#4 Jun 2022 Q3(b) 7 marks 1.3.2 IPv4 address structure (cloze)

Question

Lead-in (Q3 stem): A library has a LAN (Local Area Network).

(b) Users can access websites from the library computers. Complete the description of accessing websites using the given list of terms. Not all terms will be used.

0 1 127 128 255 256 Colon Domain Name Server Embedded systems File server Full stop Hyphen Internet protocol MAC address Router Uniform Resource Locator Web server Clients

A website is hosted on a 1 . The computers that access the websites are called 2 .

The user enters the 3  into a web browser. The web browser sends a request to the 4  for the matching IP (Internet Protocol) address. If found the IP address is returned. A request is then sent to this IP address.

An IPv4 address is made of 4 groups of digits. Each group can be between the denary values 5  and 6 . The groups of digits are separated by a 7 .

[7]

Why this question is tricky

Few candidates were able to accurately identify the denary values that can be used in an IPv4 address. 256 was a common error for the highest number, and 1 was also often given as the lowest number. The answer for the final space was often given as a colon or a hyphen. Few candidates were able to accurately identify the full stop as being the separator.— J277_01_ER_Jun2022.txt lines 209-212

MS complexity 9/10: Strict wordlist matching across 7 gaps. "Do not allow 'server' for web server" — the wordlist also contains "File server" as a distractor.

Full-marks model answer

A website is hosted on a Web server. The computers that access the websites are called Clients.

The user enters the Uniform Resource Locator into a web browser. The web browser sends a request to the Domain Name Server for the matching IP (Internet Protocol) address.

An IPv4 address is made of 4 groups of digits. Each group can be between the denary values 0 and 255. The groups of digits are separated by a Full stop.

Mark allocation (7 marks — 1 per gap)
  • Web server — must be the full term; "server" alone is not accepted (File server is also in the list).
  • Clients — given in the wordlist.
  • Uniform Resource Locator — full term required, not "URL".
  • Domain Name Server — BOD "domain name system".
  • 0 and 255 — accept in either order (one mark each).
  • Full stop — not "colon" (IPv6) or "hyphen" (MAC address).

Watch out for...

Memorise: IPv4 octets are 0 to 255 inclusive (not 1 to 256 — the range is 256 values but the highest value is 255, like 0–9 being 10 digits). The separator is a full stop — colons belong to IPv6, hyphens to MAC addresses. Don't shorten "Web server" to "server".