41 research outputs found
A new proposal for assuring services in internet
In this paper we present a new mechanism
to provide an assured service in terms of target rate
and fair excess bandwidth, like the Internet Assured
Service. Research in Internet Assured Service faced
up both questions in separate ways proposing
different traffic conditioners to work with the RIO
buffer management, and proposing different
modifications to this buffer management, among
others. In this work, we suggest using a buffer
management scheme different from RIO that also
treats in-of-profile and out-of-profile packets
differently but avoiding interference between them.
This scheme is used together with the Counters Based
traffic conditioner because of its high accuracy in
guaranteeing target rates. We evaluate and compare
by simulation the performance of our proposal using
TCP RENO sources. One important issue to be
considered is that the proposal is a feasible
alternative to the standard architecture for
Differentiated Services in Internet.This work was supported by the Spanish
Research Council under grant TIC2000-1734-
C03-03
Counters-based modified traffic conditioner
Traffic conditioners play a key role in implementing the Assured Service in the framework
of the DiffServ approach. Many research papers have focused on finding the best traffic conditioner
able to assure contracted target rates and to fairly distribute the excess bandwidth among competing
sources. Nevertheless, none of the proposals presented so far accomplishes simultaneously both
features. We propose a traffic conditioner for the Internet Assured Service called Counters-Based
Modified (CBM) that strictly guarantees target rates and performs a fair share of the excess
bandwidth among TCP Reno sources. The ability of strictly providing the inbound bandwidth is
inherited from its predecessor the Counters-Based algorithm, and the fairness in the outbound
bandwidth distribution is met by probabilistically dropping OUT packets in the traffic conditioner. To
determine the dropping probability of an OUT packet, the amount of excess bandwidth and the
average RTT of all connections in the traffic conditioner have to be known. Although this fact implies
using some sort of signaling, it results more feasible than other proposed intelligent traffic
conditioners. The CBM traffic conditioner is evaluated under different conditions by simulation using
TCP Reno sources. Simulation results presented in this paper lead us to suggest it as a feasible
election for the traffic conditioner device implementation in DiffServ.This work was supported by the Spanish Research Council under grant FAR-IP TIC2000-1734-C03-03
Satellite Networks: Architectures, Applications, and Technologies
Since global satellite networks are moving to the forefront in enhancing the national and global information infrastructures due to communication satellites' unique networking characteristics, a workshop was organized to assess the progress made to date and chart the future. This workshop provided the forum to assess the current state-of-the-art, identify key issues, and highlight the emerging trends in the next-generation architectures, data protocol development, communication interoperability, and applications. Presentations on overview, state-of-the-art in research, development, deployment and applications and future trends on satellite networks are assembled
SZEROKOPASMOWE SATELITARNE SIECI DANYCH W KONTEKŚCIE DOSTĘPNYCH PROTOKOŁÓW I PLATFORM CYFROWYCH
Satellites are the transmission medium for providing connectivity and building global, continental, or regional networks around the world (satellite operators effectively use satellites to support Internet traffic), and point-to-point connections are also possible. In practical use, there are combinations of VSAT networks with terrestrial wireless extensions, allowing end users to increase the capabilities offered via satellite. This paper provides selected information on broadband satellite networks using VSAT technology, including available protocols and transmission platforms. The aim of the article is also to present the chosen technical aspects of satellite networks working with the usage of VSAT technology.Satelity stanowią medium transmisyjne dla zapewnienia łączności i budowy sieci globalnych, kontynentalnych czy regionalnych na całym świecie (operatorzy satelitarni efektywnie wykorzystują satelity do obsługi ruchu internetowego), przy czym możliwe są także połączenia typu punkt-punkt. W praktycznym użyciu są kombinacje sieci VSAT z bezprzewodowymi rozszerzeniami naziemnymi, co pozwala zwiększyć użytkownikom końcowym możliwości oferowane za pośrednictwem satelity. W artykule zamieszczono wybrane informacje na temat szerokopasmowych sieci satelitarnych z wykorzystaniem technologii VSAT, z uwzględnieniem dostępnych protokołów i platform transmisyjnych. Celem artykułu jest także przedstawienie wybranych aspektów technicznych sieci satelitarnych pracujących z wykorzystaniem technologii VSAT
A comparison of ATM and IP QoS network capabilities for handling LAN traffic with QoS differentiation, Journal of Telecommunications and Information Technology, 2003, nr 4
Now, a network operator must choose between two packet switched technologies for providing QoS in WAN networks, which are ATM and IP QoS [3, 4, 9]. As ATM has reached the maturity with capabilities for offering a number of different network services (i.e. CBR, VBR, ABR, UBR, GFR), the IP QoS with network services like expedited forwarding, assured forwarding, etc. is still at developing phase but nevertheless is commonly regarded as capable to guarantee in near future similar QoS level as ATM. This paper tries to compare the efficiency of the mentioned technologies (in case of IP QoS network the AQUILA network concept [1, 2] is investigated) for handling traffic generated by LANs with QoS differentiation. This is extremely required since the applications running in LAN differ in QoS requirements and emitted traffic profiles (streaming, elastic). Therefore, a classification process of outgoing LAN traffic into predefined sub-streams should be performed at the entry point to WAN network (edge ATM switch or IP router). Furthermore, particular sub-streams are submitted to adequate WAN network service, available in ATM or IP QoS. The paper presents the experimental results, measured in the test bed, corresponding to QoS level and QoS differentiation provided by ATM and IP QoS core. For this purpose, a set of representative applications currently available to a LAN user was selected demanding from the core different QoS level. They correspond to streaming applications like VoIP with QoS objectives represented mainly by packet delay characteristics and elastic applications controlled by TCP protocol with minimum guaranteed throughput/ goodput as target
Performance evaluation of profiler mechanisms for the internet assured service
As Internet is rapidly growing and receiving traffic from multimedia applications that are sensitive to available
bandwidth and delay experienced in the network, there is a strong need for quality of service (QoS) support. The
Integrated and Differentiated Service models are two approaches for adding QoS to Internet. The Assured Service is an
end-to-end service based on the Differentiated Service architecture. In this paper, we study and compare the
performance of three profiler mechanisms to provide the guaranties of an Internet Assured Service. Two of them, TSW
and Leaky Bucket are the most commonly used, and the third is a new Counter Based profiler, which is proposed in this
paper. The study is done by simulation employing TCP RENO sources.This work was partly supported by the Spanish Research Council under grant TIC2000-1734-C03-03
End-to-end TCP performance of the couple CBM traffic conditioner and RIO buffer management in a three node topology
Despite the abundant literature written about the AF PHB,
no solution has been found to efficiently face up its two
goals, assuring a minimum rate to the users and offering a
fair distribution of the excess bandwidth if available. The
Counters Based Modified (CBM) traffic conditioner,
presented in a previous work, is able to achieve these
objectives in single-node topologies. This paper raises
issues with providing bandwidth assurance and spare
bandwidth distribution for TCP flows in more complex
topologies than usual. Simulation results explore the
effect of target rates, round trip times, and efficiency of
CBM when up to three network nodes implement service
differentiation, including in some cases the coexistence of
assured service and best-effort traffics.This work was supported by the Spanish Research
Council under projects TEC2004-05622-C04-02/TCM
and TIC2001-3339-C02-02