Admission Control Protocol Research Articles

Flow admission control for multi-channel multi-radio wireless networks

Providing Quality of Service (QoS) is a major challenge in wireless networks. In this paper we propose a distributed call admission control protocol (DCAC) to do both bandwidth and delay guaranteed call admission for multihop wireless mesh backbone networks, by exploiting the multi-channel multi-radio (mc-mr) feature. We propose a novel routing metric for route setup, and present an efficient distributed algorithm for link reservation that satisfies the required bandwidth and reduces the delay by a local scheduling that minimizes one hop delay. To the best of our knowledge, this is the first distributed protocol that embeds mc-mr feature in Time Division Medium Access (TDMA) to do QoS call admission in wireless backbone networks. Extensive simulation studies show that our protocol significantly improves network performance on supporting QoS sessions compared with some widely used protocols.

Admission control schemes for 802.11-based multi-hop mobile ad hoc networks: a survey

Mobile ad hoc networks (MANETs) promise unique communication opportunities. The IEEE 802.11 standard has allowed affordable MANETs to be realised. However, providing quality of service (QoS) assurances to MANET applications is difficult due to the unreliable wireless channel, the lack of centralised control, contention for channel access and node mobility. One of the most crucial components of a system for providing QoS assurances is admission control (AC). It is the job of the AC mechanism to estimate the state of the network's resources and thereby to decide which application data sessions can be admitted without promising more resources than are available and thus violating previously made guarantees. Unfortunately, due to the aforementioned difficulties, estimating the network resources and maintaining QoS guarantees are non-trivial tasks. Accordingly, a large body of work has been published on AC protocols for addressing these issues. However, as far as it is possible to tell, no wide-ranging survey of these approaches exists at the time of writing. This paper thus aims to provide a comprehensive survey of the salient unicast AC schemes designed for IEEE 802.11- based multi-hop MANETs, which were published in the peer-reviewed open literature during the period 2000-2007. The relevant considerations for the design of such protocols are discussed and several methods of classifying the schemes found in the literature are proposed. A brief outline of the operation, reaction to route failures, as well as the strengths and weaknesses of each protocol is given. This enables patterns in the design and trends in the development of AC protocols to be identified. Finally, directions for possible future work are provided.

A Call Admission Control Protocol for Multimedia Cellular Networks

The performance of any cellular wireless network, as well as its revenue (number of customers using the network, and their degree of satisfaction) is determined to a great extent by its call admission control (CAC) protocol. As its name implies, the CAC determine if a new call request is granted, or rejected. In this paper, we propose a call admission control protocol for cellular multimedia wireless networks. Multimedia networks are characterized by a wide variety of bandwidth requests, priorities, and drop-off/rejection requirements by different customers. Our protocol depends on degrading the existing calls, according to their degradation priority, by reducing the bandwidth allocated to them in order to admit new calls according to their admission priority. Our protocol is too complicated for an analytical solution. However we present a Markov Model of a simplified version of our protocol for completeness, a Markov representation of the protocol is too complicated to be of any real value. Extensive simulation results show how our proposed protocol can improve the drop-off/rejection ratio for large bandwidth calls and at the same time maintain the quality of service requested by important calls.

Cross-layer cooperation for accurate admission control decisions in mobile ad hoc networks

Mobile ad hoc networks (MANETs) are unpredictable by nature. Providing any kind of reliability for quality of service (QoS) in such networks is challenging. Quantifying available resources accurately, avoiding interference with ongoing QoS traffic and adapting to QoS violations caused by nodes' mobility are the main concerns for the design of an efficient admission control protocol in MANETs. Adaptive admission control (AAC), a novel admission control protocol which uses robust and accurate resource estimation and prediction techniques for relevant admission decisions has been proposed. Furthermore, AAC uses statistical QoS provision to counteract the QoS threatening mobility. Through simulations, we show that our proposed scheme outperforms existing approaches in terms of correctness and overall performance.

Distributed Flow Admission Control for Multimedia Services Over Wireless Ad Hoc Networks

In this paper we propose a novel Priority-based Distributed flow Admission Control (PDAC) protocol to provide Quality of Service (QoS) to multimedia applications over the Dynamic Source Routing (DSR) protocol-based wireless ad hoc networks. In contrast to short-term packet forwarding, medium and long-term multimedia and real-time traffic may benefit from `flow'-based transmission due to the reduction in the packet-level control overhead. In this paper, we introduce a new DSR option called the "Admission Control Option" for flow establishment, and present a new scalable transmission rate reservation protocol to support bandwidth-constrained traffic flows in interference-limited wireless ad hoc networks. It allows a node in the wireless ad hoc network to establish or discard a traffic flow state based on the global knowledge of traffic flow priority, and local knowledge in the form of interference and effective transmission rate. The PDAC scheme can also operate in a `cross-layer' protocol architecture that encompasses the network layer and the MAC layer.

