Real-time Traffic Requirements Research Articles

Adaptive hybrid arbiter design for real-time traffic-aware scheduling

PurposeThis work focused on a basic building block of an allocation unit that carries out the critical job of deciding between the conflicting requests, i.e. an arbiter unit. The purpose of this work is to implement an improved hybrid arbiter while harnessing the basic advantages of a matrix arbiter.Design/methodology/approachThe basic approach of the design methodology involves the extraction of traffic information from buffer signals of each port. As the traffic arrives in the buffer of respective ports, information from these buffers acts as a source of differentiation between the ports receiving low traffic rates and ports receiving high traffic rates. A logic circuit is devised that enables an arbiter to dynamically assign priorities to different ports based on the information from buffers. For implementation and verification of the proposed design, a two-stage approach was used. Stage I comprises comparing the proposed arbiter with other arbiters in the literature using Vivado integrated design environment platform. Stage II demonstrates the implementation of the proposed design in Cadence design environment for application-specific integrated chip level implementation. By using such a strategy, this study aims to have a special focus on the feasibility of the design for very large-scale integration implementation.FindingsAccording to the simulation results, the proposed hybrid arbiter maintains the advantage of a basic matrix arbiter and also possesses the additional feature of fault-tolerant traffic awareness. These features for a hybrid arbiter are achieved with a 19% increase in throughput, a 1.5% decrease in delay and a 19% area increase in comparison to a conventional matrix arbiter.Originality/valueThis paper proposes a traffic-aware mechanism that increases the throughput of an arbiter unit with some area trade-off. The key feature of this hybrid arbiter is that it can assign priorities to the requesting ports based upon the real-time traffic requirements of each port. As a result of this, the arbiter is dynamically able to make arbitration decisions. Now because buffer information is valuable in winning the priority, the presence of a fault-tolerant policy ensures that none of the priority is assigned falsely to a requesting port. By this, wastage of arbitration cycles is avoided and an increase in throughput is also achieved.

Enhancing the Quality of Service for Real Time Traffic over Optical Burst Switching (OBS) Networks with Ensuring the Fairness for Other Traffics.

Optical burst switching (OBS) networks have been attracting much consideration as a promising approach to build the next generation optical Internet. A solution for enhancing the Quality of Service (QoS) for high priority real time traffic over OBS with the fairness among the traffic types is absent in current OBS’ QoS schemes. In this paper we present a novel Real Time Quality of Service with Fairness Ratio (RT-QoSFR) scheme that can adapt the burst assembly parameters according to the traffic QoS needs in order to enhance the real time traffic QoS requirements and to ensure the fairness for other traffic. The results show that RT-QoSFR scheme is able to fulfill the real time traffic requirements (end to end delay, and loss rate) ensuring the fairness for other traffics under various conditions such as the type of real time traffic and traffic load. RT-QoSFR can guarantee that the delay of the real time traffic packets does not exceed the maximum packets transfer delay value. Furthermore, it can reduce the real time traffic packets loss, at the same time guarantee the fairness for non real time traffic packets by determining the ratio of real time traffic inside the burst to be 50–60%, 30–40%, and 10–20% for high, normal, and low traffic loads respectively.

Two Phase Admission Control for QoS Mobile Ad Hoc Networks

In this paper a novel and effective two phase admission control (TPAC) for QoS mobile ad hoc networks is proposed that satisfies the real-time traffic requirements in mobile ad hoc networks. With a limited amount of extra overhead, TPAC can avoid network congestions by a simple and precise admission control which blocks most of the overloading flow-requests in the route discovery process. When compared with previous QoS routing schemes such as QoS-aware routing protocol and CACP protocols, it is shown from system simulations that the proposed scheme can increase the system throughput and reduce both the dropping rate and the end-to-end delay. Therefore, TPAC is surely an effective QoS-guarantee protocol to provide for real-time traffic.

Single phase admission control for QoS-routing protocol in ad hoc networks

In this paper, in order to fulfill real-time traffic requirements in ad hoc networks, a novel and effective single phase admission control (SPAC) scheme for QoS-routing protocols has been proposed. The SPAC scheme is based on the ad hoc on-demand distance vector (AODV) protocol with slight modifications of control packets; network congestions are avoided by a simple and precise admission control that blocks most of the overloading flow requests in the route-discovery process. System simulations show that the SPAC scheme and its performance is comparable to the contention-aware admission control protocol (CACP)-Multihop performance in all respects; the SPAC scheme is also simpler. As compared to a QoS-aware routing protocol employing either “listen” or “hello” scheme, the SPAC protocol offers higher throughput and remarkably less end-to-end delays under heavy loads.

An 802.11e HCCA scheduler with an end-to-end quality aware territory method

In this paper we present a solution for the IEEE 802.11e HCCA ( Hybrid coordination function Controlled Channel Access) mechanism which aims both at supporting strict real-time traffic requirements and, simultaneously, at handling TCP applications efficiently. Our proposal combines a packet scheduler and a dynamic resource allocation algorithm. The scheduling discipline is based on the Monolithic Shaper-Scheduler, which is a modification of a General Processor Sharing (GPS) related scheduler. It supports minimum-bandwidth and delay guarantees and, at the same time, it achieves the optimal latency of all the GPS-related schedulers. In addition, our innovative resource allocation procedure, called the territory method, aims at prioritizing real time services and at improving the performance of TCP applications. For this purpose, it splits the wireless channel capacity (in terms of transmission opportunities) into different territories for the different types of traffic, taking into account the end-to-end network dynamics. In order to give support to the desired applications, we consider the following traffic classes: conversational, streaming, interactive and best-effort. The so called territories shrink or expand depending on the current quality experienced by the corresponding traffic class. We evaluated the performance of our solution through extensive simulations in a heterogeneous wired-cum-wireless scenario under different traffic conditions. Additionally, we compare our proposal to other HCCA scheduling algorithms, the HCCA reference scheduler and Fair Hybrid Coordination Function (FHCF). The results show that the combination of the MSS and the territory method obtains higher system capacity for VoIP traffic (up to 32 users) in the simulated scenario, compared to FHCF and the HCCA reference scheduler (13 users). In addition, the MSS with the territory method also improves the throughput of TCP sources (one FTP application achieves between 6.1 Mbps without VoIP traffic and 2.1 Mbps with 20 VoIP users) compared to the reference scheduler (at most 388 kbps) and FHCF (with a maximum FTP throughput of 4.8 Mbps).