Understanding how VLAN Trunks work is essential to you passing
the CCNA Exam. In this post I’m going to talk about VLAN
Encapsulation with 802.1Q, and all the details about the VLAN
Trunking Protocol VTP. Trunks are needed in switching networks
with VLANs in order for hosts within different VLANs to still
communicate with each other. When you create a VLAN you are
supposed to maintain a 1 to 1 ratio with the number of subnets
you have. Which means if you have 4 VLANs you should also have 4
subnets. Since each VLAN is in a different subnet they are in
different networks and for devices in different networks to
communicate with one another a Layer 3 device such as a router
is needed. Interfaces on switches by default can only be
assigned to one VLAN at a time. So, in order for you to send
data about 4 different VLANs configured on a switch to a router
you need to configure an interface to be a trunk link. Trunk
links are able to send data for many different VLANs at one
time. In order to keep them from getting