The document discusses several common network topologies. It describes star, ring, mesh, bus, and hybrid topologies. For each topology, it provides details on the logical structure and flow of data through the network. It also lists the advantages and disadvantages of each topology type. Finally, it briefly defines the key differences between local area networks (LANs) and wide area networks (WANs) in terms of geographic distribution, data rates, error rates, communication links, ownership, and communication costs.

1. Network Topologies and
Types

2. Topology
● The way in which the computers or other devices
that need to communicate are inter-linked together – Topology
● Choice of topology depends on following factors
○ Desired Performance of the system
○ Desired Reliability of the system
○ No. of nodes(computer or devices) in the system
○ Cost of maintaining the network
○ Routing information from one node to another

3. Star Topology
● It has multiple nodes connected to host
node
● Nodes in the network are interconnected
to each other through host node
● They (node) can communicate only
through host node
● The entire network is control by host node
● The logical path for the communication
between two node is define by host node

4. Star Topology
● Advantage
○ It has minimal line cost because only n-1 lines
are required for connecting n nodes
○ Adding new node in network delay the
transmission
○ If host node fails network is down
● Dis – Advantage
○ Network depends on host node

5. Ring Topology
● It is represented as a circular or ring network
● Each node has two communicating
subordinates
● No master or host node to control the network
● A node receives data from one of its two
adjacent nodes
● Data is utilized if it is for it(node), otherwise
passes to the next node.

6. Ring Topology
● Advantage
○ No central node, to control the network or
routing decisions
○ It is more reliable than star topology if one of
node is fail than the alternative routing is
possible
● Dis Advantage
○ Addition of node in network increases
communication delay
○ Requires special control software than star
topology

7. Mesh Topology
● It is completely connected network
● Each node has Personal physical line for
connecting to all other node
● Each Node has a direct link – Point-to-Point
link
● Control is distributed with each node

8. Mesh Topology
● Advantage
○ It is very reliable because failure of any node
doesn't affects the network
○ Each node of the network need not have
individual routing capability
○ Communication very fast between two nodes
● Dis Advantage
○ It is most expensive network

9. Bus Topology
● All nodes in network share single
transmission
medium i.e same communication channel
● It appends destination address to message
and checks whether channel is free
● Also known as ‘multipoint’ or ‘multidrop’ or
‘broadcast’ network

10. Bus Topology
● Advantage
○ It helps in reducing the number of physical lines
○ Failure of any node doesn’t affects the network
○ Adding of new nodes to the network is easy
● Dis-Advantage
○ All the nodes in a network must have good
communication and decision making capability
○ If the shared communication line fails, the entire
network fails

11. Hybrid Topology
● Combination of two or more different
network
topologies – Hybrid Topology
● Different network Topologies have their own
advantages and limitation
● A pure star or ring topology is rarely used

12. Types of Network
Characteristics LAN WAN
Geograhpic Only few km Extend upto
Distribution thousand km
Data Rate Much higher rate 1200 bps to 2
than WAN (10 Mbps
mbps) to1 (gbps)
Error Rate Fewer Higher
Communication Twisted pair, Telephone lines,
Link coaxial cable and microwave link and
fiber optic satellite channels
Ownership Single Different
Organization Organization
Communication Cost Negligible Costly