Friday, 9 March 2012

Network equipment, Protocol and Cabling

Networking hardware includes all computers, peripherals, interface cards and other equipment needed to perform data-processing and communications within the network.
A file server stands at the heart of most networks, very fast computer, large amount of RAM and storage space, a fast network interface card, network operating system software resides on this computer, along with any software applications and data files that need to be shared.
User computers that are connected to a network are called workstations.  Configured with a network interface card, networking software, and the appropriate cables, does not necessarily storage capability, files can be saved on the file server. Almost any computer can serve as a network workstation.
NETWORK HARDWARE provides the physical connection between the network and the computer workstation.  Major factor in determining the speed and performance of a network is most NICs are internal, with the card fitting into an expansion slot inside the computer. Some computers, such as Mac Classics, use external boxes which are attached to a serial port or a SCSI port. Laptop computers - built-in NIC or network cards that slip into a PCMCIA slot.
Token Ring Cards
• Token Ring network cards look similar to
Ethernet cards
• One visible difference is the type of connector on the back end of the card. Generally have a nine pin DIN type connector to attach the card to the network cable.

Protocol (communications protocol) standards that specifically address how the devices on a network communicate, for example,
– How the data is packaged for transmission
– How receiving devices acknowledge signals from sending devices,
-How errors are detected and handled.
Logical topologies are bound to network protocols and describe how data is moved across the network.
• TCP/IP and WAP for internet
• Wi-Fi for wireless networks
• Bluetooth, for short range wireless network
• Ethernet, Local Talk, Token ring for wired networks
developed by IBM in the mid-1980s.
• access method involves token-passing.
• the computers are connected so that the signal travels around the network from one computer to another in a
Protocol : Token Ring, logical ring. A single electronic token moves around the ring from one computer to the next. If a computer does not have information to transmit, it simply passes the token on to the next workstation. If a computer wishes to transmit and receives an empty token, it attaches data to the token. The token then proceeds around the ring until it comes to the computer for which the data is meant- the data is captured by the receiving computer.
Cable is the medium through
which information usually moves
from one network device to
another .
• In some cases, a network will utilize only one type of cable, other networks will use a variety of cable types
• Several types of cable are commonly used with LANs.

The standard connector for unshielded twisted pair cabling is an RJ-45 connector. A disadvantage of UTP is that it may be susceptible to radio and electrical frequency interference.

STP is a type of cable consists of two individual wires wrapped in a foil shielding to help provide a more reliable data communication.
Shielded Twisted Pair (STP) Cable
• suitable for environments with electrical interference;
• however, the extra shielding can make the cables quite bulky.
• often used on networks using Token
Ring topology.
Software that controls a network and its message (e.g. packet) traffic and queues, controls access by multiple users to network resources such as files, and provides for certain administrative functions, including security. coordinate the activities of multiple computers, across a network,  acts as a director to keep the network running, smoothly. 10
• The two major types of network
operating systems are: :
Peer to Peer
Peer to Peerresources
– Peer-to-– Client/Server
• In a peer-to-peer network, all computers are
considered equal; they all have the same abilities
to use the resources available on the network
• allow users to share resources and files located
on their computers and to access shared
found on other computers.
• do not have a file server or a centralized management source
• designed primarily for small to medium local area networks.
• AppleShare and Windows for Workgroups are examples of programs that can function as peer to peer network operating systems.

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