Computer Networks
Table of Contents
Network: overview
The layer answers:
- how to get from A to B
- how to prevent network congestion
- how to provide quality of service
- how to connect multiple networks together
layers below it don’t know about end-to-end delivery layers above it don’t know about the network topology nobody knows anything about routing — it’s the network layer’s job
Service types — connectionless v.s. connection-oriented
| Connectionless | Connection-oriented |
| - routers use algorithms for routing to send each packet individually - used by IP  | - fixed route decided when a connection is made - all packets go along that route - sometimes used by ISPs on top of IP  |