Lesson 10 — VLANs Flashcards
What is a VLAN?
Virtual Local Area Networks divide a single existing physical network into multiple logical networks
What is one key benefit of VLANs related to broadcast domains?
VLANs create smaller broadcast domains by dividing the LAN.
How do VLANs improve security?
Only users in the same VLAN can communicate with each other.
How do VLANs enhance IT efficiency?
Devices with similar requirements (e.g., faculty vs. students) can be grouped together.
How do VLANs reduce cost?
A single switch can support multiple groups or VLANs, reducing hardware needs.
How do VLANs improve network performance?
Smaller broadcast domains reduce traffic, which improves bandwidth.
How do VLANs simplify management?
Devices with similar roles often require similar apps and resources, making configuration easier.
What are the 3 different types of VLANs?
Data VLAN, Native VLAN, and Management VLAN
What is the Data VLAN used for?
It’s Dedicated to user-generated traffic (email and web traffic)
What is the Native VLAN used for?
This is used for trunk links only.
What is the Management VLAN used for?
This is used for SSH/Telnet VTY traffic and should not be carried with end user traffic.
What is the default Data VLAN on most switches?
VLAN 1, because all interfaces are initially assigned to it.
Are all frames on an 802.1Q trunk link tagged?
Yes—except for frames on the native VLAN.
Which VLAN typically acts as the SVI for Layer 2 switch management?
The Management VLAN.
What types of traffic are confined within a VLAN?
Unicast, multicast, and broadcast traffic.
Can devices in different VLANs communicate directly?
No, not without a Layer 3 device to route between VLANs.
What is required for communication between VLANs?
A Layer 3 device (e.g., a router or Layer 3 switch).
How many bytes is the IEEE 802.1Q VLAN tag header?
4 bytes.
What must happen to the FCS (Frame Check Sequence) when a VLAN tag is added?
It must be recalculated.
What must happen to the VLAN tag when the frame is sent to an end device?
The tag must be removed and the FCS recalculated to its original value.
What is the Type field in the 802.1Q tag and what is its value?
A 2-byte field with hexadecimal value 0x8100, called the Tag Protocol ID (TPID).
What is the User Priority field in an 802.1Q tag?
A 3-bit value used to support Quality of Service (QoS).
What is the Canonical Format Identifier (CFI) in the VLAN tag?
A 1-bit value used for compatibility with token ring frames on Ethernet.
What is the VLAN ID (VID) field in the tag?
A 12-bit identifier that supports up to 4096 VLANs.
