This paper presents an efficient hardware architecture for scheduling connections on a fat-treeinterconnectionnetwork for parallel computing systems. Our technique utilizes global routing information to select upward routing paths so that most conflicts can be resolved. Thus, more connections can be successfully scheduled compared with a local sched- uler. As a result of applying our technique to two-level, three-level and four-level fat-treeinterconnection networks of various sizes in the range of 64 to 4096 nodes, we observe that the improvement of schedulability ratio averages 30% compared with greedy or random local scheduling. Our technique is also scalable and shows increased benefits for large system sizes.
It has been shown that a fat-tree can efficiently (i.e. in no more than poly- logarithmic slowdown) simulate any network of comparable volume or area under the unit wire delay assumption [1–3, 6, 7], and that the fat-pyramid can achieve a logarithmic efficiency under a nonunit (linear) wire delay model . There has been some variation in the exact number of links and the overall connectivity implemented in the models of the fat-tree since its universality was first proved by Leiserson . We refer mainly to the results proved by Greenberg along with those for the fat-pyramid . The fat-pyramid is based on superimposing hierarchical mesh connections on a butterfly fat-tree. We first establish the similarity between a typical butterfly fat-tree and an AFS and prove the universality of the AFS under unit wire delay assumption. We then prove that the AFS is universal under nonunit wire delay condition due to its added ring connectivity. To facilitate our discussion, we illustrate the fat-tree, the fat-pyramid, and the AFS together in Figure 4, which is adapted from Figure 1 of .
We tested the main features of the QsNET on a 64-node cluster of Compaq AlphaServer ES40s, running Tru64 Unix. Each AlphaServer node is equipped with 4 Alpha 667MHz 21264 processors, 8 GB of SDRAM and two 64-bit, 33MHz PCI I/O buses. The Elan3 QM-400 card is attached to one of these buses and links the SMP to a quaternary fattree of dimension three, as the one shown in Figure 2 c). Unless otherwise stated, the communication buffers are allocated in Elan memory in order to isolate I/O bus-related performance
ON a chip with billion transistors, sending a global signal across the chip maintaining a real – time bound may not be possible. To mitigate this problem, one can think of designing an asynchronous system. However, designing an asynchronous system is way more complex than designing a synchronous system . Thus, a viable solution that researchers have taken up is to combine synchronous and asynchronous designs. One such technique at hand is GALS (Globally synchronous and locally asynchronous). GALS solution divides a system into locally decoupled synchronous systems and bring together few of them to form a localized subsystem. These subsystems can then be easily integrated together to form a global solution. The synchronous sub – systems shall be communicating asynchronously at the system level. Thus, decomposing the overall problem of system synchronization to just synchronizing the local subsystems. One of these GALS solutions is Network – On – Chip (NoC). NoC can greatly improve design time by supporting modularity and reuse of complex cores, which enables to attain higher level abstraction in architectural modelling . On – Chip network or Network – On – Chip (NoC) is a communication subsystem embedded on an IC (integrated Circuits) commonly known as ―Chip‖. The micro network embedded on the chip enables communication flow between IPs (Intellectual properties: - So called because of their development by third party companies) cores. A NoC can span synchronous and asynchronous clock domains and can also use unclocked asynchronous logic. Incorporation of a network on the chip brings notable advantages, such as, improved communication between IPs as compared to conventional bus and crossbar interconnection, scalability, and power efficiency of complex SoCs as compared to other design paradigms . Factors that governing NoC includes topology, routing algorithm, flow control etc. Topology which is defined as the placement or arrangement of the above mentioned components to make a structure of the network. A topology can be loosely referred to as the road map, where channels carry messages (data
This section describes the simulation results obtained during the investigation phases. We used OMNeT++, an object-oriented modular discrete event network simulator. A MANET with 100 nodes (identified as comp1, comp2, comp3 …comp100 in simulation) interconnected randomly and spread in some distant geographical location as shown in Fig.5 is used to validate our proposed techniques. It is assumed that the medium have propagation delay of 100 ms.
