VLANs Flashcards
Learn the role of VLANs
What are VLANs?
VLAN = Subnet
Allows you to break up a physical switch into smaller virtual mini switches.
VLANs can be spread across different switches.
All hosts in a VLAN have addresses in the same subnet. The switch the VLANs are configured on have a separate MAC address table for each VLAN.
What are the benefits of VLANs
- Improved security
- Cost reductions
- Higher performance
- Broadcast stop migration
- Simple to manage
How is information about a VLAN stored?
Stored in the VLAN database in flash memory on the switch it is implemented on
What are the different types of VLANs?
- Data/User VLAN
- Voice VLAN
- Management VLAN
- Native VLAN
- Default VLAN
Explain what a data VLAN is
Used to carry files, e-mails, shared application traffic, and user traffic.
A separate VLAN is used for each group of users e.g student, staff, management
Explain the a native VLAN is
The one VLAN that can travers trunk/access ports without tagging data.
If data arrives at the switch without a tag then the data is sent to this VLAN
Designed for backwards compatibility where devices don’t have knowledge of tagging.
Explain what a default VLAN is
If no VLANs are configured all ports belong to this VLAN. In other words all ports default to this VLAN
VLAN 1 on Cisco switches.
What is Trunking?
Rather than having multiple links for VLANs on the same switch. Trunk (reduce) down to one link.
What is Frame Tagging in relation to Trunking.
A tag is added to the frame to know which VLAN it came from.
The tag is removed when it leaves the trunk.
The standard is IEEE 802.1Q
What is Dynamic Trunking Protocol (DTP)?
DTP manages trunk negotiation but only if ports on other switches are configured with DTP
Cisco developed protocol. Switches from other vendors do not support DTP.
