Design of a crossbar VOQ real-time switch with clock-driven scheduling for a guaranteed delay bound

Determination of Delay Bound over Multi-hop Real-Time Switches with Virtual Output Queuing

“…According to the crossbar rule [14], each input port can be connected to only one output port at a time, and vice versa. Consequently, the clearance time T clear has a lower bound that is the maximum number of packets at any port:…”

“…By minimally modifying iSLIP [11], [12], which is already widely implemented in commercial products, Qixin et al [13] designed an efſcient crossbar switch for real-time applications based on virtual-output-queuing. That design provided a mechanism for guaranteeing that a certain number of communication slots are allocated to a task over a ſxed time interval, under the assumption of deterministic and periodic real-time trafſc; a real-time crossbar switching algorithm we have proposed [14] differs from the work of Qixin et al in that it requires no assumption about trafſc periodicity. Their optimal clearance-time switching policy, together with virtual-output-queuing and clock-driven scheduling, guarantees that any feasible 1 trafſc can be switched in two clock periods.…”

Delay-Constrained Input-Queued Switch

“…However, with the proliferation of real-time applications, the communication networks nowadays need to support more and more delay-constrained traffic. Typical examples include multimedia communication systems such as real-time streaming and video conferencing [8], tactile Internet [9], [10], networked controlled systems (NCSs) such as remote control of unmanned aerial vehicles (UAVs) [11], [12], and cyberphysical systems (CPSs) such as medical tele-operations, Xby-wire vehilces/avionics, factory automation, and robotic collaboration [3]. In such applications, each packet has a hard deadline: if it is not delivered before its deadline, its validity will expire and it will be removed from the system.…”

“…Note that switches can serve delay-constrained traffi c such as tactile applications from both wireless ends and wireline ends. There are some existing works that investigate how to design real-time input-queued switch, e.g., [18], [19], [3]. In [18], the authors proposed two scheduling policies under which the delivery delay of packets is upper bounded by a finite value.…”

“…In [18], the authors proposed two scheduling policies under which the delivery delay of packets is upper bounded by a finite value. In [19], [3], the design goal is to deliver all packets and minimize the maximum delivery delay among all packets. Thus, existing works do not directly guarantee the delivery of delay-constrained traffics where hard deadlines are predetermined by the applications; and they do not allow any packet loss.…”