Perceptive admission control for wireless network quality of service

As wireless networks become more widely used, there is a growing need to support advanced services, such as multimedia streaming and voice over IP. Traditional approaches to guarantee quality of service (QoS) work well only with predictable channel and network access. In wireless mobile networks, where conditions dynamically change as nodes move about the network, a stateless, high level approach is required. Since shared wireless resources are easily over-utilized, the load in the network must be controlled so that an acceptable QoS for real-time applications can be maintained. If minimum real-time requirements are not met, these unusable packets waste scarce bandwidth and hinder other traffic, compounding the problem. To enable high QoS for all admitted traffic, we propose the Perceptive Admission Control (PAC) protocol. PAC monitors the wireless channel and dynamically adapts admission control decisions to enable high network utilization while preventing congestion. Through discussion, simulations and testbed experiments, we demonstrate that PAC ensures low packet loss and delay for all admitted flows.

Resource information acquisition for QoS provision in mobile ad hoc networks

Quantifying available resources is the main concern for the design of an efficient admission control protocol in mobile ad hoc networks. Proposed is a novel signalling strategy for efficient acquisition of bandwidth information and this is evaluated through accuracy and overhead analysis.

Throughput guarantees for multi-priority traffic in ad hoc networks

In this paper, we present MPARC (Multi-Priority Admission and Rate Control), a novel joint admission control and rate policing protocol for multi-priority ad hoc networks. MPARC is based on our novel bandwidth allocation model, which captures the bandwidth allocation for saturated, unsaturated and semi-saturated networks. MPARC guarantees that the throughput of admitted realtime flows will not decrease due to later arriving realtime flows with equal or lower priorities or due to best effort flows. MPARC achieves this goal by performing accurate admission control on every newly arriving realtime flow and appropriate rate policing on all best effort traffic. Through simulation, we demonstrate that MPARC has better performance than existing approaches.

Contention-aware admission control for ad hoc networks

An admission control algorithm must coordinate between flows to provide guarantees about how the medium is shared. In wired networks, nodes can monitor the medium to see how much bandwidth is being used. However, in ad hoc networks, communication from one node may consume the bandwidth of neighboring nodes. Therefore, the bandwidth consumption of flows and the available resources to a node are not local concepts, but related to the neighboring nodes in carrier-sensing range. Current solutions do not address how to perform admission control in such an environment so that the admitted flows in the network do not exceed network capacity. In this paper, we present a scalable and efficient admission control framework - contention-aware admission control protocol (CACP) - to support QoS in ad hoc networks. We present several options for the design of CACP and compare the performance of these options using both mathematical analysis and simulation results. We also demonstrate the effectiveness of CACP compared to existing approaches through extensive simulations.

Multi-path admission control for mobile ad hoc networks

To enable the use of applications that require real-time communication in ad hoc networks, an admission control mechanism must be in place to prevent the network from becoming congested, since congestion results in reduced quality of service for applications. Current admission control solutions encounter problems in the face of mobility, resulting in unacceptable disruptions in communication. To solve this problem, we apply multi-path routing mechanisms and propose a new admission control protocol. We show through simulation that our solution is able to prevent communication disruptions and meet the QoS needs of the application.

Parsimonious estimates of bandwidth requirement for quality of service packet networks

In guaranteed Quality of Service (QoS) packet networks like future QoS Internet quantifying resource usage is a key issue for traffic management. Within this the estimated bandwidth requirements of traffic flows are apparently important building blocks of decisions made by connection admission control, QoS routing and resource reservation protocols. This paper focuses on bandwidth requirement estimators under the framework of bufferless fluid flow multiplexing ( bffm) which is a suitable modeling approach for scenarios with high network utilization with large number of traffic flows multiplexed. The bandwidth requirement estimates proposed have acceptable accuracy and are parsimonious, that is they need very few pieces of information on traffic flows which are either measurable in straightforward manner or known a priori and propagated through the nodes of networks. These properties are essential for efficient implementations.

