2. Connectivity methods

3. Exam Answer
WAN/LAN
 Each office will have its own Local Area Network or LAN.
 But the company also wants to link those offices to create a Wide Area Network or WAN.
 That will enable staff across the company to work together more efficiently, such as by sharing data more easily between offices
 Each LAN also needs to connect using the largest WAN of them all – the Internet.
ADSL - Broadband
This is the connection method used by most homes and many businesses, which uses traditional copper phone lines (Fibre Backbone). Asymmetric is because the frequency is split up, with more allocated to the downstream than the upstream.
Advantages
 ADSL gives a broadband connection with good data transfer speeds (or ‘high bandwidth’).
 ADSL is easy to install with familiar hardware devices such as a router (with built-in modem) plus micro-filters that split voice and data to send via the phone line.
Disadvantages
 ADSL uses the shared public telephone system so is weak on security unless the organisation also uses a Virtual Private Network or VPN, which would use encryption to scramble data being sent over the WAN.

4. ADSL - Broadband Exam Answer
A VPN Site to site - You have two offices and you want to be able to access shared files, internal web sites, etc from both locations.  A VPN allows you to securely do that, which is also known as creating a WAN (Wide Area Network)
Office
Office

5. Exam Answer
Leased Line
Is a popular choice for businesses that want a dedicated connection between their sites, such as between the different offices of a business across the country.
Advantages
 Having a dedicated line means you do not share it with any other users (which is also known as ‘uncontended’)
 That means you are guaranteed a very high bandwidth, which will give fast data transfer for your business
 It also means your data is more secure, which will keep data private for the business
Internet Leased Lines offer same speed for both uploads and downloads (symmetric connectivity)
 Leased lines also normally use fibre optic cable, which also gives much faster data transfer than copper cable
Disadvantages
 Leased lines are more expensive to buy as a package from a telecoms company or ISP (internet service provider).
 A leased line will also take more time to set-up and install because it involves fibre links
Justification of best option
Which one?

6. Leased Line Exam Answer Office Office
A CSU/DSU (Channel Service Unit/Data Service Unit) is a digital-interface device used to connect a data terminal equipment (DTE), such as a router, to a digital circuit, such as a Digital Signal 1 (T1) line. The CSU/DSU implements two different functions.

7. Extra Information

8. Telephone Exchanges – all over the country
Wi-Fi signals
Wi-Fi Router/Modem – connects to the internet via twisted pair or fibre optic cable under the ground, then distributes data to devices
Phone Mast generating 3G and 4G signals (microwaves) – these are all over the country
Telephone Exchanges – all over the country
Telephone Junction Box
Underground Cable
Cable Ties technician can receive data on their smartphone through the client’s house Wi-Fi or via 3G. Will use infrared to communicate with the TV
Receive call or data from technician/CTL then forwarded onto the exchange
Telephone Junction Box
CTL
Wi-Fi & Wired LAN
Underground Cable
Phone Mast generating 3G and 4G signals (microwaves) – these are all over the country
Cable Ties Ltd – has Wi-Fi and a WIRED LAN connected to a Modem/Router to connect to the internet via twisted pair or fibre optic cable under the ground

9. 3.4 – Network Characteristics - Lines
There are 2 ways in which a company or individual can connect to the internet, each comes with a cost and benefits. These are an ADSL or a Leased Line
Leased line
Refers to a phone ISDN line that is rented for exclusive, 24 hours a day, 7 days a week use. A leased line connects two locations for private voice and/or data telecommunication service. Leased lines can span short or long distances. They maintain a single open circuit at all times, as opposed to traditional telephone services that reuse the same lines for many different conversations through a process called "switching."
Internet Leased Lines offer same speed for both uploads and downloads (symmetric connectivity
Leased lines most commonly are rented by businesses to connect branch offices, because these lines guarantee bandwidth for network traffic.

10. 3.4 – Network Characteristics - Lines
ADSL - Broadband
Short for asymmetric digital subscriber line, ADSL is a type of DSL broadband communications technology used for connecting to the Internet. ADSL allows more data to be sent over existing copper telephone lines, when compared to traditional modem lines. This is the connection method used by most homes and many businesses. The reason ADSL is asymmetric is because the frequencies available were split up, with more allocated to the downstream than the upstream.
ADSL vs. Leased Line
While there are business broadband options available at pretty good price points, Internet Leased Lines are still preferred with a lot of customers for the following reasons:
Internet Leased Lines offer same speed for both uploads and downloads (symmetric connectivity), while in broadband (through DSL technology) the speeds are always optimized for downloads and the upload speeds are much lesser.
Higher bandwidth (Greater than 8 Mbps) is possible only through Internet Leased Lines.
Internet Leased Lines come with unlimited usage plans which enables companies to add services like video, voice etc.