Computer networks worksheet with answers

Free printable Computer networks worksheet: 8 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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Name: ____________________   Date: ____________

1.Easy

Which OSI layer transmits raw bits as electrical, optical or radio signals?

  1. APhysical layer
  2. BNetwork layer
  3. CData link layer
  4. DSession layer
2.Easy

Which device simply repeats every incoming signal out of all its other ports?

  1. AA switch
  2. BA hub
  3. CA router
  4. DA firewall
3.Easy

Which device forwards packets between different networks based on IP addresses?

  1. AA router
  2. BA switch
  3. CA repeater
  4. DA hub
4.Medium

Why is UDP often preferred for live video calls?

  1. AUDP guarantees every packet arrives, so the picture never freezes
  2. BUDP is required for all video
  3. CLow delay matters more than retransmitting every lost packet
  4. DUDP encrypts data automatically
5.Medium

What does a subnet mask of 255.255.255.0 correspond to in CIDR notation?

  1. A/24
  2. B/16
  3. C/32
  4. D/8
6.Medium

A signal travels 2000 km through fibre at about 2 × 10⁸ m/s. What is the propagation delay?

  1. A100 ms
  2. B0.1 ms
  3. C10 ms
  4. D1 ms
7.Hard

A server's private key is stolen a year from now. Which TLS property keeps today's recorded sessions safe?

  1. ASending the certificate twice
  2. BForward secrecy from ephemeral Diffie-Hellman key exchange
  3. CCompressing the data before encryption
  4. DUsing a longer domain name
8.Hard

Which mechanism prevents broadcast loops in a network with redundant switch links?

  1. ADHCP snooping
  2. BNAT
  3. CSpanning Tree Protocol
  4. DARP caching

Answer key

  1. 1. A · Physical layer
  2. 2. B · A hub
  3. 3. A · A router
  4. 4. C · Low delay matters more than retransmitting every lost packet
  5. 5. A · /24
  6. 6. C · 10 ms
  7. 7. B · Forward secrecy from ephemeral Diffie-Hellman key exchange
  8. 8. C · Spanning Tree Protocol

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