1,721,054 research outputs found
Per-flow QoS support over a stateless Differentiated Services IP domain
No full textThis paper consists of two parts. In the first part, we propose an admission control paradigm, called Gauge & Gate Reservation with Independent Probing (GRIP), devised to operate over a stateless Differentiated Services IP domain. GRIP admits a new flow upon the successful and timely delivery, through the domain, of probing packets independently generated by the end-points. Failed reception of probing packets is interpreted as congestion in the network. Our solution is fully distributed and scalable, as admission control decisions are taken at the edge nodes, and requires no coordination between routers, which are stateless and remain oblivious to individual flows. An interesting feature of the GRIP operation is its backward compatibility (at the expense of experienced performance) with existing routers. The performance of GRIP is related to the capability of routers to locally take decisions about the degree of congestion, and suitably block probing packets when congestion conditions are detected. In the second part of the paper we describe a specific GRIP implementation, characterized by the capability of providing strict Quality of Service guarantees, thanks to suitable assumptions made on the supported traffic and on the traffic control mechanisms, in a specific domain
End-to-end delay and jitter calculus applied to the dimensioning of play-out buffers in ATM networks
No full textA Migration Path to provide End-to-End QoS over Stateless Networks by Means of a Probing-driven Admission Control
No full textThis document proposes a new admission control paradigm, called GRIP
(Gauge&Gate Reservation with Independent Probing), devised to
transparently operate over DiffServ domains. GRIP relies the
decision to admit a new flow upon the successful and timely
delivery, through the Internet, of probe packets independently
generated by the end points.
The key idea is to use failed receptions of probes to discover, at
the end points, that a congestion condition occurs in the network,
and to reject the new admission request. This idea is extremely
close to what TCP congestion control technique does, but it is used
in the novel context of admission control. Similarly to TCP, GRIP is
a pure end-to-end distributed protocol operation, whose intelligence
is kept at the edge of the network and whose operation (i) does not
require any specific protocol implementation in the core routers,
which are stateless and remain oblivious to individual flows, and
(ii) does not require any specific peer and router agreement on the
probes payload information. GRIP is coherent with the architectural
assumptions of RFCs [1,2] and attempts answering to a number of
issues raised in these documents.
While GRIP can be seamlessly applied to DiffServ (and even legacy)
Internet, a marginal increase in QoS is envisioned in these existing
scenarios. The performance of GRIP are in fact related to the
capability of routers to locally take decisions about the degree of
congestion in the network, and suitably drop probe packets when
congestion conditions are detected. However, such decisions are
localized and do not involve any coordination among routers and
between routers and end points. Thus, GRIP opens up a future smooth
migration path toward gradually improved QoS, as routers in
different domain will be enhanced (e.g., with measurement-based
admission decision criteria) without losing inter-operability with
installed devices. Strict end-to-end QoS guarantees are eventually
provided when all the crossed routers are equipped with GRIP
capabilities
Providing UMTS services in a wireless ATM LAN
No full textIn this paper, we will be concerned with a Wireless Wideband ATM LAN (WWLAN) interconnected via a broadband link to an ATM/B-ISDN fixed network. The aim of this work is twofold: i) the definition of the WWLAN protocol architecture and of the interworking functions with the fixed ATM/B-ISDN; ii) the mapping of the UMTS paradigm into the WWLAN scenario. The work is mainly focused on the control plane and on the interactions between WWLAN and B-ISDN for the provision of UMTS services
IN call modelling for the support of multimedia and multipoint services in a B-ISDN
No full textThis paper deals with the integration between the Intelligent Network and the B-ISDN for the support of advanced multimedia and multipoint services. The focus of the paper is the proposal of an enhanced Basic Call State Model (Enhanced-BCSM, E-BCSM) and the description of the internal structure of a Service Switching Function (SSF) that exploits the innovations introduced at the BCSM level. We investigate some different options for an IN/B-ISDN interaction; we adopt a solution that distributes the IN control logic between the Service Control Function (SCF) and the Service Switching Function, describing in details the relevant architectural aspects
