src: https://www.networkacademy.io/ccna/ethernet/vlan-concept

“Virtual” means not physically existing but appear to exist physically.

IEEE 802.1q standard and VLAN tagging and trunking basics.
IEEE 802.1q, often referred to as Dot1q, is the networking standard that supports VLANs on the Ethernet network.
VLAN’s are local to each switch and VLAN info is not passed between two switches. 

q).what is VLAN ?
ans)
*.VLAN is a logical network that can group devices/users regardless of their different physical locations.

q).who can create the VLAN?
*. A VLAN is created at the switch.

q).what if VLAN is not there?
q).what are potential problems associated with LAN incontext of VLAN?
ans).
*.one broadcast domain
Traffic congestion and poor performance
Security concerns

q).why we bring VLAN?
ans). To reduce broadcast domain.

Access port/untagged port
An access port carries traffic only for one VLAN
An access port sends or expects to receive untagged traffic

Trunk port/tagged port
To make different VLAN traffic travel across two switches, we need trunk.
A trunk is created by configuring trunk ports.
A trunk port sends or expects to receive tagged traffic.

q).what are the types of VLAN’s?
ans).
src :https://www.youtube.com/watch?v=tEM7fus03Ps

q).Can vlan10 device talk to vlan20 device with access port method ?
ans).
*.

q).what is default VLAN ?
ans).
*.VLAN 1 is default VLAN.
*.we can’t change/delete default VLAN
*.

q).what is native VLAN”?
ans)
—-

*.by default the native VLAN is VLAN 1 .but we can change it to any
  Number, such as VLAN 2, 20 or 99.
*.it can be configured on the trunk port.
*.A native VLAN  is a special VLAN whose traffic traverses on the 
 802.1q trunk without a VLAN tag.
*.the native VLAN should be the same on both ends of the trunk

q).is native VLAN and management VLAN same?
ans).
*.could be same, but a good security practice is they are not.

q).Is trunk link a special cable ?
ans).

*. NOOOO. 🙅
The reason that single link could become a “trunk” is not because of some Special physical cable . But simply becoz of configurations of switch ports on both ends of the link.

Q).how VLAN Tag works ?
Ans).
*.
The whole process👇 is tagging and trunking is done.

q).what is accessport ?
ans).

q).what is trunkport?
ans).
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