End-to-end adaptive QoS provisioning over GPRS wireless mobile network

The General Packet Radio Service (GPRS) offers performance guaranteed packet data services to mobile users over wireless frequency-division duplex links with time division multiple access, and core packet data networks. This paper presents a dynamic adaptive guaranteed Quality-of-Service (QoS) provisioning scheme over GPRS wireless mobile links by proposing a guaranteed QoS media access control (GQ-MAC) protocol and an accompanying adaptive prioritized-handoff call admission control (AP-CAC) protocol to maintain GPRS QoS guarantees under the effect of mobile handoffs. The GQ-MAC protocol supports bounded channel access delay for delay-sensitive traffic, bounded packet loss probability for loss-sensitive traffic, and dynamic adaptive resource allocation for bursty traffic with peak bandwidth allocation adapted to the current queue length. The AP-CAC protocol provides dynamic adaptive prioritized admission by differentiating handoff requests with higher admission priorities over new calls via a dynamic multiple guard channels scheme, which dynamically adapts the capacity reserved for dealing with handoff requests based on the current traffic conditions in the neighboring radio cells. Integrated services (IntServ) QoS provisioning over the IP/ATM-based GPRS core network is realized over a multi-protocol label switching (MPLS) architecture, and mobility is supported over the core network via a novel mobile label-switching tree (MLST) architecture. End-to-end QoS provisioning over the GPRS wireless mobile network is realized by mapping between the IntServ and GPRS QoS requirements, and by extending the AP-CAC protocol from the wireless medium to the core network to provide a unified end-to-end admission control with dynamic adaptive admission priorities.

High-capacity packet-switched optical ring network

We propose a novel architecture with MAC and admission control protocols for a high-capacity packet-switched optical ring network. In this network the link capacity significantly exceeds the node bit rate. Nodes transmit and receive packets on multiple wavelengths in parallel by using novel optical techniques. Network control is simple since the load is balanced over wavelengths at the physical layer. The MAC protocol is based on credits, and the derived admission control protocol has similar complexity as in a single channel network. Consequently, the network can follow fast traffic changes which are typical in data networks.

Resource allocation rules for providing performance guarantees to traffic aggregates in a DiffServ environment

The background of this paper is the Differentiated Services (DiffServ) approach to introduce quality of service in Internet. We consider connection admission control (CAC) protocols over the DiffServ layer for providing performance guarantees. The challenging aspect is that flows' statistics may change inside networks. Our analysis, based on Network Calculus, shows that if flows are shaped at edge routers only, it is possible to provide performance guarantees to traffic aggregates in terms of delay and losses. We have applied these results to two CAC techniques. The former guarantees hard performance, while the latter can capture the traffic fluctuations and allows overbooking during periods of source inactivity.

An ECN probe-based connection acceptance control

Connection acceptance control is a mechanism which can be used to moderate the load placed on a network by turning away connection requests during times of overload. Traditionally these mechanisms have been implemented by setting up state within a network using signalling protocols, such as the IETF's Resource Reservation Protocol. There have been recent proposals for admission control based on end-systems probing the network to infer network load. These distributed algorithms often have less router state and hence scale more easily. This paper discusses an ECN (Explicit Congestion Notification) probe-based admission control protocol that is fast, scalable and robust. The protocol's performance is then studied through simulation. It is concluded that probe-based admission control is viable in both partitioned and integrated networks, but more research is needed to understand the implications for network policy control.

Admission control algorithms for multicast sessions with multiple streams

Real-time multicast communication is considered, in which each destination makes an individual bid for delivery of a subset of real-time hierarchically encoded streams that are offered to the session by the source. The objective is to customize stream delivery to destinations, based on their requests and network constraints. Admission control procedures, which consider requests for multiple streams from multiple destinations and resolve contention when users' requests exceed available network resources, are presented. Specifications for four admission control procedures are presented and their properties analyzed. A performance measure for admission control is defined to be the total gain for the source that equals the sum of bids by the users taking delivery of the streams they ordered. Simulation results of the performance of the procedures are presented and compared to the performance of an optimal, but highly complex, admission control algorithm. In this paper the assumption is that the routing tree is already in place and the focus is on managing users' requests and deciding on which stream to deliver to each destination. This is done by signaling protocols that transfer messages containing users' requests and resource allocation commands between a source and the destinations. In addition, admission control protocols take users' requests and network resources as their input and issue as outputs the decisions on which request to admit (and allocate resources for) and which to reject.

A reservation-based multicast (RBM) routing protocol for mobile networks: initial route construction phase

We propose a combined multicast routing, resource reservation and admission control protocol, termed Reservation-Based Multicast (RBM), that borrows the “Rendez-vous Point” or “Core” concept from multicast routing algorithms proposed for the Internet, but which is intended for operation in mobile networks and routes hierarchically-encoded data streams based on user-specified fidelity requirements, real-time delivery thresholds and prevailing network bandwidth constraints. The protocol exhibits the fully distributed operation and receiver-initiated orientation of these proposed algorithms; but, unlike them, the protocol is tightly coupled to a class of underlying, distributed, unicast routing protocols thereby facilitating operation in a dynamic topology. This paper focuses on the initial route construction phase, assumed to occur during a static “snapshot” of the dynamic topology, and is therefore applicable to fixed networks as well, e.g. the Internet.