low network latency. Our design is suitable for a preva- lent 3D CMP architecture where all cores are placed in the layer closest to the heat sink (for best heat dissipa- tion), and the cache memories are stacked in the remain- ing layers [4, 17, 26]. Our topology adopts the one-hop router design in vertical vias , and replaces the level 2D mesh with a network of long links connecting nodes that are at least m mesh-hops away, where m is a design pa- rameter. The mesh for the core layer is preserved for short distance communication less than m hops. In such a topol- ogy, communication that requires more than m horizontal hops will leverage the long physical wire and vertical links to reach destination, achieving low total hop count. Long- range links have been used on-chip for improving the per- formance of critical paths . Long links have also been inserted into an application-speciﬁc 2D mesh to reduce its average packet hop count . Although the main chal- lenges in using long links are 1) they may limit the clock frequency of the network; and 2) they may consume higher power than shorter links, we demonstrate through our ex- periments that we still obtain positive gains.
The region of Adrar is located in the Algerian South, which is fed by power plants, wind and photovoltaic farms, however it’s not interconnected to the Algerian national grid, which involves many disturbances of the grid voltage. The industrial development of the region requires an interconnection with the national grid to explore renewable sources of energy and allow having sufficient power. The work carried out concerns the interconnection of the Adrar region with the entire Algerian national grid. A modelling, a control and a real time analysis were realized for various scenarios. A FACTS device in shunt mode with an optimal location has controlled the improvement of the voltage of the interconnected grid. Keywords: load flow, voltage control, SVC (static var compensator), electrical grid, decentralized production, Interconnection grid, real-time.
flow of chilled air for cooling . Inefficient cooling only exacerbates the energy efficiency problems that plague the current datacenters. These problems are of- ten worse in small and mid-size datacenters with hundred to a few thousands of individual servers in educational institutions and private enterprises as these are designed and deployed in an ad-hoc manner often leading to structural and func- tional heterogeneity making regular systematic design impossible. To address these common design issues faced by wired or cabled datacenters wireless datacenter ar- chitectures are being investigated as a promising alternative. The capability of the unlicensed 60GHz wireless band to deliver very high communication rates has led to the development and approval of the IEEE 802.11ad wireless local area network (WLAN) standard . Therefore, recently proposed designs leverage newly devel- oped technologies in the unlicensed 60GHz wireless band for wireless DCNs  . Advancements in the 60GHz technologies enable the transceivers to consume low power, some even in the milliwatt range  , and establish multi-gigabit com- munication channels . Directional horn antennas  as well as more recently developed phased arrays of antennas in the 60GHz bands  can provide high directional gains and beam steering capability between wireless transceivers. Us- ing such antennas, the 60GHz channels can exhibit spatial re-usability, allowing multiple concurrent links reusing frequency bands to be formed within the same datacenter. The low power consumption combined with the ability to form concur- rent multi-gigabit channels makes these transceivers ideal for use in power-efficient wireless DCNs.
As a simple element we understand the artificial equivalent of a neuron that is known as computational neuron or node. These are organized hierarchically by layers and are interconnected between them just as in the biological nervous systems. Upon the presence of an external stimulus the artificial neural network generates an answer, which is confronted with the reality to determine the degree of adjustment that is required in the internal network parameters. This adjustment is known as learning network or training, after which the network is ready to answer to the external stimulus in an optimum way.
Each node has an external network interface to connect the IP core to the NoC. The external IP core can act as a packet source and/or as a packet destination (sink) depending on the simulated scenario. In our simulations, each source IP core generates packets and sends them to other IP cores. Each packet has three 32-bit flits(flow control unit, flit). The first (head) flit of a packet is sent to the routing mechanism of the node, and then transferred on the output of the target channel (if next node input channel is room). Once the head flit has been processed by the routing element of a node, a switching mechanism is defined to forward all immediately following packet-flits to the outgoing links of the target path to the destination node. We changed the flit rate injection from 0.05 flit/cycle/node to 0.5 flit/cycle/node. Each input channel consists of 8 flits fifo buffer. Each output channel consists of one flit buffer. The clock frequency of NoC is 1GHz.
