Notes - Ch1 Computer Networks and the Internet

Ch1 Computer Networks and the Internet

Created: 2025-11-29

Updated: 2025-11-29

1.1 What Is the Internet

the internet := a computer network that interconnects billions of computing devices
hosts / end system := all of computing devices
communication links := connecting end systems with physical media
- including coaxial cable, copper wire, optical fiber, radio spectrum...
packets := segmented data with added header to be transfered
packet switches := guide packet from incoming communication links to outgoing one
- link-layer switches: used in access networks
- routers: used in the network core
route / path := the sequence of communication links and packet switches traversed by a packet from the sending end system to receiving one
RCFs (requests for comments) := stardard document of protocol
protocols := the format, order of messages sent and received among network entities, and actions taken on message transmission and/or receipt of a message or other event.

access networks := the network that physically connects an end system to the first router(aka edge router)
1. DSL (digital subscriber line)