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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 an access VLAN to the packet. |
Trunk |
Tagged |
No action is taken on the packet. |
Trunk |
Untagged |
The VEM adds a native VLAN tag to the packet. |
VLAN configuration has the following guidelines and limitations:
You configure VLANs through OpenStack as a VM subnet.
You must consistently use OpenStack for all VM network and subnet configuration. If you use both OpenStack and the VSM to configure VM networks and subnets, the OpenStack and the VSM configurations can become out-of-sync and result in faulty or inoperable network deployments.
In accordance with the IEEE 802.1Q standard, Cisco Nexus 1000V can use the VLANs within the range of 1-4094 (see 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. For information about diagnostics, see the Cisco Nexus 1000V for KVM System Management Configuration Guide. |
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
You must configure VLANs as VM subnets using the OpenStack Horizon Dashboard or the OpenStack CLI.
You must consistently use OpenStack for all VM network and subnet configuration. If you use both OpenStack and the VSM to configure VM networks and subnets, the OpenStack and the VSM configurations can become out-of-sync and result in faulty or inoperable network deployments.
Use this procedure to do the following:
Create a single VLAN that does not already exist.
Create a range of VLANs that do not already exist.
Delete an existing VLAN.
Note | All interfaces and all ports configured as switchports are in VLAN 1 by default. |
You are logged in to the CLI in EXEC mode.
VLAN characteristics are configured in the VLAN configuration mode.
You are familiar with the VLAN numbering.
Newly-created VLANs remain unused until Layer 2 ports are assigned to them.
When you delete a specified VLAN, the ports associated to that VLAN are shut down and no traffic flows. When you delete a specified VLAN from a trunk port, only that VLAN is shut down and traffic continues to flow on all the other VLANs through the trunk port. However, the system retains all the VLAN-to-port mapping for that VLAN, and when you reenable, or re-create, that specified VLAN, the system automatically reinstates all the original ports to that VLAN. Note that the static MAC addresses and aging time for that VLAN are not restored when the VLAN is reenabled.
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)#
The following example displays the VLAN 5 configuration:
switch# configure terminal switch(config)# vlan 5 switch(config-vlan)# show vlan id 5 VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 5 VLAN0005 active VLAN Type ---- ----- 5 enet Remote SPAN VLAN ---------------- Disabled Primary Secondary Type Ports ------- --------- --------------- ------------------------------------------- n1000v(config-vlan)# copy run start [########################################] 100% n1000v(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. | ||
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:
| ||
Step 6 | switch(config-vlan)# show vlan [ id vlan-id ] | (Optional)
Displays the VLAN configuration. | ||
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
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active
5 VLAN0005 active
2166 VLAN2166 active
2167 VLAN2167 active
2168 VLAN2168 active
2169 VLAN2169 active
2170 VLAN2170 active
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 |
Release |
Description |
---|---|---|
VLANs |
Release 5.2(1)SK1(2.1) |
This feature was introduced |