuurin rakentamista, sekä mahdollisesti johtaa verkkoteknologioiden kirjon lisääntymiseen. Olemassa olevaa verkkoinfrastruktuuria ei kaupallisista syistä kannata korvata uudella teknologialla yhdellä kertaa, vaan vaiheittainen siirtymävaihe kestää tyypillisesti useita vuosia.
Internet-kykyiset päätelaitteet voivat liikkua joko saman verkkoteknologian sisällä tai eri verkkoteknologioiden välillä. Verkkoympäristöstä riippuen liikkuvat päätelaitteet voivat liittyä verkkoon useiden verkkoyhteyksien kautta. Näin ollen päätelaite voi lähettää ja vastaanottaa tietoliikennepaketteja yhtäaikaisesti lukuisia verkkoja pitkin. Tämä väitöskirja käsittelee Internet-teknologioiden liikkuvuutta ja näiden teknologioiden tuomista olemassa oleviin langattomien verkko-operaattorien verkkoinfrastruktuureihin. Käsiteltäviä verkkoinfrastruktuureita ei alun perin ole suunniteltu Internet-teknologian liikkuvuuden ja monien yhtäaikaisten yhteyksien ehdoilla.
Tässä työssä ehdotetaan tulevaisuuden langattomien verkkojen arkkitehtuurimallia ja ratkaisuja verkkovierailujen toteuttamiseksi. Ehdotettu arkkitehtuuri voidaan toteuttaa ilman mittavia teknologisia mullistuksia. Mallin mukaisessa ehdotuksessa verkko-operaattorin roolit jaetaan selkeästi (i) verkko-operaattoriin, (ii) palveluoperaattoriin ja (iii) yhteys- sekä verkkovierailuoperaattoriin. Roolijako mahdollistaa sen, että kukin operaattorityyppi voi kehittyä itsenäisesti, ja että teennäiset verkkoteknologiasidonnaisuudet poistuvat palveluiden tuottamisessa. Työssä esitetään myös alustava vaatimuslista ehdotetulle mallille, esimerkiksi yhteysoperaattorien laatuvaatimukset.
Väitöskirja esittelee myös liikkuvien Internet-teknologioiden viimeisimmän kehityksen. Työssä näytetään lisäksi standardointituloksia Internet-kykyisissä langattomissa arkkitehtuureissa
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