Hi,
Why VLAN's, well yes you can infact run multiple subnets on a flat network but each
broadcast will be seen by every port as there is no restriction on what ports are
sending them out. The switch ports are layer 2 therefore they don't understand
255.255.255.255 and see it as something to let through.
When using VLAN's however we are defining stuff in the switch at a layer 2 level which
says this group of ports (group red) all belong together this other set of ports
belong together and can not see data from the next group (group blue). The only way to
get the data across is via a router. By default routers do not allow broadcasts
across the networks so now we have separation.
Basically as I understand it a port recieves the data and say is this data belonging
to the VLAN I'm in if yes then let it leave if not then block it.
Hope this helps
Teunis,
Hobart, Tasmania
Australia
On Sunday, January 14, 2001 at 11:46:10 PM, ahmad bilal wrote:
> hi ,
>
> actually i have a question ,why are vlan used and what are its advantages
> cause this has me confused.
> if we make vlans what is the technical advantage ,if its limiting broadcasts
> then subneting and using switch makes it possible,if it is security how is
> it secure as vlans still are able to comunicate via routers or in case of
> layer 3 switch.
> is it true that vlans have advantage only in lan's or using layer 2 no ip
> addreses associated with vlans.
>
>
> ""Jeff Duchin"" <[EMAIL PROTECTED]> wrote in message
> 93sp4p$cce$[EMAIL PROTECTED]">news:93sp4p$cce$[EMAIL PROTECTED]...
> > Is it me, or is it that LAN switching engineers here are rare? Is anyone,
> > beside myself, using dynamic VLANs in a multi-layer campus environment?
> >
> > Jeff
> >
> >
> > _________________________________
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