Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Backpressure routing wikipedia , lookup
Distributed operating system wikipedia , lookup
Cracking of wireless networks wikipedia , lookup
Piggybacking (Internet access) wikipedia , lookup
Computer network wikipedia , lookup
Network tap wikipedia , lookup
Recursive InterNetwork Architecture (RINA) wikipedia , lookup
IEEE 802.1aq wikipedia , lookup
Peer-to-peer wikipedia , lookup
CS405 Parallel Computing BS-Computer Science (SSUET) LECTURE 7: INTERCONNECTION NETWORKS – II HYPERCUBE NETWORKS: Constructing an N-Dimensional Hypercube For dimension N+1, just create two hypercube of dimension N, and connect analogous vertices. N Nodes: 2N Links per Node: N Longest Path: N Dimensions: 3 2 3=8 3 3 3-D Hypercube Node Numbering Each node must differ from an adjacent node by at most one binary digit. Three-Dimensional Hypercube Adjacent nodes differ by one binary digit. Example in Node Numbering Question: In a four-dimensional hypercube, what nodes connect to node 12? Answer: 4, 8, 13, and 14 Solution: First Convert to Binary: Node 12 = 1100 in Binary Then apply the exclusive-OR (XOR) operation with a "1" digit in each of the four positions Lecturer: Engr. Muhammad Nadeem Page 1 CS405 Parallel Computing 1100 1100 1100 1100 XOR XOR XOR XOR 0001 0010 0100 1000 = = = = 1101 1110 1000 0100 BS-Computer Science (SSUET) or 13 or 14 or 8 or 4 The resulting values are the nodes that should link directly to node 12. Mesh Networks: 1. Mesh network is a type of networking where each node must not only capture and disseminate its own data, but also serve as a relay for other nodes, that is, it must collaborate to propagate the data in the network. 2. A mesh network can be designed using a flooding technique or a routing technique. 3. When using a routing technique, the message is propagated along a path, by hopping from node to node until the destination is reached. Lecturer: Engr. Muhammad Nadeem Page 2 CS405 Parallel Computing BS-Computer Science (SSUET) 4. To ensure all its paths' availability, a routing network must allow for continuous connections and reconfiguration around broken or blocked paths, using self-healing algorithms. 5. The self-healing capability enables a routing based network to operate when one node breaks down or a connection goes bad. As a result, the network is typically quite reliable, as there is often more than one path between a source and a destination in the network. BINARY TREE NETWORKS: BUTTERFLY: A Butterfly network is made of (n + 1)*2n processors organized into n+1 rows, each containing 2n processors. Lecturer: Engr. Muhammad Nadeem Page 3 CS405 Parallel Computing BS-Computer Science (SSUET) Rows are labeled 0 … n. Each processor has four connections to other processors (except processors in top and bottom row). Processor P(r, j), i.e. processor number j in row r is connected to P(r-1, j) and P(r-1, m) Where m is obtained by inverting the rth significant bit in the binary representation of j. PYRAMID A pyramid consists of (4d+1 – 1)/3 processors organized in d+1 levels so as: Levels are numbered from d down to 0 There is 1 processor at level d Every level below d has four times the number of processors than the level immediately above it. Note the connections between processors. Lecturer: Engr. Muhammad Nadeem Page 4 CS405 Parallel Computing BS-Computer Science (SSUET) Pyramid interconnection can be seen as generalization of the ring – binary tree network, or as a way of combining meshes and trees. STAR NETWORK: A generalized star interconnection network has the property that for a given integer N, we have exactly N! Processors. Each processor is labeled with the permutation to which it corresponds. Two processors Pi and Pj are connected if the label I can be transformed into label j by switching the first label symbol of I with a symbol of j (excluding 1st symbol of j) Below we have a star network for N=4, i.e. a network of 4! = 24 processors. Example: Processors labeled 2134 and 3124 are connected with two links. NOTE: The whole idea is to make each node a center node of a small star! Lecturer: Engr. Muhammad Nadeem Page 5 CS405 Parallel Computing BS-Computer Science (SSUET) Metrics of Interconnection Network: Degree: No. of links per node. Diameter: Longest distance between two nodes in the network. Bisection: Min no. of wire cuts to divide the network in 2 halves. Cost: No. of links and switches. Lecturer: Engr. Muhammad Nadeem Page 6