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Packet Switching & the Client Server Model
The internet - The internet is a global system of connected computer networks that run the
standard internet protocol suite (TCP/IP)
The World Wide Web - An internet accessed system of interactive hypertext documents. The
WWW contains large amounts of data and multimedia.
Circuit Switching Network - Circuit switching networks are used when there is a
permanent/semi-permanent connection between fixed computers that will be performing
predictable and unchanging tasks over a long period of time until the connection is
terminated.
Network Interface Controller - NEC is the physical later of the data link connection and
encompasses the hardware side of the network. These include Ethernet connections
which is the standard for data transfer.
Intranet - Networking that occurs within a business or organisational environment which
offers services to client computers on a WAN/LAN system which allows for remote access
as well as Ethernet data transfer.
Router - Routers are devices that allow for interconnection between two or more computer
networks which allow for packet exchange. These are used for wireless LAN and NEC
connection to WAN internet connection.
Packet Switching - Packet switching is the transit of smaller “packets” of data to share over
networks. This is the primary way data is transferred via the internet. The individual
packets will be usually be transported over a variety of nodes such as network adapters,
switches, routers before reaching their destination.
Ping - This is the time taken for a packet to travel from the sender to the receiving device.
Ping is primarily influenced by factors such as distance but whether the connections are
fibre or coaxial as well as traffic and rerouting due to disruptions in the network can also
determine the ping. Ping can be tested using the cmd ping command to test how long it
takes for a packet to travel to another device by its IP address in milliseconds.
Trace - Trace commands in cmd are used to determine the hops taken by a packet
between different nodes before it reaches its destination. This can reveal if there is a
reroute or other obstacle on the path.
Server - A server is a system program used to serve clients in a network. Servers can be
dedicated hardware or any computer and run sever software such as a specially designed
operating system to deliver numerous services to the connected clients. These roles
include file sharing, websites, printing, game hosting and other services.
Client - In the server client model the client is the receiving system or user of a server and
its available services.
Peer to Peer - Peer to peer or P2P is a networking model that means all clients share an
equal role in handling workloads. Resources and computing power are shared. This does
not require a central server to coordinate the network and is common for large internet
file sharing such as torrenting online.
Cloud - Cloud computing is a development that is becoming increasingly important for
businesses and personal users. The cloud refers to servers being based in multiple
locations which can be distributed globally and accessed via an internet connection. This
is used commonly for file storage and sharing by companies which can offer paid services
to use them.
What are the advantages and disadvantages to a student in using Cloud Computing?
For a student, cloud computing Is helpful because it allows for file access from any device
with an internet connection as well as being remote meaning it cannot be lost in the way
a portable, removable drive can be. Also cloud storage can be large enough for most
users when still being used as a free service and costs are usually reasonable for large
amounts of data. Users can also be fairly confident that their data will be secure due to
usually professional management and security on the server if it is owned by a large
company.
Disadvantages of cloud computing for a student are that the service requires an internet
connection to be accessed which may not always be possible. Also cloud servers are
dependent on the internet of another country which may have different data protection
laws to the client. If the internet or server goes down in this country then files cannot be
accessed and they could be lost or damaged. Other disadvantages include not knowing
where the data actually is and privacy policies set up by the host could be considered too
intrusive.
Describe the process involved in a web server delivering a web page to a client.
A client requests the website hypertext files using a DNS to find the IP of a website stored
on a DNS server. The MAC addresses of the devices are confirmed and data is then split
in to packets which are assigned a port number as well as to and from addresses. The
packets are sent via nodes on the internet until they are rearranged back to normal at the
destination. A message confirms the arrival of the packets to the sender. The receiving
client’s computer then interprets the hypertext file as a website.
Describe a situation where having a single server and many client model might not
work too well.
This type of network would not be effective in a situation such as a WAN large file sharing
site which will be required to send very large amounts of data to a very large amount of
users constantly over the internet. In this situation the peer to peer model would be more
effective due to its sharing of computing power and resources.
Explain how layering (OSI or TCP/IP) in networking is an example of the divide and
conquer approach?
The OSI and TCP/IP are examples of the divide and conquer approach due to how they
both can be explained using abstraction to split the process into its most important
phases. The OSI is used to walk through the process of network communication with a
standardisation of the steps required (Application, presentation, session, transportation,
network, data link and physical.) The TCP/IP is used to layout the principle of
internet/world wide web communication (Application, transport, internet, network
interface and hardware.)
Describe the difference between a circuit switching and packet switching network.
What are the advantages and disadvantages of each type of network?
Circuit switching is advantageous in situations where there is little need to modify the
connection or the nature of the contents of storage servers at any time. This system is
best suited to 2 fixed computers networked to each other only and is excellent when
repetitive batches of data are required to be sent on a secure and unchangeable network.
This networking method is secure because no other nodes or clients are served other
than those chosen to be until the network is terminated. This system becomes limited
when the format or nature of the data changes to a point where it requires a different
type of networking such as oversize files. Also if a new destination or node path is
required or due to a disruption then this cannot be completed due to the nature of circuit
switching networks and their lack of ability to reroute or change circuit.
Packet switching is effective when a more dynamic and adaptable solution is required to
serve various clients in different locations. Packet switching is far better at handling
disruptions and down nodes due to rerouting. This network suffers from being less secure
due to unknown users, data and varying paths which could allow for malicious files or
clients.