1. Virtual Local Area Network
Bounds, Taylor
Fowler, Tucker
Pantoja, Erica
Sedys, Martynas
Kartawinata, Andrew

2. Content Definition How do VLANs work? LAN vs VLANs Advantages of VLAN
VLAN Limitations
Different types of VLANs

3. Definition
A Virtual LAN is logical subgroup within a local area network that is created via software rather than manually moving cables in the wiring closet.
A VLAN is an independent LAN network
A VLAN allows student and faculty PCs to be separated although they share the same infrastructure
A VLAN can be named for easier identification
Virtual LANs (VLANs) are an abstraction to permit a single physical network to emulate the functionality of multiple parallel physical networks. This is handy because there may be situations where you need the functionality of multiple parallel physical networks but you'd rather not spend the money on buying parallel hardware

4. Sounds kinda like subnetting…..
Nope

5. VLAN and Subnetting Subnetting
Hardware - mask applied at router to determine the network address
VLAN
Software - Ports on a network are grouped together into a VLAN to segregate traffic.
No masking needed
After VLAN is set up traffic between VLANs or between VLAN and larger network must be done with a router.

6. How do VLANs work?
Devices in different physical locations, not going back to the same router, can be on the same network
The limitation of subnetting a network with a router is that all devices on that subnet must be connected to the same switch and that switch must be connected to a port on the router

7. Advantages of VLANs Ease of administration
Confinement of broadcast domains
Reduce broadcast traffic
Enforcement of security policies
Increased performance
Switched networks by nature will increase performance over shared devices in use today by reducing collisions. Grouping users into logical networks will also increase performance by limiting broadcast traffic to users performing similar functions within workgroups. Additionally, less traffic will need to be routed, and the latency added to routers will be reduced.
Improved manageability
VLANs provide an easy, flexible, less costly way to modify logical groups in changing environments. VLANs make large networks more manageable by allowing centralized configuration of devices located in assorted locations.
Simplification of software configurations
VLANs will allow LAN administrators to "fine tune" their networks by grouping users. Software configurations can be made the same across machines with the consolidation of a department's resources into a single subnet. IP addresses and subnet masks will be more consistent across the entire VLAN. These services can be more effectively deployed when they can span buildings within a VLAN.
Increased security options
VLANs have the ability to provide additional security not available in a shared network environment. A switched network delivers packets only to the intended recipients and packets only to other members of the VLAN. This allows the network administrator to segment users requiring access to sensitive information into separate VLANs from the rest of the general users regardless of physical location.

8. VLAN Limitations
Device Limitations - VLAN can only support about 500 ethernet address per device.
Port Constraints - All ports on the hub/switch must be connected to VLAN.
This is a distribution of about 20 devices per port on a 25 port switch. In an ideal network situation, there is one device per port, for example, a printer, a workstation, and voice IP phone will require 3 ports. If you wanted to have one VLAN assignment for each port, then the maximum VLANs will equal 25.

9. LAN vs VLANs VLAN provide better performance when compared to LAN.
There is no need for physical administration for VLAN.
VLAN can handle more traffic by using less router compare to LAN.
The transmission of sensitive information on VLAN is much safer when compared to LAN.

10. When do I need a VLAN?
Consider using VLAN’s in any of the following situations:
Have more than 200 devices on your LAN
Have a lot of broadcast traffic on your LAN
Groups of users need more security or are being slowed down by too many broadcast?
Groups of users need to be on the same broadcast domain because they are running the same applications.
Make a single switch into multiple virtual switches.

11. Different types of VLANs
Cell-based VLANs
Used in ATM switched networks with LAN Emulation (LANE)
Allows hosts on traditional LAN segments to communicate using ATM networks without special hardware or software modifications
Frame-based VLANs
Used in Ethernet networks with frame tagging (primarily, IEEE and ISL- Inter Switch Link)
IEEE standard allows the use of VLANs with Ethernet, Token-Ring, and FDDI

12. VLAN Modes VLAN can be configured in three different ways:
VLAN switching mode.
VLAN translation mode.
VLAN routing mode.

13. VLAN Switching Mode
The VLAN forms a switching bridge in which frames are forwarded unmodified.

14. VLAN Translation Mode
Used when the packet needs to pass into a traditional or native interface that is not configured in a VLAN.
The packet VLAN frame is removed during this translation mode.

15. VLAN Routing Mode
Used when a packet needs to go from one VLAN to another VLAN.
Packet is modified by a router
Router places its MAC address into a packet as the source.
Changes packet’s VLAN ID.

16. Different VLAN definitions
Cisco VLAN
HP VLAN

17. References
Difference Between VLAN and LAN retrieved from
VLAN retrieved from
Virtual LAN - Benefits and Limitations retrieved from

18. Thank you for your time Any questions?