COMPUTER NETWORK | TOPIC 6 | SPECIALIST SERVERS

List all the different types of specialist server you can think of or find via the internet and books (e.g. mail server). Briefly  describe each one

1.       Application Server

o   Referred to as a type of middleware

o   Occupy a large chunk of computing territory between database servers and the end user and they often connect the two.

2.       Communication Server

o   Handles many common communications functions for the network, such as e-mail, fax, remote access, firewalls or internet services.

3.       Domain controllers/directory servers

o   Authenticates and authorizes computers and users to access resources within the logical domain

4.       Fax servers

o   A system installed in a local area network server that allows computer users who are attached to the LAN to send and receive fax messages

5.       File Servers

o   Stores network users’ data files

6.       Print servers

o   Manages the printers that are connected to the network and the printing of user documents on the network printers.

7.       Mail Server

o   Move and store mail over corporate networks via LANs and WANs and across the internet.

8.       Web Server

o   Serves static content to a web browser by loading a file from a disk and serving it across the network to a user’s browser.

o   This entire exchange is mediated by the browser and server talking to each other using HTTP.

·         http://www.webopedia.com/quick_ref/servers.asp

·         https://www.go4expert.com/articles/types-of-server-t325/

·         https://www.sqa.org.uk/e-learning/HardOSEss04CD/page_33.htm

COMPUTER NETWORK | TOPIC 5 | SEMINAR NOTES | PAIR

Patricia Jhem M. Panganiban

Patricia Denise C. Concepcion

Exercise 1:

Research Category 5, 5e and 6 Ethernet cables and write a report giving a brief outline of each category including the frequencies used.

Cat5: A Little Older, A Little Slower

Category 5 cabling, also known as Cat5, is an older type of network cabling. Cat5 cables were made to support theoretical speeds of 10Mbps and 100Mbps. You may be able to get gigabit speeds on a Cat5 cable, particularly if the cable is shorter, but it isn't always guaranteed.

Since Cat5 is an older type of cabling, you probably won't see them very much in the store, but you may have gotten some with an older router, switch or other networking device.

Cat5 has become obsolete in recent years, due to its limitations compared to Cat5E and Cat6 cables. Although the Cat5 cable can handle up to 10/100 Mbps at a 100MHz bandwidth (which was once considered quite efficient), the newer versions of Cat cables are significantly faster.

Cat5e: Faster with Less Interference

Category 5 enhanced cabling, also known as Cat5e, is an improvement on Cat5 cabling. It was made to support 1000 Mbps "gigabit" speeds, so in theory, it's faster than Cat5. It it also cuts down on crosstalk, the interference you can sometimes get between wires inside the cable. Both of these improvements mean you're more likely to get fast, reliable speed out of Cat5e cabling compared to Cat5.

Cat5E cable (which stands for “Cat5 Enhanced”) became the standard cable about 15 years ago and offers significantly improved performance over the old Cat5 cable, including up to 10 times faster speeds and a significantly greater ability to traverse distances without being impacted by crosstalk.

Cat6: Even Faster, But Not Super Necessary

Category 6 cabling is the next step up from Cat5e and includes a few more improvements. It has even stricter specifications when it comes to interference, and its capable of 10-Gigabit speeds in some cases. You probably won't use these speeds in your home, and the extra interference improvements won't make a huge difference in regular usage, so you don't exactly need to rush out and upgrade to Cat6. Bu

t, if you're buying a new cable, you might as well, since it is an improvement over its predecessor.

Cat6 cables have been around for only a few years less than Cat5E cables. However, they have primarily been used as the backbone to networks, instead of being run to workstations themselves. The reason for this beyond cost is the fact that, while cat6 cable can handle up to 10 Gigabits of data, that bandwidth is limited to 164 feet — anything beyond that will rapidly decay to only 1 Gigabit (the same as Cat5E)

Exercise 2:

Examine the network in your college computer lab. State the type of network and physical topology used. Examine all network media and connectors in the lab. Write a brief report that gives the following detail:

a.    State the network type and physical topology

·         Local Area Network

·         Star Topology

b.    Describe each connection (e.g. computers to face plate – do not repeat each computer connected in this way) in the network including:

Device at each end of the connection

·         27 Computers

·         1 Printer

·         2 Switch

·         1 Router

Cable used (or wireless)

·         Cat 5

Connector used at each end.

·         Rj45

c.    Describes connection to any external network. For example, connection to the telecommunications closet and vertical cabling and/or connection to the internet.

·         The 27 computers inside Laboratory 6 is connected to 2 switches. It is using a star topology network.

·         The 2 switches is connected to a router

·         The router is connected to main switch

·         The main switch is connected to the server

d.    If possible, get your teacher or network administrator to show you the data transfer rates on the network and include these in your report.

PING - It measures the round-trip time for messages sent from the originating host to a destination computer that are echoed back to the source.

·         29 m/s - the lower the ping, the better

DOWNLOAD SPEED – 0.16Mbps - receiving data is slow

UPLOAD SPEED – 14.32Mbps  - sending data is fast

Reference

·         https://www.lifehacker.com.au/2013/04/ask-lh-whats-the-difference-between-cat5-cat5e-and-cat6-cables/

·         Christopher, J. (2017). Cat5 vs Cat6 Cables: What are the Differences? – FireFold Blog. [online] Firefold.com. Available at: https://www.firefold.com/blog/difference-between-cat5-vs-cat6-cables/ [Accessed 22 May 2017].

·         http://beta.speedtest.net/result/6315723373esult/6315723373

COMPUTER NETWORK | TOPIC 3 | WIRELESS NETWORK

1.      Explain wireless network and Wi-Fi. Identify the advantages of wireless network.

Wireless networks - use radio waves to connect devices such as laptops to the internet, the business network and applications. When laptops are connected to Wi-Fi hot spots in public places, the connection is established to that business’s wireless network.

