16-08-2011, 10:22 AM
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Building a Simple Network
INTRODUCTION TO NETWORKS
Network
“ ... communication system for connecting end-systems”
End-systems i.e. set of devices(nodes).
They can be:
PCs
Workstations
Dedicated computers
Network components
Networking
Data Flow
LAN - Local Area Network
connects computers that are physically close together ( < 1 mile).
high speed
multi-access
Implementations:
Ethernet: 10 Mbps, 100Mbps
Token Ring: 16 Mbps
MAN - Metropolitan Area Network
Larger than a LAN and smaller than a WAN
- Typically covers an area of between 5 and 50 km range.
It is not generally owned by a single organization.
often acts as a high speed network to allow sharing of regional resources.
Implementations:
coaxial cable
microwave
WAN - Wide Area Network
connects computers that are physically far apart.
typically slower than a LAN.
typically less reliable than a LAN.
point-to-point
Implementations:
Telephone lines
Satellite communications
OSI Model
The Seven Layers of the OSI Model
The Seven Layers of the OSI Model (Cont.)
The Seven Layers of the OSI Model (Cont.)
The Seven Layers of the OSI Model (Cont.)
The Seven Layers of the OSI Model (Cont.)
The Seven Layers of the OSI Model (Cont.)
The Seven Layers of the OSI Model (Cont.)
Connecting Networks
Repeater: physical layer
Bridge: data page link layer
Router: network layer
Gateway: network layer and above.
Repeater
Copies bits from one network to another
Does not look at any bits
Allows the extension of a network beyond physical length limitations
Bridge
Copies frames from one network to another
Can operate selectively - does not copy all frames (must look at data-link headers).
Extends the network beyond physical length limitations.
Routers: Operate at the Network Layer
Broadcast control
Multicast control
Optimal path determination
Traffic management
Logical addressing
Connects to WAN services
Switches
CONCLUSION
On completion of this , you will be able to perform the following tasks:
Describe how data traffic is exchanged between source and destination devices
Identify the roles and functions of a repeater, bridge, switch, and router, and where they best fit in the network
