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

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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

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They break up collision domains.

Hubs

Graphicaly represented by

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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