OCR GCSE Computer Science (J277) · Computer systems (Paper 1) › Networks, connections and protocols › Wired and wireless networks, protocols and layers
Practise The concept of layers. 11 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
Written for this site in the style of OCR exam questions. They are not taken from real past papers.
Question 1Easy3 marks
(a) State what is meant by a layer in a network model.[1]
(b) State one benefit of dividing network communication into layers.[1]
(c) Which one of these statements about network layers is true? Tick (✓) one box.[1]
Each layer only communicates with the layers directly above and below it
Every layer carries out every job
Layers are only used on wireless networks
All of the layers must be made by the same company
Show the answer and mark scheme
(a)
a division of the network's protocols / functions, where each layer has a specific job
(b)
a change to one layer does not affect the others / developers can focus on one layer / hardware and software from different manufacturers can work together / problems are easier to find
(c)Answer: Each layer only communicates with the layers directly above and below it
Question 2Medium4 marks
Explain two benefits of dividing network protocols into layers.[4]
Show the answer and mark scheme
each layer is self-contained
so a change / improvement to one layer does not affect the other layers
developers can concentrate on one layer / area of the network
without needing to know how every other layer works
hardware and software from different manufacturers can work together
as long as each follows the standards / protocols for its layer
it is easier to find and fix problems
because each layer has a clearly defined job
Question 3Hard4 marks
A company designs a new, faster type of network cable.
(a) Explain how layering means that email software and web browsers do not need to be rewritten to use the new cable.[3]
(b) State one other benefit of layers for the company that makes the cable.[1]
Show the answer and mark scheme
(a)
the cable belongs to the lowest (link) layer
email software and browsers work at the highest (application) layer
layers are independent and communicate through standard interfaces / protocols
so as long as the new cable follows the rules for its layer, the layers above are not affected
(b)
it only has to design hardware for one layer / its cable will work with other manufacturers' equipment that follows the same standards