To support real-time communication, multi-radio multi-channel city-wide WMNs (Wireless Mesh Networks) are studied in this paper. In the studied WMNs, a WMN router is equipped with two communication interfaces/radios, one is working on 2.4GHz for the client accessing, and the other is working on 5GHz for the backhaul communication. First, a greedy static channel assignment algorithm for access i...

Network Calculus is an attractive theory to derive deterministic bounds on end-to-end performance measures. Nevertheless bounding tightly and quickly the worst-case delay or backlog of a flow over a path with cross-traffic remains a challenging problem. This paper carries on with the study of configurations where a main flow encounters some cross-traffic flows which interfere over connected sub...

We describe an eecient fair queuing scheme, Leap Forward Virtual Clock, that provides end-to-end delay bounds almost identical to that of PGPS fair queuing, along with throughput fairness. Our scheme can be implemented with a worst-case time O(log logN) per packet (inclusive of sorting costs), which improves upon all previously known schemes that achieve guaranteed delay and throughput fairness...

We introduce a general methodology for designing integrated shaping and scheduling algorithms for packet networks that provide fairness, low end-to-end delay, and low burstiness. The methodology is based on integrating a shaping mechanism with a scheduler from the class of Rate-Proportional Servers (RPS) deened in 10]. The resulting algorithms provide an end-to-end delay bound identical to that...

A uniform, exible approach is proposed for analysing the feasibility of deadline scheduled real-time systems. In its most general formulation, the analysis assumes sporadically periodic tasks with arbitrary deadlines, release jitter, and shared resources. System overheads of a tick driven scheduler implementation, and scheduling of soft aperiodic tasks are also accounted for. A procedure for th...

We model an ATM network comprising an input queuing cell switching hub. Customer access lines are multiplexed into the relatively faster input links of this hub. Each access multiplexer is fed by on/oo sources. Motivated by the fact that an ATM network should support both bursty as well as smooth traac, we consider the scenario in which some multiplexers are fed by sources with long bursts of c...

Through comprehensive simulation studies, we have evaluated the ATM layer end-to-end performance of a Constant Bit Rate (CBR) MPEG2 connection. For most practical cases that we have considered, a Cell Delay Variation (CDV) value of 160sec is obtained (using 155 Mbps OC-3 rate), well below the 1 msec worst case stated in prior studies 1]]2]. The results also indicate that the Uniform distributio...

Supporting both real-time and fault-tolerance properties in systems is challenging because real-time systems require predictable end-to-end schedules and bounded temporal behavior in order to meet task deadlines. However, system failures, which are typically unanticipated events, can disrupt the predefined real-time schedule and result in missed task deadlines. Such disruptions to the real-time...

In this chapter we show how to derive performance bounds for tandem queueing systems using Network Calculus, a deterministic theory for performance analysis. We introduce the basic concepts of Network Calculus, namely arrival and service curves, and we show how to use them to compute performance bounds in an end-to-end perspective. As an application of the above theory, we evaluate tandems of n...

This paper proposes a switched Ethernet network that supports real-time communication with guaranteed bit rate and end-to-end delay bound. In our proposal, the source nodes use Earliest Deadline First (EDF) scheduling, while the switch uses First Come First Served (FCFS) to control periodic real-time traffic belonging to logical realtime connections. The schedulability condition is drawn and th...