The issue of QoS management in the radio interface has not been widely studied and the effects of parameters and algorithms in the user and control plane on different bearer services in high traffic situation have bee...
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ISBN:
(纸本)0780379543
The issue of QoS management in the radio interface has not been widely studied and the effects of parameters and algorithms in the user and control plane on different bearer services in high traffic situation have been rarely addressed. This paper describes a virtual time simulator for studying and validating enhanced QoS management functions before their deployment throughout the UNITS Radio Access Network (UTRAN). Several simulations have been run to look into the feasibility of such a tool, and one relevant case is discussed in this paper, where the effectiveness of radio resources utilisation and differentiation among bearer services in terms of call block ratio, throughput, queuing time, object transfer delay and served guaranteed bit rate (GB) traffic load is investigated. The simulation results show the proposed simulator to be an appropriate tool for analysing QoS management functions.
The growth of Internet traffic and the growing variety of Internet applications requires Internet backbone networks to be scalable and have sophisticated quality of service capabilities. Internet backbone routers have...
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ISBN:
(纸本)0780376617
The growth of Internet traffic and the growing variety of Internet applications requires Internet backbone networks to be scalable and have sophisticated quality of service capabilities. Internet backbone routers have evolved to have sub-Tbps switching capacity in a single unit but their switch architectures have limited scalability and that makes their quality of service degrade, as the switches get bigger. This paper proposes a scalable switch architecture for ultra-large-scale switch routers. We first describe the system structure of our proposed backbone switch router and clarify the requirements for the switching capabilities for near future demands. The new switch architecture using crossbar-based switching fabrics and optical interconnection devices follows the requirements to allow a backbone switch router scale up to 82 Tbps and to enable light path switching as well as packet switching. The routing tag and its usage algorithm in the switch and the packaging issues, including the hardware quantities, are also discussed.
Multi-protocol label switching extends the ip destination-based routing protocols to provide new and scalable routing capabilities in connectionless networks using relatively simple packet forwarding mechanisms. MPLS ...
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Multi-protocol label switching extends the ip destination-based routing protocols to provide new and scalable routing capabilities in connectionless networks using relatively simple packet forwarding mechanisms. MPLS networks carry traffic on virtual connections called label switched paths. This paper considers path selection and bandwidth allocation in MPLS networks in order to optimize the network quality of service. The optimization is based upon the minimization of a non-linear objective function which under light load simplifies to OSPF routing with link metrics equal to the link propagation delays. The behavior under heavy load depends on the choice of certain parameters. It can essentially be made to minimize maximal expected utilization, or to maximize minimal expected weighted slacks (both over all links). Under certain circumstances it can be made to minimize the probability that a link has an instantaneous offered load larger than its transmission capacity. We present a model of an MPLS network and an algorithm which optimally distributes the traffic among a set of active paths and reserves a set of back-up paths for carrying the traffic of failed or congested paths. The algorithm is an improvement of the well-known flow deviation non-linear programming method. The algorithm is applied to compute optimal LSPs for a 100-node network carrying a single traffic class. A link carrying some 1400 routes fails. The back-up paths are activated and we compare the performance of the path sets before and after the back-up paths are deployed. (C) 2002 Elsevier Science B.V. All rights reserved.
The adoption of Internet Protocol (ip) in 3G mobile networks has necessitated the need to secure network resources, to protect control plane and user plane traffic and to provide controlled access to network resources...
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ISBN:
(纸本)1932415041
The adoption of Internet Protocol (ip) in 3G mobile networks has necessitated the need to secure network resources, to protect control plane and user plane traffic and to provide controlled access to network resources. 3G networks are complicated networks with many different types of network elements that carry different types of traffic. As a result, multiple security mechanisms are required to satisfy the diverse security needs. In addition, the complexity of 3G networks and their security schemes should not become an obstacle for operators to secure their networks. The deployment and management of the network security should be relatively simple. Policy based security management aims at achieving this goal. Policy based security management allows security rules to be defined and managed in a centralized way and be enforced in a distributed way by individual network element. This paper introduces the concept of policy based security management, examines the security mechanisms in 3G networks and proposes the application of policy based security management to the management of 3G network security.
The proceedings contain 93 papers. The topics discussed include: routing anomaly detection in mobile ad hoc networks;a novel caching scheme for internet based mobile ad hoc networks;a hybrid optical network architectu...
ISBN:
(纸本)0780379454
The proceedings contain 93 papers. The topics discussed include: routing anomaly detection in mobile ad hoc networks;a novel caching scheme for internet based mobile ad hoc networks;a hybrid optical network architecture consisting of optical cross connects and optical burst switches;single- and multi-path logical topology design and traffic grooming algorithm in ip over WDM networks;multicast loss recovery with active injection;scheduling in wireless cellular networks under probabilistic channel information;call admission control in mobile cellular systems using fuzzy associative memory;peer-to-peer approach for global deployment of voice over ip service;protocol for peer-to-peer networking in mobile environments;an approach of integrating Sip in converged multimodal/multimedia communication services;adaptive AIMD rate control for smooth multimedia streaming;dial-controlled hash: reducing path oscillation in multipath networks;and achieving delay and throughput decoupling in distributed fair queueing over ad hoc networks.
