5_6Chapter Routing Concept _ Routing Protocols

• Router


  Device that receives packets from a source and delivers them to the destination
• Requirements of the routing function

  • Correctness
  • Simplicity
  • Robustness
  • Stability
  • Fairness
  • Optimality
  • Efficiency
• Routed protocol


  Protocol that contains sufficient network-layer addressing information for user traffic to be directed from one network to another network
• Routing protocol


  Provides mechanisms for sharing routing information between routers
• Types of routing


  • Static routing
  • Default routing
  • Dynamic routing
• Routing algorithms


  • Non-Adaptive or Static
  • Adaptive or Dynamic
• Convergence


  Consistency and accuracy of information about the network topology across all routers
• Metrics used to represent distance


  • Hop count
  • Cost
  • Bandwidth
  • Delay
  • Load
• Distance vector routing


  Routing algorithm where each router maintains a table indicating the best known distance to each destination and which line/port to use to reach there
• Link state routing


  Routing algorithm where each router maintains a complex database of topology information and calculates the shortest path to every other router
• Comparison of distance vector and link state routing

  • Network topology view
  • Metric calculation
  • Convergence speed
  • Update mechanism
• Routing types


  • Interior routing
  • Exterior routing