How do real communication systems such as email, messaging, the internet and EDI carry out the information processes?
Describe examples of communication systems, including email, instant messaging, the internet and the web, electronic data interchange and teleconferencing, and how each transmits and receives information
A focused answer to the HSC Information Processes and Technology dot point on examples of communication systems. Email, messaging, the internet and web, EDI and teleconferencing, with the client server model and the traps markers look for.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this dot point is asking
NESA wants you to describe real, named communication systems and explain how each carries out transmitting and receiving. You should be able to outline how the system works, name the protocols or technologies it uses, and identify whether it follows the client server or peer to peer model. This grounds the abstract framework and protocol theory in everyday systems.
The answer
The client server model
Many communication systems use the client server model: a client (a browser, mail program or app) sends a request, and a server (a powerful, always-on computer) processes it and returns a response. The server centralises data and services; clients are lightweight and numerous. Some systems instead use peer to peer, where each device acts as both client and server, sharing directly without a central server.
Email is a store and forward system. The sender's client passes the message to a mail server using SMTP (Simple Mail Transfer Protocol), which relays it server to server until it reaches the recipient's mail server, where it is stored. The recipient later retrieves it using POP (which downloads) or IMAP (which keeps it on the server and syncs). Email is asynchronous: the recipient need not be online when it is sent.
Instant messaging and teleconferencing
Instant messaging carries short text messages in near real time, showing presence (who is online) and delivery status. Teleconferencing extends this to voice and video, letting people in different locations meet. These systems are synchronous, needing both ends active, and they place tight demands on bandwidth and latency, especially for video, where delay and jitter degrade the experience.
The internet and the web
The internet is a worldwide network of interconnected networks, all communicating through the TCP/IP protocol suite, which handles addressing, routing and reliable delivery of packets between any two connected devices. The web is one service running over the internet: web servers store hypertext documents and resources, and browsers request them using HTTP (or secure HTTPS), following hyperlinks identified by URLs. The internet is the infrastructure; the web is an application of it, and email and messaging are other applications.
Electronic data interchange
Electronic data interchange (EDI) is the automatic exchange of structured business documents, such as purchase orders and invoices, directly between the computer systems of trading partners in an agreed standard format. Because the documents are structured and machine readable, no re-keying is needed: one company's order becomes another's sales record automatically, reducing errors, delay and cost. EDI is a backbone of supply chains.
Mapping to the information processes
In every example, transmitting and receiving moves the data; collecting captures the message or document; storing and retrieving holds it (a mail server, a message history); and displaying presents it to the user. Comparing examples by how they carry out these processes, and whether they are synchronous or asynchronous, is exactly the analysis NESA rewards.
Exam-style practice questions
Practice questions written in the style of NESA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
2021 HSC4 marksA bank is introducing a new system to allow its staff to work from home and its customers to have greater access to online banking features. Describe how internet, intranet and extranet technologies can be used in this system.Show worked answer →
For 4 marks define each technology and apply it to the bank.
Internet. The public global network. Customers connect over the internet to reach the bank's online banking website from anywhere, and staff use it as the carrier (often through a VPN) to reach the bank's systems from home.
Intranet. A private network owned by the bank, accessible only to authorised staff. Employees working from home log in to the intranet to access internal resources such as policies, internal tools and staff records.
Extranet. A controlled extension of the intranet that lets specific external parties in. The bank could give partners or business customers secure access to selected services and shared data through an extranet.
Markers reward a correct definition plus a relevant application of each of the three technologies to the work-from-home and online banking scenario.
2020 HSC1 marksWhich communication system provides a means of sharing and collaboration by allowing a group of people to enter, modify and contribute one or more pages of related text? A. Wiki. B. Email. C. Podcast. D. RSS feed.Show worked answer →
The answer is A, Wiki.
A wiki is a collaborative website where a group of users can collectively create, edit and link pages of related text directly in the browser. Multiple contributors can enter and modify the same pages, which is exactly the sharing-and-collaboration function described.
Email sends messages between individuals, a podcast is published audio for listeners to download, and an RSS feed pushes update notifications to subscribers - none allows a group to jointly edit shared pages. The collaborative editing system is the wiki.
2020 HSC1 marksAn email is sent From: Chris, To: Bob, CC: Dan, BCC: Ash. Which of the following statements is correct? A. Bob and Dan are aware that Ash received the email. B. Dan is aware that Ash and Bob received the email. C. Ash is aware that Bob and Dan received the email. D. All recipients are aware that the others received the email.Show worked answer →
The answer is C, "Ash is aware that Bob and Dan received the email."
The To and CC fields are visible to every recipient, but the BCC (blind carbon copy) field is hidden from everyone except the sender. So:
Bob (To) and Dan (CC) can see each other but cannot see that Ash was BCC'd.
Ash (BCC) can see the sender and the visible To and CC recipients, so Ash knows Bob and Dan received it.
Therefore the only correct statement is that Ash is aware Bob and Dan received the email, while they are unaware of Ash. The answer is C.