VLAN Configuration
This section describes how to configure a VLAN, and includes the following topics:
•
Configuring VLAN Characteristics
•Verifying a VLAN Configuration
Note For information about private VLANs, see Chapter 4, "Private VLAN Configuration."
Information About VLANs
Physical NICs are always assigned as trunk ports, which transmit either VLAN tagged or untagged packets. A vswitch can have the following VLAN configurations:
Physical ports are always trunk ports by default. The virtual machine interfaces can be either access ports or trunk ports. If a VEthernet interface is set as a trunk port, the VLAN is 4095.
VEthernet interfaces 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, are transmitted as untagged on the physical NIC interfaces. On the transmit side, this is equivalent to the native VLAN available in Cisco switches. When the VLAN is not specified, it is assumed to be 0.
Table 3-1 summarizes the actions taken on packets recieved by the virtual ethernet module (VEM) based on VLAN tagging.
Guidelines and Limitations
This section includes the following topics:
•Maximum Allowed VLANs and MAC Addresses per VLAN
•How Cisco Nexus 1000V VLANs are Numbered
Maximum Allowed VLANs and MAC Addresses per VLAN
Table 3-2 lists the Cisco Nexus 1000V VLAN and MAC address limitations.
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Number of active VLANs |
512 |
MAC addresses per VLAN within a VEM |
1024 |
How Cisco Nexus 1000V VLANs are Numbered
In accordance with the IEEE 802.1Q standard, up to 4094 VLANs (numbered 1-4094) are supported in Cisco Nexus 1000V, and are organized as shown in Table 3-3.
Note For information about diagnostics, see the document,
Cisco Nexus 1000V System Management Configuration Guide, Release 4.0(4)SV1(1).
Creating a VLAN
Use this procedure to do one of 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.
BEFORE YOU BEGIN
Before beginning this procedure, you must know or do the following:
Note All interfaces and all ports configured as switchports are in VLAN 1 by default.
Note Be aware that the NX-OS commands may differ from those used in Cisco IOS.
•You are logged in to the CLI in EXEC mode.
•VLAN characteristics are configured in the VLAN submode. To configure a VLAN that is already created, see the procedure, Configuring VLAN Characteristics.
•You are familiar with the section, How Cisco Nexus 1000V VLANs are Numbered.
•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.
•For information about the following, see the document, Cisco Nexus 1000V Interface Configuration Guide, Release 4.0(4)SV1(1).
–Assigning Layer 2 interfaces to VLANs (access or trunk ports).
–Configuring ports as VLAN access or trunk ports and assigning ports to VLANs.
SUMMARY STEPS
1. config t
2. show vlan
3. {no}vlan {vlan-id | vlan-range}
4. exit
5. show vlan id <vlan-id>
6. copy running-config startup-config
DETAILED STEPS
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Step 1 |
config t Example: n1000v# config t n1000v(config)# |
Places you in CLI Global Configuration mode. |
Step 2 |
show vlan Example: n1000v(config)# show vlan |
Displays the VLANs that already exist. |
Step 3 |
|
Creates or deletes, and saves in the running configuration, a VLAN or a range or VLANs. To configure the VLAN, see the procedure, Configuring VLAN Characteristics. Note Note Note |
Example: n1000v(config)# vlan 5 n1000v(config-vlan)# |
This example shows VLAN 5 being created. The VLAN is activated and you are automatically placed into a submode for configuring VLAN 5. |
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Example: n1000v# config t n1000v(config)# vlan 15-20 n1000v(config-vlan)# |
This example shows the range, VLAN 15-20, being created. The VLANs in the range are activated, and you are automatically placed into a submode for configuring VLAN 15-20. Note |
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Example: n1000v(config)# no vlan 3967 n1000v(config)# |
This example shows VLAN 3967 being deleted, using the no form of the command. |
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Step 4 |
exit Example: n1000v(config-vlan)# exit n1000v(config)# |
Exits the VLAN mode and returns you to CLI GLobal Configuration mode. |
Step 5 |
show vlan id 5 Example: n1000v(config)# show vlan id 5 |
(Optional) Displays the VLAN configuration. |
Step 6 |
copy running-config startup-config Example: n1000v(config)# copy running-config startup-config |
(Optional) Saves the running configuration persistently through reboots and restarts by copying it to the startup configuration. |
Example:
n1000v# config t
n1000v(config)# vlan 5
n1000v(config-vlan)# exit
n1000v(config)# 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)# copy run start
[########################################] 100%
n1000v(config)#
Configuring VLAN Characteristics
Use this procedure to configure the following for a VLAN that has already been created:
•Name the VLAN.
•The operational state (active, suspend) of the VLAN.
•The VLAN media type (Ethernet).
•Shut down switching on the VLAN.
BEFORE YOU BEGIN
Before beginning this procedure, you must know or do the following:
•Some characteristics cannot be modified on some VLANs. For more information, see the "How Cisco Nexus 1000V VLANs are Numbered" section.
Note Commands entered in the VLAN configuration submode are immediately saved to the running configuration.
SUMMARY STEPS
1. config t
2. vlan {vlan-id | vlan-range}
3. name vlan-name
4. state {active | suspend}
5. no shutdown
6. exit
7. show vlan id
8. copy running-config startup-config
DETAILED STEPS
Example:
n1000v# config t
n1000v(config)# vlan 5
n1000v(config-vlan)# name accounting
n1000v(config-vlan)# state active
n1000v(config-vlan)# no shutdown
n1000v(config-vlan)# exit
n1000v(config)# show vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Eth2/1, Eth2/2, Eth2/3, Eth2/5
Eth2/7, Eth2/8, Eth2/9, Eth2/10
Eth2/15, Eth2/21, Eth2/22
Eth2/23, Eth2/24, Eth2/25
Eth2/46, Eth2/47, Eth2/48
5 accounting active
6 VLAN0006 active
7 VLAN0007 active
8 test active
9 VLAN0009 active
10 VLAN0010 active
50 VLAN0050 active Eth2/6
100 trunked active
200 VLAN0200 active
201 VLAN0201 active
202 VLAN0202 active
3966 VLAN3966 active
n1000v(config)#
Verifying a VLAN Configuration
Use the following commands to display and verify a VLAN configuration.
Example:
n1000v(config)# show vlan summary
Number of existing VLANs : 13
Number of existing user VLANs : 12
Number of existing extended VLANs : 1
n1000v(config)#
Additional References
For additional information related to implementing VLANs, see the following sections:
Related Documents
Standards
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No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
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Feature History for VLANs
This section provides the VLAN release history.
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VLANs |
4.0(4)SV1(1) |
This feature was introduced. |
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