Lecture 1

• Email: mandel@cse.yorku.ca
  
  • Email protocol
    
    • From your York computer science student account
      
    • Subject line 3213...
      
    • Identify yourself in the email by name and student number
      
  • Office hours
    
    • CSE3012
      
      • Tuesday and Thursday 11:30 – 1pm
        
  • Phone
    
    • 416 736 2100 x40630
      
  • Course webpage
    
    • http://www.cse.yorku.ca/course/3213
      
  • Grade Weighting
    
    • Subject to change
      
    • 15% - Assignments & Quizzes
      
    • 25% - MIDTERM
      
    • 60% - FINAL EXAM
      

 

Lecture 1

• What is a communication network?
  
  • The equipment (software and hardware) and facilities that provide the basic communication service
    
  • Virtually invisible to the user, usually represented by a cloud
    
    • Equipment
      
      • Routers, servers, switches
        
    • Facilities
      
      • Copper wire, coaxial cables, optical fibre
        
      • Telephone poles, ducts, conduits
        
• Network architecture
  
  • The plan that specifies how the network is built and operated
    
  • Architecture is driven by the network services
    
  • Communication process is complex
    
  • Network architecture partitions overall communication process into separate layers
    
    • Layers are to be built from the ground up on well designed low level layers reaching up to the top which is the application level
      
• Telegraph networks
  
  • Courier
    
    • Pony express, FedEX
      
  • Telegraph
    
    • Message is transmitted across a network using signals
      
      • From drums, beacons, mirrors
        
      • To electricity, light
        
      • Telegraph is quicker than courier
        
• Message Switching
  
  • Network nodes were created where several optical telegraph lines met
    
  • Store-and-forward operation
    
    • Messages arriving on each line were decoded
      
    • Next-hop in route determined by destination address of a message
      
• Electric Telegraph Networks
  
  • Message switching and store-and-Forward operation
    
  • Key elements
    
    • Addressing, routing, forwarding
      
  • Optical telegraph networks became obsolete
    
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