CS621 Final Term Highlighted Handouts by Vaniza

CS 621 Final Term · Lecture No: 07 · Interconnection Networks:

“Interconnection networks provide mechanisms for data transfer between processing nodes or between processors and memory modules.”

Interconnects are made of switches and links. Provide efficient, correct, robust message passing between two separate nodes.

Local area network (LAN) – connects nodes in single building fast & reliable.

• Media: twisted-pair, coax, fiber
• Bandwidth: 10-100MB/s

Wide area network (WAN) – connects nodes across large geographic area.

• Media: fiber, microwave links,satellite channels
• Bandwidth: 1.544MB/s (T1), 45 MB/s (T3)

Interconnection networks are classified into two categories:

1) 2)

Static networks consist of point-to-point communication links among processing nodes and are also referred to as direct networks. Direct fixed links are established among nodes to form a fixed network.

Connections are established when needed. Dynamic networks are built using switches and communication links. Dynamic networks are also referred to as indirect networks.

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Communication links are connected to one another dynamically by the switches to establish paths among processing nodes and memory banks.

Classification of interconnection networks:

Control Strategy

Depending on where the decisions are made as well as on the number of measurements that are utilized to make the control decisions, these control strategies are classified into two categories:

i. Centralized ii.

Centralized

Set of tightly coupled programs executing on one or more computers which are interconnected through a network and coordinating their actions. The control function is distributed among different components in the system. Autonomous components. Mostly build using heterogeneous technology. System components may be used exclusively. Concurrent processes can execute. Multiple point of failure.

Switching Techniques:

“Switching is process to forward packets coming in from one port to a port leading towards the

Switches map a fixed number of inputs to outputs. The total number of ports on a switch is the degree of the switch. Switches may also provide support for internal buffering, routing and multicast. The cost of a switch grows as the square of the degree of the switch, the peripheral hardware linearly as the degree, and the packaging costs linearly as the number of pins. Nodes may connect to other nodes only, or to stations and other nodes. End devices are stations:

• Computer, terminal, phone, etc.