Go CCIE Go!! - A Cisco Certified Internetwork Expert

The first reason typically given is scalability. This is due to the fact that with VLANs we can break the network up into smaller, more manageable broadcast domains (TCP/IP subnets).
When you replace your hubs with switches and setup your workstations for Full Duplex operation, your network has just become incredibly more efficient. This is due to eliminated collisions as each system is now intelligently having its traffic forwarded to the correct unicast recipient.
The problem that still remains, however, is broadcast traffic. The more switches you add, and the more clients that join the single VLAN, the more broadcast traffic becomes an issue. VLANs allow us to carve the single broadcast domain into multiple broadcast domains. This gives us a scalability solution for broadcast traffic as well as unicast.
I hope this helps you…for more generic information on the wonders of VLANs - check out -
http://en.wikipedia.org/wiki/VLAN
Warmest regards,
Anthony J. Sequeira, CCIE #15626, CCSI #23251 Senior CCIE Instructor
asequeira@internetworkexpert.com
Internetwork Expert, Inc. http://www.InternetworkExpert.com Toll Free: 877-224-8987 Outside US: 775-826-4344

On 10/15/08 6:49 PM, “nouman abbasi” wrote:
> Hi, > > Why do u use VLANS ?? > > Most common answer is Security / Broadcast Domain ?? > can some add more to it… > > > > Thanks > > > Blogs and organic groups at http://www.ccie.net > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html
Blogs and organic groups at http://www.ccie.net