CH 1 Introduction to Computer Networking (Part 2)
Question 5:-list Difference between
osi and tcp/ip model.
OSI(Open System Interconnection)
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TCP/IP(Transmission Control Protocol / Internet
Protocol)
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1. OSI is a
generic, protocol independent standard, acting as a communication gateway
between the network and end user.
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1. TCP/IP
model is based on standard protocols around which the Internet has developed.
It is a communication protocol, which allows connection of hosts over a
network.
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2. In OSI
model the transport layer guarantees the delivery of packets.
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2. In TCP/IP
model the transport layer does not guarantees delivery of packets. Still the
TCP/IP model is more reliable.
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3. Follows
vertical approach.
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3. Follows
horizontal approach.
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4. OSI model
has a separate Presentation layer and Session layer.
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4. TCP/IP
does not have a separate Presentation layer or Session layer
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5. OSI is a
reference model around which the networks are built. Generally it is used as
a guidance tool.
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5. TCP/IP
model is, in a way implementation of the OSI model.
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6. Network
layer of OSI model provides both connection oriented and connectionless
service.
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6. The
Network layer in TCP/IP model provides connectionless service.
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7. OSI model
has a problem of fitting the protocols into the model.
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7. TCP/IP
model does not fit any protocol
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8. Protocols
are hidden in OSI model and are easily replaced as the technology changes.
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8. In TCP/IP
replacing protocol is not easy.
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9. OSI model
defines services, interfaces and protocols very clearly and makes clear
distinction between them. It is protocol independent.
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9. In
TCP/IP, services, interfaces and protocols are not clearly separated. It is
also protocol dependent.
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10. It has 7
layers
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10. It has 4
layers
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Question 6:-Discuss throughput.
Throughput
is a measure of how many units of information a system can process in a given
amount of time. It is applied broadly to systems ranging from various aspects
of computer and network systems to organizations. Related measures of system
productivity include , the speed with which some specific workload can be
completed, and response time, the amount of time between a single interactive
user request and receipt of the response.
Historically, throughput has been a measure
of the comparative effectiveness of large commercial computers that run many
programs concurrently. An early throughput measure was the number of batch jobs
completed in a day. More recent measures assume either a more complicated
mixture of work or focus on some particular aspect of computer operation. Units
like "trillion floating-point operations per second (TeraFLOPs or TFLOPS)"
provide a metric for comparing the cost of raw computing over time or by
manufacturer. A benchmark can be used to measure throughput. In data
transmission, network throughput is the amount of data moved successfully from
one place to another in a given time period, and typically measured in bits per
second (bps), as in megabits per second (Mbps) or gigabits per second (Gbps).Likewise, in storage systems, throughput refers to either the amount of data that can be received and written to the storage medium or read from media and returned to the requesting system, typically measured in bytes per second (Bps). It can also refer to the number of discrete input or output (I/O) operations responded to in a second (IOPS).
Throughput applies at higher levels of the IT infrastructure as well. Databases or other middleware can be discussed in terms of "transactions per second" (TPS); Web servers can be discussed in terms of page-views per minute.
Throughput also applies to the people and organizations using these systems: Independent of the TPS rating of its help desk software, for example, a help desk has its own throughput rate that includes the time staff spend on developing responses to requests.
Local Area Network
A local area network, or LAN, consists
of a computer network at a single site, typically an individual office
building. A LAN is very useful for sharing resources, such as data storage and
printers. LANs can be built with relatively inexpensive hardware, such as hubs,
network adapters and Ethernet cables.
The smallest LAN may only use two computers, while
larger LANs can accommodate thousands of computers. A LAN typically relies
mostly on wired connections for increased speed and security, but wireless
connections can also be part of a LAN. High speed and relatively low cost are
the defining characteristics of LANs.
LANs are typically used for single sites where people
need to share resources among themselves but not with the rest of the outside
world. Think of an office building where everybody should be able to access
files on a central server or be able to print a document to one or more central
printers. Those tasks should be easy for everybody working in the same office,
but you would not want somebody just walking outside to be able to send a document
to the printer from their cell phone! If a local area network, or LAN, is
entirely wireless, it is referred to as a wireless local area network, or WLAN.
metropolitan area network (MAN)
A metropolitan area network (MAN) is a network that
interconnects users with computer resources in a geographic area or region
larger than that covered by even a large local area network (LAN) but smaller than
the area covered by a wide area network (WAN).
The term is applied to the interconnection of
networks in
a city into a single larger network (which may then also offer efficient
connection to a wide area network). It is also used to mean the interconnection
of several local area networks by bridging them with backbone lines. The latter usage is also
sometimes referred to as a campus network.
Examples of metropolitan area networks of various
sizes can be found in the metropolitan areas of London, England; Lodz, Poland;
and Geneva, Switzerland. Large universities also sometimes use the term to
describe their networks. A recent trend is the installation of wireless MANs.
Wide Area Network
A wide area network, or WAN, occupies a
very large area, such as an entire country or the entire world. A WAN can
contain multiple smaller networks, such as LANs or MANs. The Internet is the
best-known example of a public WAN.
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