La norma IEEE 802.6 (DQDB) operando en tiempo real duro

En trabajos previo se ha demostrado que la norma IEEE 802.6 (DQDB) no puede, implementar las disciplinas de Rueda Cíclica Justa o de Periodos Monotónicos Crecientes, salvo que se introduzcan modificaciones tan sustanciales que resulten no implementables con los mecanismos normalizados. El objeto del presente trabajo es analizar las condiciones de diagramabilidad de la red sin alterar sus protocolos de acceso al medio. Se encuentra una expresión para el periodo mínimo de los mensajes de cada nodo en función de la longitus del mensaje, de su distancia al extremo generador de ranuras, del número de nodos aguas arriba y de la función trabajo de los no'dos aguas abajo.Eje: Redes de computadorasRed de Universidades con Carreras en Informática (RedUNCI

La norma IEEE 802.6 (DQDB) operando en tiempo real duro

En trabajos previo se ha demostrado que la norma IEEE 802.6 (DQDB) no puede, implementar las disciplinas de Rueda Cíclica Justa o de Periodos Monotónicos Crecientes, salvo que se introduzcan modificaciones tan sustanciales que resulten no implementables con los mecanismos normalizados. El objeto del presente trabajo es analizar las condiciones de diagramabilidad de la red sin alterar sus protocolos de acceso al medio. Se encuentra una expresión para el periodo mínimo de los mensajes de cada nodo en función de la longitus del mensaje, de su distancia al extremo generador de ranuras, del número de nodos aguas arriba y de la función trabajo de los no'dos aguas abajo.Eje: Redes de computadorasRed de Universidades con Carreras en Informática (RedUNCI

High speed protocols for dual bus and dual ring network architectures

In this dissertation, two channel access mechanisms providing fair and bandwidth efficient transmission on dual bus and dual ring networks with high bandwidth-latency product are proposed. In addition, two effective priority mechanisms are introduced to meet the throughput and delay requirements of the diverse arrays of applications that future high speed networks must support. For dual bus architectures, the Buffer Insertion Bandwidth Balancing (BI_BWB) mechanism and the Preemptive priority Bandwidth Balancing (P_BI_BWB) mechanism are proposed. BI_BWB can significantly improve the delay performance of remote stations. It achieves that by providing each station with a shift register into which the station can temporarily store the upstream stations\u27 transmitted packets and replace these packets with its own transmissions. P_BI_BWB, an enhancement of BI_BWB, is designed to introduce effective preemptive priorities. This mechanism eliminates the effect of low priority on high priority by buffering the low priority traffic into a shift register until the transmission of the high priority traffic is complete. For dual ring architectures, the Fair Bandwidth Allocation Mechanism (FBAM) and the Effective Priority Bandwidth Balancing (EP_BWB) mechanism are introduced. FBAM allows stations to reserve channel bandwidth on a continuous basis rather than wait until bandwidth starvation is observed. Consequently, FBAM does not have to deal with the difficult issue of identifying starvation, a serious drawback of other access mechanisms such as the Local and Global Fairness Algorithms (LFA and GFA, respectively). In addition, its operation requires a significantly smaller number of control bits in the access control field of the slot and its performance is less sensitive to system parameters. Moreover, FBAM demonstrates Max-Min flow control properties with respect to the allocation of bandwidth among competing traffic streams, which is a significant advantage of FBAM over all the previously proposed channel access mechanisms. EP_BWB, an enhancement of FBAM to support preemptive priorities, minimizes the effect of low priority on high priority and supports delay-sensitive traffic by enabling higher priority classes to preempt the transmissions of lower priority classes. Finally, the great potential of EP_BWB to support the interconnection of base stations on a distributed control wireless PCN carrying voice and data traffic is demonstrated