Today is the era of parallel processing and building of multiprocessor system with hundred processors is feasible. Interconnection Networks (INs) play a major role in the performance of modem parallel computers. A vital component of these systems is the InterconnectionNetwork (IN) that enables the processor to communicate themselves or with memory units . Many aspects of INs, such as implementation complexity, routing algorithms, performance evaluation, fault-tolerance, and reliability have been the subjects of research over the years. There are many factors that may affect the choice of appropriate interconnectionnetwork for the underlying parallel computing environment. Though crossbar is the ideal IN for shared memory multiprocessor, where N inputs can simultaneously get connected to N outputs, but the hardware cost grows astronomically . Multistage Interconnection Networks
CCITT Rec. X.660 | ISO/IEC 9834-1 defines procedures for registration to meet OSI environment requirements for assignment of unambiguous names (e.g. object identifiers as specified in ITU-T Rec. X.680 | ISO/IEC 8824-1, Distinguished Names as specified in ITU-T Rec. X.501 | ISO/IEC 9594-2) to objects (distinguishable entities). These registration procedures are generally applicable to registration independent of the type of object involved. In particular, CCITT Rec. X.660 | ISO/IEC 9834-1 defines the registration-hierarchical-name-tree, which is a tree whose nodes correspond to objects that are registered and whose non-leaf nodes may be registration authorities. CCITT Rec. X.660 | ISO/IEC 9834-1 also defines procedures for the delegation of authority for the assignment of names in order to ensure that names are unambiguous.
Existing research has proposed some networks that are variations of the hypercube. These variants include the Exchanged Hypercube , the Gaussian Hypercube , and the Reduced Hypercube . They are defined by removal of a portion of the n-cube’s links while attempting to minimize performance degradation. Reduction of link complexity invariably makes the network more cost effective as it scales up. Nevertheless, some usefulness of a richer connectivity disappears. Routing becomes a serious problem, particularly when faulty components exist. Most hypercube-based interconnection networks are proposed in the literatures [12,13,14,15,16] suffer from similar size scalability problems. The Optical Multi-Mesh Hypercube (OMMH)  is a network that combines the positive features of the hypercube with those of a mesh. The OMMH can be viewed as a two-level system: a local connection level representing a set of hypercube modules and a global connection level representing the mesh network connecting the hypercube modules. The Spanning Multi-channel Linked Hypercube (SMLH) possesses a constant degree and a constant diameter while preserving many properties of the hypercube. Nevertheless, the Routing of two scalable network becomes more complex than the hypercube.
The figure 4 shows the Reconfigurable RISC Network processor (R2NP) architecture . R2NP is generally used as a base for developing or design of our reconfigurable crossbar switch architecture. Thus, design of our reconfigurable crossbar switch was based on the R2NP in network processor. Reconfigurable crossbar switch shown in figure 1, has mainly three blocks: (1) connection matrix, where all the topologies are implemented; (2) decoder, that converts there configurable bits for a matrix bits set and (3) pre-header analyzer. Network processor can add this third block in the packet with the output destination. Reconfigurable crossbar switch (RCS) uses reconfiguration bits to implement the topology in the space
In selection only the fittest species can survive, breed and pass their genes to the next generation. The proposed method uses the Roulette Wheel selection algorithm for selecting individuals with a probability proportional to the fitness. The network reliability is computed using the method . So the initial population taken for the example network (Figure 1) is given in Table I:
Aided Design (CAD) tools for RCs must perform three interrelated tasks : (1) Partition the computation into several fragments and map them to the various FPGAs; (2) Determine the control signal settings for the interconnection blocks so the signals among the FPGAs are appropriately routed; and, (3) Assign the interface signals of design fragments inside each FPGA to its pins so that the pin assignment is compatible with the configuration of the interconnectionnetwork. These are refereed to as the problems of partitioning, interconnect synthesis and pin-assignment respectively. This paper addresses the latter two problems.
Table 2 shows the total electrical resistance of each test vehicle. By forming an electrical conduction path with a metallurgical interconnection, the solderable ICA-based interconnection was stable, and acquired excellent electrical characteristics. The average total electrical resistance was 2 0:063 . On the other hand, in case of QFP intercon- nection formed by using ICA without reductant, a stable electrical characteristic could not obtain because no metal- lurgical interconnections were formed. These results showed that the QFP interconnection with solderable ICA contained reductant has a good electrical property due to the metal- lurgical interconnection formed by the coalesced and wetted LMPA ﬁllers rather than by the physical/mechanical bond- ing method of traditional ICAs. In the hybrid interconnection process using the solderable ICA, ICA facilitates the wetting and coalescence characteristics of the LMPA ﬁllers to form a stable metallurgical network for electrical conduction while also forming an ICA joint providing adhesion like a conventional ICA process.