# Module Structure

## T1

- Networking Fundamentals
- Coursework 50%

## T2

- Focus on Security
- Exam 50%

# MAC (Medium Access Control) Protocol

- Physical to NIC
	- Checks if packet is for current NIC
	- Does packet contain error?

# LANs

## Hub

- Passive Device, sees incoming signals on one port and retransmits same signals on all other outputs.
- Half-Duplex
- Broadcast
- Doesn't need to understand what is transmitting

## Switch

- Where possible, retransmit signals to appropriate destination
- Must understand packet format and extract destination address
- Good switches can support multiple simultaneous conversations between disjoint pairs
- Modern switches can support full-duplex communication

## Repeater

- Joins 2 identical LANs to form a larger LAN
- Unintelligent, just retransmits
- Repeater creates a "collision domain"

## Bridge

- Forms a single Logical LAN from 2 Physical LANs
- Only retransmits packets on bridged LAN if necessary. (Reduces load, increases efficiency, allows parallelism)
- Will use MAC protocol of dest network to ensure full retransmission.

## Router / Gateway

- Interconnects two different LANs to form a WAN