Understanding Access Vlans - Cisco nexus 5000 series Configuration Manual

Configuring Access and Trunk Interfaces
and packet belong. This method allows packets that are encapsulated for several different VLANs to traverse
the same port and maintain traffic separation between the VLANs. The encapsulated VLAN tag also allows
the trunk to move traffic end-to-end through the network on the same VLAN.
Figure 6: Header Without and With 802.1Q Tag Included

Understanding Access VLANs

When you configure a port in access mode, you can specify which VLAN will carry the traffic for that interface.
If you do not configure the VLAN for a port in access mode, or an access port, the interface carries traffic for
the default VLAN (VLAN1).
You can change the access port membership in a VLAN by specifying the new VLAN. You must create the
VLAN before you can assign it as an access VLAN for an access port. If you change the access VLAN on an
access port to a VLAN that is not yet created, the system will shut that access port down.
Note If you change the VLAN on an access port or a trunk port it will flap the interface. However, if the port
is part of a vPC, then first change the native VLAN on the secondary vPC, and then to primary vPC.
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.
If you assign an access VLAN that is also a primary VLAN for a private VLAN, all access ports with that
Note
access VLAN will also receive all the broadcast traffic for the primary VLAN in the private VLAN mode.
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Cisco Nexus 5000 Series NX-OS Layer 2 Switching Configuration Guide, Release 5.1(3)N1(1)
Understanding Access VLANs
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