VLAN

Virtual Local Area Network (VLAN’s) : 

Virtual Local Area Network (VLAN’s) P.SWATHI II-MCA 10043

Definition of Virtual Local Area Network : 

Definition of Virtual Local Area Network Commonly known as VLAN Group of hosts(ports) on the switch with a common set of requirements Group of hosts communicate as if they were attached to the same wire

VLAN : 

VLAN

VLAN Operations : 

VLAN Operations VLAN has a switched network that is logically segmented Each switch port can be assigned to a VLAN Ports assigned to the same VLAN share broadcasts. Ports that do not belong to that VLAN do not share these broadcasts This improves network performance because unnecessary broadcasts are reduced

How does it work? : 

How does it work? Bridge receives data from a workstation, it tags the data with a VLAN identifier (This is called explicit tagging) In implicit tagging the data is not tagged, VLAN determine the port on which the data arrived Tagging can be based on The port from which it came The source Media Access Control (MAC) field The source network address Or some other field or combination of fields

How does it work? (cont’d) : 

How does it work? (cont’d) VLANs are classified based on the method used The bridge would have to keep an updated database containing a mapping between VLANs’ and fields used for tagging To understand how VLAN's work, there is need to look at the types of VLAN

Cisco VLAN Trunking Protocol (VTP) : 

Cisco VLAN Trunking Protocol (VTP) VTP maintains VLAN configuration consistency across the entire network. VTP minimizes the possible configuration inconsistencies that arise when changes are made VTP provides a mapping scheme that enables seamless trunking within a network employing mixed-media technologies.

Protocol Based VLANs : 

Protocol Based VLANs Traffic is forwarded through ports based on protocol Traffic from any other protocol is not forwarded on the port

Private VLAN : 

Private VLAN VLAN contains switch ports that are restricted Each private VLAN typically contains many private ports, and a single uplink A typical application for a private VLAN is a hotel or Ethernet to the home network where each room or apartment has a port for Internet access.

Slide 10: 

Private VLAN

Mesh establishment : 

Mesh establishment There are two methods for full mesh establishment using BGP Label Distribution Protocol (LDP).

MAC address driven VLANs : 

MAC address driven VLANs User assigned based on MAC addresses Offers flexibility For Example:Since MAC addresses form a part of the workstation's network interface card, when a workstation is moved, no reconfiguration is needed to allow the workstation to remain in the same VLAN Impacts performance, scability, and administration

Benefits : 

Benefits Increased performance Decreased costs Virtual workgroups Security

What Are the Possible Attacks in a VLAN-Based Network? : 

What Are the Possible Attacks in a VLAN-Based Network? MAC Flooding Attack 802.1Q and ISL Tagging Attack Double-Encapsulated 802.1Q/Nested VLAN Attack

Conclusion : 

Conclusion It can be seen that creating and managing a VLAN can be quite a complex task The LAN administrator needs to have a clear understanding about how VLANs work We must know the commands needed in order to configure and set up the switches in his network.