Definition and analysis of a reactive congestion control scheme for application to satellite switched networks
No full textA system architecture for satellite communications is outlined. The proposed architecture includes an On-board Switch performing circuit and packet switching and implements the adaptation of real time and non real time services to the satellite communication link, while achieving statistical advantage. The switching scheme is based upon the separation of the incoming traffic in two components: isochronous (V, e.g. voice and video) and non-isochronous (D, e.g. data). These two components are simultaneously supported by TDMAlTDM. The V traffic is known to be bursty and such burstiness can be used to increase significantly the overall system throughput; also, a potential statistical gain can be reaped by packet switching the D traffic. This work focuses on the definition and analysis of a reactive congestion control scheme for D traffic
ACHIEVING STATISTICAL GAIN IN ATM NETWORKS WITH THE SAME COMPLEXITY AS PEAK ALLOCATION STRATEGY
No full textThis paper deals with a novel strategy for Connection Admission Control in ATM networks. This strategy, called Worst Deterministic Pattern Allocation (WDPA), aims at repairing statistical gain of ATM, through a simple and controllable bandwidth allocation. WDPA is based on the concept of preventively constraining information sources to emit their cells according to a superimposed deterministic mask. Resource allocation is performed taking into account only the parameters of the declared deterministic mask. The same allocation rule is utilized in every network section. Application of WDPA to input and output queueing switches is also discussed and its compatibility with both these architectures is demonstrated. A performance study is presented. A comparison of the efficiency resulting from WDPA application with that relevant to peak allocation and pure statistical allocation is presented. Results show that, by fixing a maximum transit delay, WDPA outperforms statistical allocation if path length exceed few hops
Worst Deterministic Pattern Allocation: a viable approach to attain statistical gain in ATM
No full textThis paper deals with a novel strategy for Connection Admission Control in ATM networks. This strategy, called Worst Deterministic Pattern Allocation (WDPA), aims at reaping statistical gain of ATM, through a simple and controllable bandwidth allocation. WDPA is based on the concept of constraining information sources to emit their cells according to a superimposed deterministic pattern. This forced regularity is exploited in order to easily control the cell transfer within the network. Practically, WDPA establishes the worst emission pattern of the source. Resource allocation is performed taking into account only the parameters of the declared deterministic pattern. The same allocation rule is utilized in every network section. Application of WDPA to a large class of switching structures with output buffer is also discussed and its compatibility with this architecture is demonstrated. The presented performance study aims at evaluating the impact of the shaping on the original source cell stream and at determining general criteria for the choice of the deterministic pattern parameters. Finally, we compare the efficiency resulting from application of WDPA with that relevant to peak rate, mean rate and an ideal statistical allocation strategies
Efficient Provision of Performance Guarantees in ATM Networks by means of Deterministic Traffic Handling
No full textIntensive research efforts have by now shown that guaranteeing performance targets, such as no cell loss, bounded cell delay variation and maximum delay, requires quite strict constraints on the traffic source emission characteristics.
We consider a resource allocation strategy based on the shaping of the user offered ATM traffic into a deterministic pattern. The focus of this work is the proposal of a strategy to control the cell transfer through the network, by exploiting the enforced regularity, to optimize the use of network buffering resources, thus enhancing the overall network efficiency. This is realized by a so called Cell Shuffler, located at the switch input ports.
The proposed strategy aims at the following goals: i) to define an easily implementable cell transfer control mechanism, that is independent of the switching node architecture; ii) to allow a dimensioning of the node output port buffers independently of the switch load; iii) to minimize the buffer consumption due to each Virtual Circuit and eventually reap some of the potential multiplexing statistical gain, while still being able to maintain performance guarantees and fairness among different users.
A preliminary performance evaluation focused on the assessment of buffer space requirements in a network node is carried out, to highlight the benefits deriving from the proposed cell transfer control strategy
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