Week 2 Flashcards
What is routing?
Determine end-to-end path through the network
What is forwarding?
Forwarding table determines local forwarding at this router
What is a routing algorithm?
Determine a “good” path through a network from source to destination
What are “link state” algorithms?
All routers have a complete topology and link cost information (GLOBAL)
What are “distance vector” algorithms?
A router only knows physically-connected neighbours and links cost to them
Iterative process of computation, exchange information with neighbours
What are the pros of using a distance vector algorithm?
Great for fast changing networks
What are the cons of using distance vector?
Doesn’t scale well as it relies on local knowledge
Suffers from problems like count-to-infinity and persistent looping
What are pros of using Djikstra?
Efficient and can handle large graphs
What are cons of using Djikstra?
Message size grows with the network
What is the count-to-infinity problem?
When a link between two routers fail, and they continue to update their routing tables with incorrect information the costs will increase indefinitely.
What is the persistent looping problem?
Packets are routed in an endless circle between routers due to incorrect routing information
What is the poisoned reverse?
It prevents routing loops by setting one of the costs to infinity.
What does internet consist of?
Applications, Computing Devices, Networking Devices, Protocols