This paper provides a reference way to realize bandwidth control, a basic and important part of QoS, in WLAN. Using iptables and TC (trafficcontrol) of Linux, AC (Access control, the boundary node of a mini WLAN) con...
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Constraint-based routing (CR-LDP) extends the features of MPLS Label Distribution Protocol (LDP) working in conjunction with a wide variety of QoS scenarios and services including ip differentiated services, integrate...
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ISBN:
(纸本)1402072686
Constraint-based routing (CR-LDP) extends the features of MPLS Label Distribution Protocol (LDP) working in conjunction with a wide variety of QoS scenarios and services including ip differentiated services, integrated services, traffic engineering, Asynchronous Transfer Mode (ATM) service classes and frame relay. When a large number of CR-LSPs are required a lot of CR-LDP signalling is needed: this paper proposes two techniques - caching and aggregation - to reduce the number of CR-LDP messages by dynamically increasing the number of flows served by each single CR-LSP. The results of a simulation are also used to discuss the performance of such mechanisms.
Video streaming over the Internet is a challenging task since the Internet is a shared environment offering only best effort service. That is, it offers no quality of service and no guarantee of resources in term of (...
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ISBN:
(纸本)3540200509
Video streaming over the Internet is a challenging task since the Internet is a shared environment offering only best effort service. That is, it offers no quality of service and no guarantee of resources in term of (1) bandwidth, (2) transfer delay, (3) delay variation (jitter), and (4) packet losses. Then, network stability and traffic fairness become critical issues. To solve these problems some source rate control and adaptation should be introduced for UDP traffic as well, in such a way that this traffic becomes TCP-compatible "TCP-friendly". In this article we propose an adaptive streaming framework for unicast MPEG-4 streams over TCP/ipnetworks. Based on Audio-Visual Content (AVOs) classification and network congestion feedback, video sources dynamically adds and drops MPEG-4 AVO to the streamed multiplex to conform to the TCP-Friendly Rate control (TFRC) mechanism. Using a content classification model, TFRC automatically adjusts the number of AVOs to be streamed to adapt to network congestion while given much attention to the quality of the service perceived by the end-user. To achieve such a dynamic output rate and video quality adjustment, MPEG-4 AVOs are classified and multiplexed according to both application-level QoS parameters and AVOs semantic descriptors. AVOs requiring same QoS from the network are automatically classified and mapped to one of the available ip DiffServ PHB (Per Hop Behaviors). Performance evaluation shows that transmitted video gracefully adapts to network bandwidth variations while optimizing user perceived quality.
This short paper presents the results of a research on the design, implementation and analysis of a packet scheduling mechanism for multi-traffic classes in the context of DiffServ networks. Our studies aimed at provi...
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This short paper presents the results of a research on the design, implementation and analysis of a packet scheduling mechanism for multi-traffic classes in the context of DiffServ networks. Our studies aimed at providing QoS assurances to real-time applications over ipnetworks. We began by identifying that QoS performance guarantees per-class of traffic aggregate are inherently required in the core of the Internet. We assume that traffic classification based on the application QoS requirements is an indispensable feature for providing QoS guarantees to a wide variety of real-time applications like voice over ip (Voip) and video conferencing due to the scalability issues.
In this paper we compare two traffic models based on Markov modulated Poisson processes (MMPPs), that were designed to capture self-similar behavior over multiple time scales. These models are both constructed by fitt...
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ISBN:
(纸本)0819451274
In this paper we compare two traffic models based on Markov modulated Poisson processes (MMPPs), that were designed to capture self-similar behavior over multiple time scales. These models are both constructed by fitting the distribution of packet counts in a number of time scales. The first model is a superposition of MMPPs where each MMPP describes a different time scale. The second one is obtained as the equivalent to an hierarchical construction process that, starting at the coarsest time scale. successively decomposes MMPP states into new MMPPs to incorporate the characteristics offered by firmer time scales. We evaluate the accuracy of the models by comparing the probability mass function at each time scale, as well as the loss probability and average waiting time in queue, corresponding to measured traces and to traces synthesized according to the proposed models. The analysis is based on three measured traffic traces exhibiting self-similar behavior: the well-known pOct Bellcore trace and two traces measured in a Portuguese ISP. Based on the obtained results, we conclude that both Markovian models have good and very similar performances in matching the characteristics of the data traces over the relevant time scales. However, one advantage of the hierarchical approach is that the number of states of the corresponding MMPP can be much smaller.
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