The design of network requires selection of a particular topology and an architecture for
the interconnection of network component.
Topology refers to the way the computers are physically connected into the network. The
network architecture includes the specifications of the components that can be connected to the
network. IBM’s Systems Network Architecture (SNA) is an example of vendor developed
network architecture. Such network architecture specifies network components such as
terminals, workstations, printers, cluster controllers, host computer and communications
controllers.
There area a number of network topologies. Of them ring, star and bus are popular network
topologies.
In a star network centralization of control over the network resources is easy. It is also
possible to network minicomputer or mainframe with other microcomputers and dumb terminals.
It eliminates single point failure of a common wire. If one of the host computers fails, it does not
usually affect the others in the network. But the hub becomes a central point of failure in a ring
network. If the host computer breaks down, the entire network breaks down.
Old Ethernet bus wiring is prone to cable failure. If the bus wiring connection is broken
at any point, the entire network fails.
the interconnection of network component.
Topology refers to the way the computers are physically connected into the network. The
network architecture includes the specifications of the components that can be connected to the
network. IBM’s Systems Network Architecture (SNA) is an example of vendor developed
network architecture. Such network architecture specifies network components such as
terminals, workstations, printers, cluster controllers, host computer and communications
controllers.
There area a number of network topologies. Of them ring, star and bus are popular network
topologies.
a) Star Topology:
In star network the nodes are connected to a central computer called the host computer.
The nodes cannot communicate directly. Each node can communicate with the host computer.
The host computer takes the message and routes it to the other node or nodes.
The nodes cannot communicate directly. Each node can communicate with the host computer.
The host computer takes the message and routes it to the other node or nodes.
possible to network minicomputer or mainframe with other microcomputers and dumb terminals.
It eliminates single point failure of a common wire. If one of the host computers fails, it does not
usually affect the others in the network. But the hub becomes a central point of failure in a ring
network. If the host computer breaks down, the entire network breaks down.
b) Ring Topology:
In a ring network the computers can communicate directly with each other and also with
the central computer. The nodes are connected to a line that is closed like a loop. The ring
network is more reliable than star network. Even if the central computer in the network fails, the
other computers can continue to communicate with each other.
the central computer. The nodes are connected to a line that is closed like a loop. The ring
network is more reliable than star network. Even if the central computer in the network fails, the
other computers can continue to communicate with each other.
c) Bus Topology:
A bus network configures computers to a single non-looping channel. The computers
connected to the network share the same bus or communication channel. Bus wiring is easy and
needs much less wring for small segments.
connected to the network share the same bus or communication channel. Bus wiring is easy and
needs much less wring for small segments.
at any point, the entire network fails.
d) Hybrid Network:
In most cases, instead of a single topology, a combination of topologies may be used for
greater flexibility and reliability. Hybrid network combines features of Star, Ring and Bus
network:
greater flexibility and reliability. Hybrid network combines features of Star, Ring and Bus
network:
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