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

Distributed admission control for QoS and SLS management

This article proposes a distributed admission control (AC) model based on on-line monitoring to manage the quality of Internet services and Service Level Specifications (SLSs) in class-based networks. The AC strategy covers intra- and interdomain operation, without adding significant complexity to the network control plane and involving only edge nodes. While ingress nodes perform implicit or explicit AC resorting to service-oriented rules for SLS and QoS parameters control, egress nodes collect service metrics providing them as inputs for AC. The end-to-end operation is viewed as a cumulative and repetitive process of AC and available service computation.We discuss crucial key points of the model implementation and evaluate its two main components: themonitoring process and the AC criteria. The results show that, using proper AC rules and safety margins, service commitments can be efficiently satisfied, and the simplicity and flexibility of the model can be explored to manage successfully QoS requirements of multiple Internet services.(undefined

TCP throughput guarantee in the DiffServ Assured Forwarding service: what about the results?

Since the proposition of Quality of Service architectures by the IETF, the interaction between TCP and the QoS services has been intensively studied. This paper proposes to look forward to the results obtained in terms of TCP throughput guarantee in the DiffServ Assured Forwarding (DiffServ/AF) service and to present an overview of the different proposals to solve the problem. It has been demonstrated that the standardized IETF DiffServ conditioners such as the token bucket color marker and the time sliding window color maker were not good TCP traffic descriptors. Starting with this point, several propositions have been made and most of them presents new marking schemes in order to replace or improve the traditional token bucket color marker. The main problem is that TCP congestion control is not designed to work with the AF service. Indeed, both mechanisms are antagonists. TCP has the property to share in a fair manner the bottleneck bandwidth between flows while DiffServ network provides a level of service controllable and predictable. In this paper, we build a classification of all the propositions made during these last years and compare them. As a result, we will see that these conditioning schemes can be separated in three sets of action level and that the conditioning at the network edge level is the most accepted one. We conclude that the problem is still unsolved and that TCP, conditioned or not conditioned, remains inappropriate to the DiffServ/AF service

AQUILA network architecture: first trial experiments, Journal of Telecommunications and Information Technology, 2002, nr 2

The paper presents trial experiments with IP QoS network services (NS) defined and implemented in the AQUILA pilot installation. The AQUILA NSs (premium CBR, premium VBR, premium multimedia and premium mission critical) provide a framework for supporting a variety of applications generating both streaming and elastic traffic. The measurement experiments confirm that AQUILA architecture differentiates the QoS offered to these NSs. The presented numerical results were obtained in the test network installed in the Polish Telecom (Warsaw) consisting of 8 CISCO routers

Self-adaptive distributed management of QoS and SLSs in multiservice networks

Apresentação efectuada na International Conference on Integrated Management (IM 2005), Nice, France, May 2005.Distributed service-oriented traffic control mechanisms, operating with minimum impact on network performance, assume a crucial role as regards controlling services quality and network resources transparent and efficiently. In this way, we describe and specify a lightweight distributed admission control (AC) model which provides an uniform solution for managing QoS and SLSs in multiclass and multidomain environments. Taking advantage of the consensual need of on-line service monitoring and traffic control at the network edges, AC decisions are driven by feedback from systematic edge-to-edge measurements of relevant QoS parameters for each service type and SLS utilization. This allows self-adaptive service and resource management, while abstracting from network core complexity and heterogeneity. In this paper, introducing an expressive notation, we specify the high-level entities for multiservice provisioning in a domain and formalize service-dependent AC equations to assure both intra and interdomain model operation. A proof-of-concept of the AC criteria effectiveness in satisfying each service class commitments while achieving high network utilization is provided through simulation

Journal of Telecommunications and Information Technology, 2002, nr 2

kwartalni

Distributed admission control in multiservice IP networks : concurrency issues

In distributed admission control (AC) schemes, handling concurrent AC decisions assumes a relevant role in avoiding over or false acceptance and, consequently, service quality degradation. This problematic is even more intricate in multiservice network environments where distinct service levels need to be fulfilled. This paper debates and points out solutions to mitigate the negative impact that distributed admission of flows might have on the service level guarantees provided to network customers. Keeping in mind that simplicity is a key factor for deployable AC solutions, we suggest and discuss the use of (i) a service-dependent concurrency index; (ii) a token-based system and (iii) a rate-based credit system, as alternative or complementary proposals to minimize or solve QoS degradation resulting from AC false acceptance.(undefined

Handling concurrent admission control in multiservice IP networks

Comunicação apresentada na "Consumer Communications & Networkin Conference 2006", Las Vegas, Nevada, USA, 8-10 Janeiro 2006.This paper debates the problem of handling concurrent admission control decisions in multiservice networks, putting forward solutions to mitigate the negative impact that distributed admission of flows might have on the service level guarantees provided to network customers. Keeping in mind that simplicity is a key factor for deployable solutions, we suggest and discuss the use of (i) a service-dependent concurrency index; (ii) a token-based system and (iii) a rate-based credit system, as alternative or complementary proposals to minimize or solve QoS degradation resulting from AC false acceptance