Management Information System
Syed. Sajid. Hussain.
MINHAJ UNIVERSITY Gulberg Campus Lahore.
A protocol is a set of rules that governs the communications between computers on a network. These
rules include guidelines that regulate the following characteristics of a network: access method, allowed
physical topologies, types of cabling, and speed of data transfer.
• IP - Internet Protocol
IP assigns a unique number to every network device in the world, which is called IP address.
• TCP - Transmission Control Protocol
TCP provides a reliable stream delivery and virtual connection service to applications through the use of
sequenced acknowledgment with retransmission of packets when necessary.
Several physical data-transmission media are available to connect together the various devices on a
network. One possibility is to use cables.
There are many types of cables, but the most common are:
1. Coaxial cable
2. Twisted pair
3. Optical fibre
1. Coaxial Cable:
Coaxial cable has long been the preferred form of cabling, for the simple reason that it is inexpensive
and easily handled (weight, flexibility, ...).
A coaxial cable is made of up a central copper wire (called a core) surrounded by an insulator, and then a
braided metal shield.
2. Twisted Pair Cabe:
In its simplest form, twisted-pair cable consists of two copper strands woven into a braid and covered
• Twisted Pair Connectors:
Twisted pair cable is connected using an RJ-45 connector. This connector is similar to the RJ-11 used in
telephony, but differs on a few points: RJ-45 is slightly larger and cannot be inserted into an RJ-11 jack.
In addition, the RJ-45 has eight pins while the RJ-11 has no more than six, usually only four.
3. Fibre Optics:
Optical fibre is a cable advantages:
• Immune to noise
• Low attenuation
• Tolerates data rates on the order of 100 Mbps
• Bandwidth from tens of megahertz to several gigahertz (monomode fibre)
Fibre optic cabling is particularly suited to links between central link between several buildings as it
allows connections over long distances from several kilometres. Furthermore, this type of cable is very
secure as it is extremely difficult to tap in to such a cable.
The physical topology of a network refers to the configuration of cables, computers, and other
Types of Network Topologies:
• Star Topology
• Ring Topology
• Bus Topology
• Tree Topology
• Mesh Topology
Many home networks use the star topology. A star network features a central connection point called a
"hub" that may be a hub, switch or router. Devices typically connect to the hub with Unshielded Twisted
Pair (UTP) Ethernet. a star network generally requires more cable, but a failure in any star network cable
will only take down one computer's network access and not the entire LAN.
• Easy to install and wire. • Requires more cable length than a linear
• No disruptions to the network then topology.
connecting or removing devices. • If the hub or concentrator fails, nodes
• Easy to detect faults and to remove parts. attached are disabled.
• More expensive than linear bus topologies
because of the cost of the concentrators.
In a ring network, every device has exactly two neighbors for communication purposes. All messages
travel through a ring in the same direction (either "clockwise" or "counterclockwise"). A failure in any
cable or device breaks the loop and can take down the entire network.
Ring topologies are found in some office buildings or school campuses.
A single cable, the backbone functions as a shared communication medium that devices attach or tap
into with an interface connector. A device wanting to communicate with another device on the network
sends a broadcast message onto the wire that all other devices see, but only the intended recipient
actually accepts and processes the message.
Ethernet bus topologies are relatively easy to install and don't require much cabling compared to the
alternatives. However, bus networks work best with a limited number of devices. If more than a few
dozen computers are added to a network bus, performance problems will likely result. In addition, if the
backbone cable fails, the entire network effectively becomes unusable.
• Easy to connect a computer or peripheral to • Entire network shuts down if there is a
a linear bus. break in the main cable.
• Requires less cable length than a star • Terminators are required at both ends of
topology. the backbone cable.
• Difficult to identify the problem if the
entire network shuts down.
• Not meant to be used as a stand-alone
solution in a large building.
Tree topologies integrate multiple star topologies together onto a bus. In its simplest form, only hub
devices connect directly to the tree bus, and each hub functions as the "root" of a tree of devices.
• Point-to-point wiring for individual • Overall length of each segment is
segments. limited by the type of cabling used.
• Supported by several hardware and software • If the backbone line breaks, the entire
venders. segment goes down.
• More difficult to configure and wire than
Mesh topologies involve the concept of routes. Unlike each of the previous topologies, messages sent on
a mesh network can take any of several possible paths from source to destination.
A mesh network in which every device connects to every other is called a full mesh partial mesh
networks also exist in which some devices connect only indirectly to others.
►Local Area Network◄
A local area network (LAN) is a network used for connecting a business or organisation's computers to
one another for
• Exchange information
• Access various services
A local area network usually links computers (or resources such as printers) using a wired transmission
medium (most frequently twisted pairs or coaxial cables) over a circumference of about a hundred
Hardware components of a local area network
A local area network is made of computers linked by a set of software and hardware elements. The
hardware elements used for connecting computers to one another are:
• Network Card:
This is a card connected to the computer's motherboard, which interfaces with the
physical medium, meaning the physical lines over which the information travels.
This is used to transform the signals travelling over the physical support into
logical signals that the network card can manipulate, both when sending and receiving data.
This is the element used to mechanically connect the network card with the
• Physical Medium:
This is the support (generally wired, meaning that it's in the form of a cable) used
to link the computers together. The main physical support media used in local area networks are:
• Coaxial cable
• Twisted pair
• Fibre optics
►Wide Area Network◄
A Wide Area Network ( WAN) is a computer network covering multiple distance areas, which may
spread across the entire world. WANs often connect multiple smaller networks, such as local area
networks (LANs) or metro area networks (MANs). The world's most popular WAN is the Internet. Some
segments of the Internet are also WANs in themselves.
The key difference between WAN and LAN technologies is scalability. WAN must be able to grow as
needed to cover multiple cities, even countries and continents. A set of switches and routers are
interconnected to form a Wide Area Network.
WANs are either point-to-point, involving a direct connection between two sites, or operate across
packet-switched networks, in which data is transmitted in packets over shared circuits. Point-to-point
WAN service may involve either analog dial-up lines, in which a modem is used to connect the
computer to the telephone line, or dedicated leased digital telephone lines, also known as "private lines."
The user of a WAN usually does not own the communications lines that connect the remote computer
systems; instead, the user subscribes to a service through a telecommunications provider. Unlike LANs,
WANs typically do not link individual computers, but rather are used to link LANs. WANs also transmit
data at slower speeds than LANs. WANs are also structurally similar to metropolitan area networks
(MANs), but provide communications links for distances greater than 50 kilometers.
►Metropolitan Area Network◄
A MAN is a relatively new class of network, it serves a role similar to an ISP, but for corporate users
with large LANs. There are three important features which discriminate MANs from LANs or WANs:
1. The network size falls intermediate between LANs and WANs. A MAN typically covers an area of
between 5 and 50 km diameter. Many MANs cover an area the size of a city, although in some cases
MANs may be as small as a group of buildings.
2. A MAN (like a WAN) is not generally owned by a single organization. The MAN, its
communications links and equipment are generally owned by either a consortium of users or by a
single network provider who sells the service to the users. This level of service provided to each user
must therefore be negotiated with the MAN operator, and some performance guarantees are
A MAN often acts as a high speed network to allow sharing of regional resources (similar to a large
LAN). It is also frequently used to provide a shared connection to other networks using a link to a WAN.