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 URL https://www.example.com/index.html, which part is the host name?

  1. Ahttps
  2. Bexample.com/index.html
  3. Cindex.html
  4. Dwww.example.com
2.Easy

What is encapsulation in layered networking?

  1. AEach layer removes the header added by the layer above before sending
  2. BCompressing packets to save bandwidth
  3. CEach layer adds its own header to the data from the layer above
  4. DEncrypting all data before sending it
3.Easy

What does a VPN mainly provide?

  1. AA free public IP address for every device
  2. BAutomatic backup of files to a server
  3. CA faster physical connection to the internet through a dedicated line
  4. DAn encrypted tunnel across an untrusted network such as the internet
4.Medium

Why is UDP often preferred for live video calls?

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

Why does a switch sometimes send a frame out of all ports except the one it came in on?

  1. AThe frame is too large for one port
  2. BThe destination MAC address is not yet in its address table
  3. CThe switch is acting as a router
  4. DThe frame has a wrong IP checksum and must be checked by every host
6.Medium

NAT (network address translation) is mainly used to:

  1. AEncrypt traffic between two sites
  2. BLet many devices with private addresses share one public IP address
  3. CTranslate domain names into IP addresses for devices on a local network
  4. DIncrease the speed of a network cable
7.Hard

Stations A and C both reach access point B but cannot hear each other, so their frames collide at B. How does 802.11 help?

  1. ABy routing A's frames through C
  2. BOptional RTS/CTS exchanges: the AP's CTS tells all nearby stations to wait
  3. CBy increasing the TTL of the frames
  4. DBy making A and C use collision detection so they stop sending when frames overlap
8.Hard

Why does a browser warn when a site presents a self-signed certificate?

  1. ASelf-signed certificates use no encryption at all, so the traffic is sent in clear text
  2. BNo trusted certificate authority vouches that the key belongs to that site
  3. CThe site must be using HTTP instead of HTTPS
  4. DThe certificate is always expired

Answer key

  1. 1. D · www.example.com
  2. 2. C · Each layer adds its own header to the data from the layer above
  3. 3. D · An encrypted tunnel across an untrusted network such as the internet
  4. 4. D · Low delay matters more than retransmitting every lost packet
  5. 5. B · The destination MAC address is not yet in its address table
  6. 6. B · Let many devices with private addresses share one public IP address
  7. 7. B · Optional RTS/CTS exchanges: the AP's CTS tells all nearby stations to wait
  8. 8. B · No trusted certificate authority vouches that the key belongs to that site

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