Configuring Access and Trunk Interfaces
Ethernet interfaces can be configured either as access ports or trunk ports. Trunks carry the traffic of multiple
VLANs over a single link and allow you to extend VLANs across the network.
Note
Cisco NX-OS supports only IEEE 802.1Q-type VLAN trunk encapsulation.
This chapter describes the configuration of access or trunk ports on Cisco Nexus 3000 Series switches. It
includes the following sections:
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Information About Access and Trunk Interfaces
Understanding Access and Trunk Interfaces
Ethernet interfaces can be configured either as access ports or a trunk ports, as follows:
• An access port can have only one VLAN configured on the interface; it can carry traffic for only one
• A trunk port can have two or more VLANs configured on the interface; it can carry traffic for several
In order to correctly deliver the traffic on a trunk port with several VLANs, the device uses the IEEE 802.1Q
encapsulation or tagging method.
To optimize the performance on access ports, you can configure the port as a host port. Once the port is
configured as a host port, it is automatically set as an access port.
If an access port receives a packet with an 802.1Q tag in the header other than the access VLAN value, that
port drops the packet without learning its MAC source address.
Information About Access and Trunk Interfaces, page 45
Configuring Access and Trunk Interfaces, page 48
Verifying Interface Configuration, page 53
VLAN.
VLANs simultaneously.
Cisco Nexus 3000 Series NX-OS Layer 2 Switching Configuration Guide, Release 5.0(3)U1(1)
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