In this article we will refer only to Cisco platform switches like Catalyst series.
As a general case , freshers in networking domain (like CCNA aspirants etc.) tend to come across TRUNK and ACCESSterminologies in Switching.In most of Cisco switches, switchports are configured in “dynamic desirable” mode by default. This means if we connect a devices, it will negotiate to form a trunk.We can custom set switchports as either trunk or access mode since by letting default setting in place (the “dynamic desirable”), there will be less control on switch port behavior.
Trunk ports are generally used in switch to switch communication or switch to Router (Router on a stick). Trunks carry multiple Vlans across devices and maintain VLAN tags in Ethernet frames for receiving directly connected device differentiates between different Vlans.Access ports are part of only one VLAN and normally used for terminating end devices likes PC, Laptop and printer.
Using the “Switchport mode access” command forces the port to be an access port while and any device plugged into this port will only be able to communicate with other devices that are in the same VLAN.Using the “Switchport mode trunk” command forces the port to be trunk port.
Below table shares difference between Trunk port and Access port mode on Cisco Switches –