CCNA: Difference between revisions

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==Switches==
==Switches==
 
[[Image: Switch_representation.png|60px|thumb]]
Graphicaly represented by [[Image: Switch_representation.png|60px|thumb]]


They work at Layer 2
They work at Layer 2
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==Routers (Layer 3 switches)==
==Routers (Layer 3 switches)==
 
[[Image: Router_representation.png|60px|thumb]]
Graphicaly represented by [[Image: Router_representation.png|80px]]


They work at Layer 3
They work at Layer 3
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==Bridges==
==Bridges==


Graphicaly represented by [[Image: Bridge_representation.png]]
Graphicaly represented by [[Image: Bridge_representation.png|60px|thumb]]


They break up collision domains.
They break up collision domains.
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==Hubs==
==Hubs==


Graphicaly represented by [[Image: Hub_representation.png]]
Graphicaly represented by [[Image: Hub_representation.png|60px|thumb]]


They keep all hosts in the same collision domain.
They keep all hosts in the same collision domain.

Revision as of 17:54, 26 March 2010

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

Error creating thumbnail: File missing

They break up collision domains.

Hubs

Graphicaly represented by

Error creating thumbnail: File missing

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