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This chapter contains the following sections:
vEthernet interfaces that are assigned to specific VLANs are tagged with the VLAN when transmitted. A vEthernet interface that is not assigned to a specific VLAN, or assigned to VLAN 0, is transmitted as untagged on the physical NIC interfaces. When the VLAN is not specified, it is assumed to be 1.
The following table summarizes the actions taken on packets that are received by the Virtual Ethernet Module (VEM) based on VLAN tagging.
Port Type | Packet received | Action |
---|---|---|
Access |
Tagged |
The packet is dropped. |
Access |
Untagged |
The VEM adds access VLAN to the packet. |
Trunk |
Tagged |
No action is taken on the packet. |
Trunk |
Untagged |
The VEM adds native VLAN tag to packet. |
In accordance with the IEEE 802.1Q standard, up to 128 VLANs are supported in Cisco Nexus 1000V and the valid range is 1-4094, and are organized in the following table:
VLANs Numbers | Range | Usage |
---|---|---|
1 |
Normal |
Cisco Nexus 1000V default. You can use this VLAN, but you cannot modify or delete it. |
2–1005 |
Normal |
You can create, use, modify, and delete these VLANs. |
1006-4094 |
Extended |
You can create, name, and use these VLANs. You cannot change the following parameters: The extended system ID is always automatically enabled. |
3968-4047 and 4094 |
Internally allocated |
You cannot use, create, delete, or modify these VLANs. You can display these VLANs. Cisco Nexus 1000V allocates these 80 VLANs, plus VLAN 4094, for features, like diagnostics, that use internal VLANs for their operation. |
Note |
For information about diagnostics, see the document, . |
Parameters | Default |
---|---|
VLAN assignment for all interfaces and all ports configured as switchports |
VLAN 1 |
VLAN name |
VLANxxxx where xxxx represent four numeric digits (including leading zeroes) equal to the VLAN ID number |
Shut state |
No shutdown |
Operational state |
Active |
External switch tagging (EST) |
Enabled |
IGMP snooping |
Enabled |
Configuring a VLAN
Use this procedure to do one of the following:
Note |
All interfaces and all ports configured as switchports are in VLAN 1 by default. |
Note |
Be aware that the Cisco NX-OS commands may differ from those used in Cisco IOS. |
In the following example VLAN 5 is created and you are automatically placed into the VLAN configuration mode for VLAN 5:
switch# configure terminal switch(config)# vlan 5 switch(config-vlan)#
The following example shows the range, VLAN 15-20, being created. The VLANs in the range are activated, and you are automatically placed into VLAN configuration mode for VLANs 15-20.
Note |
If you create a range of VLANs that includes an unusable VLAN, all VLANs in the range are created except those that are unusable; and Cisco Nexus 1000V returns a message listing the failed VLANs. |
switch# configure terminal switch(config)# vlan 15-20 switch(config-vlan)#
The following example shows VLAN 3967 being deleted, using the no form of the command:
switch# configure terminal switch(config)# no vlan 3967 switch(config)#
Use this procedure to configure the following for a VLAN that has already been created:
Note |
Commands entered in the VLAN configuration mode are immediately saved to the running configuration. |
Note |
Some characteristics cannot be modified on some VLANs. For more information, see the VLAN numbering described in the Guidelines and Limitationssection. |
Command or Action | Purpose | |||
---|---|---|---|---|
Step 1 | switch# configure terminal | Enters global configuration mode. |
||
Step 2 | switch(config)# vlan { vlan-id | vlan-range } | Enters VLAN configuration mode for the specified VLAN.
|
||
Step 3 | switch(config-vlan)# name vlan-name | Adds a name to the VLAN of up to 32 alphanumeric characters. |
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Step 4 | switch(config-vlan)# state { active | suspend } | Changes the operational state of the VLAN and saves it in the running configuration. Allowable entries are: While the VLAN state is suspended, the ports associated with this VLAN are shut down, and that VLAN does not pass any traffic.
|
||
Step 5 | switch(config-vlan)# no shutdown | Enables VLAN switching in the running configuration. Allowable entries are:
|
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Step 6 | switch(config-vlan)# show vlan [ id vlan-id ] | (Optional) Displays the VLAN configuration. |
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Step 7 | switch(config-vlan)# copy running-config startup-config | (Optional) Saves the running configuration persistently through reboots and restarts by copying it to the startup configuration. |
n1000v# configure terminal
n1000v(config)# vlan 5
n1000v(config-vlan)# name accounting
n1000v(config-vlan)# state active
n1000v(config-vlan)# no shutdown
n1000v(config-vlan)# show vlan brief
Use one of the following commands to verify the configuration:
Command | Purpose |
---|---|
show running-config vlan vlan-id |
Displays VLAN information in the running configuration. |
show vlan [ all-ports | brief | id vlan-id | name name | dot1q tag native ] |
Displays the specified VLAN information. |
show vlan summary |
Displays a summary of VLAN information. |
Feature Name |
Feature Name |
Releases |
---|---|---|
VLANs |
Release 5.2(1)IC1(1.1) |
This feature was introduced |