Networking Basics
Networking: An Overview:
A network is a group of interconnected systems which share services and interact with each other by means of a shared communication link.
These systems can be located anywhere.
Network is often classified according to its geographical size.
Benefits of networking:
Goal of having networking environment is to provide services and to reduce the equipment
costs. The primary reasons for networking PC's are as follows:
- Sharing printers and other devices
- Providing Distributed Computing.
- Sharing Files
- Centralized administration of resources
- Security of Resources.
- Personal communications (like e-mail, chat, audio/video conferencing)
- World Wide Web ... and many other uses
Networking Basics:
- Network consist many components:
– Hardware
» Transmission Facilities
»Access Devices
»Devices that repeat transmitted signals
– Software
»Protocol that define and regulate the way two or more device communicate.
»Drivers, that guide the functionality of Network Interface Card (NIC)
»Communication Software.
Networking Basics: Hardware:
- Transmission Facilities
– Are the media used to transport network’s signals to their destination.
» Coaxial Cable, Twisted Pair, Fiber- Optic
- Access Devices
– Is known as Network Interface Card (NIC), and is responsible for
» Properly formatting data so that it can be accepted in the network
» Placing data on the network
» Accepting transmitted data that’s addressed to it.
- Repeaters/Hubs
– Accepts transmitted signals, amplify it and puts them back on the network
Network Basics : Software:
- Protocol
– Are standards that allow computer to communicate.
– Define how computer identify one another on a network
– How information be processed once it reach its final destination.
– Define procedure for handling lost or damaged packets.
- Device Drivers
– Is a hardware level program that control NIC
– NIC, provide an interface for its host’ operating system
- Communication Software
– That enable the users to communicate and share resources
» Windows Explorer, WWW, Telnet, FTP
Multiaccess vs. Point-to-point:
- Multiaccess means shared medium.
– many end-systems share the same physical communication resources (wire, frequency, ...)
– There must be some arbitration mechanism. - Point-to-point
– only 2 systems involved
– no doubt about where data came from !
LAN - Local Area Network:
- Connects computers that are physically close together ( < 1 mile).
– high speed
– multi-access - Technologies:
– Ethernet 10 Mbps, 100Mbps
– Token Ring 16 Mbps
– FDDI 100 Mbps
WAN -Wide Area Network:
- Connects computers that are physically far apart. “long-haul network”.
– Typically slower than a LAN.
– Typically less reliable than a LAN.
– Point-to-point - Technologies:– Telephone lines
– Satellite communications
MAN - Metropolitan Area Network:
- Larger than a LAN and smaller than a WAN
- Example: campus-wide network
- Multi-access network
- Technologies:
– Coaxial cable
– Microwave (Wireless Technology)
Internetwork:
- Connection of 2 or more distinct (possibly dissimilar) networks.
- Requires some kind of network device to facilitate the connection.
Network Models:
- Using a formal model allows us to deal with various aspects of Networks abstractly.
- We will look at a popular model (OSI reference model).
- The OSI reference model is a layered model.