Network Links

• The combination of signal and channel^[signals are transmitted via channels] form a Link.
• A link directly connects to one or more hosts Networks consists of multiple interconnected links(devices connecting links are routers or switches)

Network Switching

Circuit Switched Network

a dedicated circuit setup for A and B to communicate A and B exchange arbitrary length messages guaranteed capacity once circuit is created. created circuits will Block other circuits (e.g. the C to D path)

Packet Switched Network

messages are divided into small packets before being sent. Allows multiple pairs paths to share the same link simultaneously. connectivity is guaranteed capacity varies on network usage packets are small and has size limits a message can be made up of many packets