Broadcast Domains and Collision Domains

Question 1

Collision domains

Answer 1

• A historical footnote
  
  • It’s difficult to find a collision these days
  • The word “collision” is misleading
• The network was one big segment
  
  • Everyone heard everyone else’s signals
  • One big conference call
• Only one station can “talk” at a time
  
  • Is the line clear? Ok, I can talk.
  • Carrier Sense Multiple Access (CSMA)

• When two people spoke at the same time, there was
a collision
• Collision Detection (CD) - Send the jam signal

Question 2

Broadcast Domains

Answer 2

• Spread the word!
  
  • Everyone must know!
  • ARP probes, operating system notifications
• How far can a broadcast go?
  
  • Passed by a switch/bridge
  • Stops at the router
• This can be important
• More devices, more broadcasts

Question 3

Unicast

Answer 3

• One station sending information to another station
• Send information between two systems
• Web surfing, file transfers
• Does not scale optimally for streaming media

Question 4

Broadcast

Answer 4

• Send information to everyone at once
• One packet, received by everyone
• Limited scope - the broadcast domain
• Routing updates, ARP requests
• Not used in IPv6 - focus on multicast

Question 5

Multicast

Answer 5

• Delivery of information to interested systems
  
  • One to many

• Multimedia delivery, stock exchanges

• Very specialized
  
  • Difficult to scale across large networks