Network Core
- A mesh of interconnected routers.
- packet-switching: hosts break application-layer messages into packets
- network forwards packets from one router to the next, across links on path from source to destination
- A packet from your computer to a server might cross many many routers (and links)
Two key network core functions:
Ex: When a packet arrives at a router, the router looks at its destination IP address, checks its forwarding table, and sends the packet to the next router or destination node based on the forwarding decision.
Summary
Basically, routing is the algorithm to find the best path for packets, and forwarding is the action of moving the packets between the interfaces based on the routing table which is built by the routing process.