           

            ADVANTAGES OF WIRELESS NETWORKS

·         Users can move around freely within the area of the network with their hand held devices.

·         Users are able to share files and other resources with other devices that are connected to the network without having to be cabled to port.

·         Not having to lay lots of cables and put them through walls etc can be considerable advantage in terms of time and expense. It also makes it easier to add extra devices to the network, as no new cabling is needed.

·         Having a wireless network in a business can attract more customers  as they love wireless networks because of convenience.

·         Instant transfer of information to social media is made much easier.

Wi-Fi – a facility allowing computers, smartphones, or other devices to connect to the Internet to communicate with one another wirelessly within a particular area.

2.      List all of the wireless devices in your home and college. Briefly explain the purpose of each device.

·         Laptop – typing or watching can be done anywhere around the house

·         Mobile phones – Communication is easier as compared to landlines, more people are able to contact different people at the same time.

·         Printer – It can be accessed through Wi-Fi so we do not have bring the file that we need to print close to the printer.

·         Router – It is used to connect different devices to the internet at the same time.

·         IPad – Similar to the use of laptop but much more portable.

3.      Research the IEEE 802.11g and 802.11n standards. Explain the key points of each standard including the data rates & make comparison between the two standards.

	802.11g	802.11n
Explanation	Is backward compatible with wireless B devices. Odds are that you do not have a device that only supports Wireless B, but if you do then this is a benefit. As you can see, the man benefit of a Wireless G router over a Wireless B router is speed.	Wireless networking standard created to improve network throughput (maximum speed and transmission capabilities) over the two prior standards      Uses technologies including OFDM and MIMO to enable it to provide high speed data transfer at 600Mbps peak
Transfer rate	54mbps	600-900 mbps
Frequency	2.4GHz	2.4GHz / 5GHz
Wireless Channel Width	20MHz	40MHz
Usage	·    Only few computers at home ·    Usage is for checking E-mail and reading news or blogs	·    Several Computers at home using high-bandwidth sites like YouTube at the same time ·    Downloading a lot of large files ·    When online gaming
range	·    50 feet	·    175 feet

4.      Explain the different wireless network security risks and give the possible solution un order to avoid these risks.

·         DENIAL OF SERVICE – a valid user is denied the services offered by the network as the network resources are occupied by the attacker who continually bombards a targeted AP (Access Point) or network with bogus requests, premature successful connection messages, failure messages, and/or other commands.

Ø  DATA PROTECTION WHILE TRANSMISSION – This is done as mentioned before by encrypting the transmitted data. Even though being a challenge, it’s essential, by translating the data into a language which only intended user understands.

Ø  GRANTING ACCESS TO AUTHORIZED USERS – Give unique login IDs and passwords for authentication.

·         MAN-IN-THE-MIDDLE ATTACK – it is executed when a hacker logs into a computer which he uses to access the wireless card which can be used to sniff the network traffic.

Ø  WPA AND WPA2 – These standards are certified by the Wi-Fi Alliance providing enterprise solutions. It provides mutual authentication for verifying individual users.

·         MAC SPOOFING – here, the network cracker listens to the network traffic and is able to know the MAC address of that computer which has an access to the network, some software’s allow the cracker to pretend it has the desired MAC address and it can fool the network by granting access to it.

Ø  RF SHIELDING – Some schemes can be used to prevent wireless network signals from propagating outside the network premises. This can be very helpful against eavesdropping and it makes it difficult to receive the signals from the hackers.

·         JAMMING ATTACKS – This type of attacks can be executed in a Wi-Fi network to disrupt its communication. The attacker floods the Wi-Fi spectrum with powerful signals on the same frequency, which interferes with the communication between the AP and its users.

Ø  VPN – it can provide security to the users using mobile devices and want to access the network. The data tunnels through two or more points on a network using encryption so it is protected when being transmitted over unsecured networks such as the public internet

5.      Find at least FOUR (4) wireless networking protocols and explain each protocols

·         WAP – (Wireless Application Protocol) is a specification for a set of communication protocols to standardize the way that wireless devices can be used for Internet access.

·         NFC – (Near Field Communication) used for very close communication. When you wave your phone over a card reader to pay for groceries.

·         WEP – (Wired Equivalent Protocol) a security protocol specified in the IEEE Wi-Fi standard

·         WPA – (Wi-Fi Protected Access) the improvement of WEP and possibly to replace it.

·         Bluetooth – is a global 2.4 GHz personal area network for short-range wireless communication. Device-to-device file transfers, wireless speakers, and wireless headsets are often enabled with Bluetooth

·         ZigBee – is a 2.4 GHz mesh LAN protocol.

·         Z-Wave – is a sub-GHz mesh network protocol, and is proprietary stack. It is often used for security systems, home automation and lighting controls.

REFERENCE

·         https://www.techopedia.com/definition/26186/wireless-network

·         https://turbofuture.com/computers/Wireless-Network-vs-Wired-Network-Advantages-and-Disadvantages

·         https://www.flashrouters.com/blog/2012/11/29/the-difference-between-wireless-g-wireless-n-wireless-ac/

·         http://homenetworkadmin.com/wireless-b-vs-g-vs-n-vs-ac-difference/

·         http://www.everymac.com/systems/apple/apple-tv/apple-tv-faq/what-is-802.11n-differences-between-802.11n-802.11a-802.11b-802.11g.html

·         http://searchnetworking.techtarget.com/tutorial/Wireless-protocols-learning-guide

·         https://www.link-labs.com/blog/complete-list-iot-network-protocols

·         https://www.ukessays.com/essays/computer-science/wireless-network-security-issues-challenges-and-solutions-computer-science-essay.php