Re: VLANs confusing

[Aaron Howell <aaron_howell () ngenuity-is com>]

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Raj Shaz wrote:
> Hi group

Howdy

> All i understand of VLANs is encryption of packets at source and
> decryption at destination. Now If at both ends i have cisco
> devices,which protocols/ algorithms are used by them?. I have notices
> configuration of DAX switches on cisco network the VLANS doesnot work.
> Which protocol does these machines should used then?

Are you sure you mean to ask about VLANs? A VLAN in and of itself has
absolutely nothing to do with encryption/decryption of traffic flowing
across it. In a wireless environment, this is not necessarily the case,
but you did not specify wired or wireless, so I'm not clear...

> When two cisco devices are configured for VLANs , we basically make
> these devices to transfer key (for en/decryption) ,does these keys has
> any relevance with other VLANs?. Is there exists a possibility of key
> overlapping on gigantic network ( akin internet ).

See above...

> Which layer VLANS works, layer 3 right?. Then what do u mean when u
> say VLAN enabled layer 2 switches?

All switches are layer 2 devices. Some switches have additional
functionality that makes them capable of operating in layer 3, also.
VLANs actually work at layer 2. The easiest way I can think of to
explain it is this:

Using a VLAN is like splitting your switch into 2 (or more) switches.
Broadcast traffic for one VLAN will not (in most cases) be forwarded
into the other VLANs on that switch.

> Sorry, seems rudimentary stuff. But hope my brain is highlighted with
> some wisdom.Some ref to good notes online?

Here are a couple of links I found that have relevant info. Hope this helps.

http://computer.howstuffworks.com/lan-switch15.htm
http://computer.howstuffworks.com/lan-switch16.htm

Aaron


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