Switch Ports; Access Ports; Trunk Ports - Cisco Catalyst 2360 Software Configuration Manual

Understanding Interface Types
VLAN partitions provide hard firewalls for traffic in the VLAN, and each VLAN has its own MAC
address table. A VLAN comes into existence when a local port is configured to be associated with the
VLAN, when the VLAN Trunking Protocol (VTP) learns of its existence from a neighbor on a trunk, or
when a user creates a VLAN.
To configure normal-range VLANs (VLAN IDs 1 to 1005), use the vlan vlan-id global configuration
command to enter config-vlan mode or the vlan database privileged EXEC command to enter VLAN
database configuration mode. The VLAN configurations are saved in the VLAN database.
To configure extended-range VLANs (VLAN IDs 1006 to 4094), you must use config-vlan mode with
VTP mode set to transparent. Extended-range VLANs are not added to the VLAN database. When VTP
mode is transparent, the VTP and VLAN configuration is saved in the switch running configuration. You
can save it in the switch startup configuration file by entering the copy running-config startup-config
privileged EXEC command.
Add ports to a VLAN by using the switchport interface configuration commands:
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Switch Ports

Switch ports are Layer 2-only interfaces associated with a physical port. Ports belong to one or more
VLANs. You can configure a port as an access port or trunk port or let the Dynamic Trunking Protocol
(DTP) operate on a per-port basis to set the switchport mode by negotiating with the port on the other
end of the link. Switch ports are used for managing the physical interface and associated Layer 2
protocols.
Configure switch ports by using the switchport interface configuration commands. Use the switchport
command with no keywords to put an interface that is in Layer 3 mode into Layer 2 mode.
For information about configuring access port and trunk port characteristics, see
"Configuring VLANs."

Access Ports

An access port belongs to and carries the traffic of only one VLAN. Traffic is received and sent in native
formats with no VLAN tagging. Traffic arriving on an access port is assumed to belong to the VLAN
assigned to the port. If an access port receives a tagged packet (802.1Q), the packet is dropped, and the
source address is not learned.
You manually assign static access ports to a VLAN.

Trunk Ports

A trunk port carries the traffic of multiple VLANs and by default is a member of all VLANs in the VLAN
database. A trunk port supports simultaneous tagged and untagged traffic. The port is assigned a default
port VLAN ID (PVID), and all untagged traffic travels on the port default PVID. All untagged traffic
Catalyst 2360 Switch Software Configuration Guide
8-2
Identify the interface.
For a trunk port, set trunk characteristics, and, if desired, define the VLANs to which it can belong.
For an access port, set and define the VLAN to which it belongs.
Chapter 8 Configuring Interface Characteristics
Chapter 9,
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