CCNA

WHAT

I'm trying to study to get my CCNA degree :D I'm using my wiki to note what I'm trying to learn ! Much of the stuff here are from SYBEX CCNA Study guide (6th edition). Hope it'll help other people.

Software

I'm using GNS3 to emulate a Cisco environment. Get it from GNS3 Homepage

Switches

Graphicaly represented by

They work at Layer 2

They break up "collision domains" only.

Routers (Layer 3 switches)

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They work at Layer 3

Cisco calls them multiport bridges.

Advantages:

• They break up "broadcast domains" by default ( 1 broadcast domain per interface ).

• They break up "collision domains".

• Can filter network based on Layer 3 ( Network Layer ) information ( e.g., IP Address )

Useful at:

• Packet switching

• Packet filtering

• Internetwork communication

• Path selection

Bridges

Graphicaly represented by

They break up collision domains.

Hubs

Graphicaly represented by

They keep all hosts in the same collision domain.

They often cause traffic congestion if on a busy network.

Traffic Congestion

Can be caused by:

• Too many hosts in a broadcast domain

• Broadcast storms

• Multicasting