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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1.Easy

In the client-server model:

  1. AServers send requests and clients answer them
  2. BClients send requests and a server provides the service
  3. CEvery computer stores the whole internet
  4. DAll devices must be in the same room
2.Easy

Which IPv4 address is the standard loopback address of a host?

  1. A192.168.0.1
  2. B127.0.0.1
  3. C0.0.0.0
  4. D255.255.255.255
3.Easy

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

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

Why is UDP often preferred for live video calls?

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

How many usable host addresses does a /26 IPv4 subnet have?

  1. A64
  2. B62
  3. C126
  4. D30
6.Medium

Which subnet mask corresponds to /20?

  1. A255.255.248.0
  2. B255.255.224.0
  3. C255.255.255.240
  4. D255.255.240.0
7.Hard

With sliding-window protocols, how does Go-Back-N differ from Selective Repeat after one frame is lost?

  1. AGo-Back-N resends the lost frame and all later ones; Selective Repeat only the lost one
  2. BGo-Back-N resends only the lost frame; Selective Repeat resends that frame and all later ones
  3. CBoth resend the whole window from the start
  4. DNeither ever resends lost frames
8.Hard

Why does the side that closes a TCP connection first stay in the TIME_WAIT state for twice the maximum segment lifetime?

  1. ATo let the routers along the path update their routing tables for the next connection
  2. BTo wait for the DNS cache to expire
  3. CTo keep the encryption keys for later reuse
  4. DSo delayed segments die out and the final ACK can be resent if it was lost

Answer key

  1. 1. B · Clients send requests and a server provides the service
  2. 2. B · 127.0.0.1
  3. 3. D · A hub
  4. 4. A · Low delay matters more than retransmitting every lost packet
  5. 5. B · 62
  6. 6. D · 255.255.240.0
  7. 7. A · Go-Back-N resends the lost frame and all later ones; Selective Repeat only the lost one
  8. 8. D · So delayed segments die out and the final ACK can be resent if it was lost

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