Beginning with Cisco Release 5.2(1) for Cisco Nexus 7000 Series devices, you can create Fibre Channel over Ethernet (FCoE) VLANs. For more information, see the Cisco NX-OS FCoE Configuration Guide for Cisco Nexus 7000 and Cisco MDS 9500.
You can use VLANs
to divide the network into separate logical areas at the Layer 2 level. VLANs can also be considered as broadcast domains.
Any switch port can belong to a VLAN, and unicast broadcast and multicast packets are forwarded and flooded only to end stations in that VLAN. Each VLAN is considered a logical network, and packets destined for stations that do not belong to the VLAN must be forwarded through a router.
A VLAN is a group of end
stations in a switched network that is logically segmented by function or
application, without regard to the physical locations of the users. VLANs have
the same attributes as physical LANs, but you can group end stations even if
they are not physically located on the same LAN segment.
Any switch port can belong to
a VLAN, and unicast, broadcast, and multicast packets are forwarded and flooded
only to end stations in that VLAN. Each VLAN is considered as a logical
network, and packets destined for stations that do not belong to the VLAN must
be forwarded through a router. The following figure shows VLANs as logical
networks. The stations in the engineering department are assigned to one VLAN,
the stations in the marketing department are assigned to another VLAN, and the
stations in the accounting department are assigned to another VLAN.
Figure 1. VLANs as Logically Defined
Networks
VLANs are usually associated
with IP subnetworks. For example, all the end stations in a particular IP
subnet belong to the same VLAN. To communicate between VLANs, you must route
the traffic.
By default, a newly created
VLAN is operational; that is, the newly created VLAN is in the no shutdown
condition. Additionally, you can configure VLANs to be in the active state,
which is passing traffic, or the suspended state, in which the VLANs are not
passing packets. By default, the VLANs are in the active state and pass
traffic.
A VLAN interface, or switched
virtual interface (SVI), is a Layer 3 interface that is created to provide
communication between VLANs. In order to route traffic between VLANs, you must
create and configure a VLAN interface for each VLAN. Each VLAN requires only
one VLAN interface.
Note
See the
for complete information on configuring VLAN interfaces, and subinterfaces, as
well as assigning IP addresses. This feature must be enabled before you can
configure VLAN interfaces.
VLAN Ranges
Note
The extended system ID is
always automatically enabled in Cisco NX-OS devices.
The device supports up to 4094
VLANs in accordance with the IEEE 802.1Q standard in each VDC. The software
organizes these VLANs into ranges, and you use each range slightly differently.
For information about configuration limits, see theverified scalability limits documentation for your switch.
This table describes the VLAN ranges.
Table 1 VLAN Ranges
VLANs Numbers
Range
Usage
1
Normal
Cisco 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—3967 and
4048—4093
Extended
You can create, name,
and use these VLANs. You cannot change the following parameters:
The state is
always active.
The VLAN is always
enabled. You cannot shut down these VLANs.
3968-4047 and 4094
Internally allocated
These 80 VLANs and
VLAN 4094 are allocated for internal device use. You cannot create, delete, or
modify any VLANs within the block reserved for internal use.
3968-4095
Note
4095 is reserved and unused as per 802.1Q standard.
Internally allocated
Beginning with Cisco release 5.2(1) for Cisco Nexus 7000 Series devices, VLANs 3968 to 4095 are reserved for internal use in each VDC by default.
You can change the reserved VLANs to any other 128 contiguous VLAN range. When you reserve such a range, it frees up the range of VLANs that were allocated for internal use by default, and all of those VLANs are available for user configuration except for VLAN 4095. All VDCs inherit the new reserved range of VLANs.
Note
VLAN 0 is reserved for 802.1p trafffic.
The software allocates a group
of VLAN numbers for features like multicast and diagnostics, that
need to use internal VLANs for their operation. You cannot use, modify, or
delete any of the VLANs in the reserved group. You can display the VLANs that
are allocated internally and their associated use.
Beginning with Cisco NX-OS Release 5.2(1), the system allocates a block of 128 reserved VLANs (3968 to 4094) for these internal uses. You can change the block of 128 reserved VLANs to occupy another range of 128 adjacent VLANs. For example, you can change the reserved block of VLANs to be 400 to 528. You cannot assign a previously created VLAN as part of the 128 range of reserved VLANs. Anytime you change the reserved block of VLANs for the device, you must do the following:
Enter the copy running-configuration startup-configuration command
Reload the device
Note
When you change the range of reserved VLANs, the existing configurations for the new range of VLANs get deleted. A warning note is displayed as in the following example:
switch(config)# system vlan 2000 reserve
This will delete all configs on vlans 2000-2127. Continue anyway? (y/n) [no] y
Note: After switch reload, VLANs 2000-2127 will be reserved for internal use.
This requires copy running-config to startup-config before
switch reload. Creating VLANs within this range is not allowed.
switch(config)#
To return to the default block of reserved VLANs (3968 to 4094), you must enter the no system reserve vlan command. The write-erase procedure does not restore the default reserved VLAN range to 3968 to 4094.
Creating, Deleting, and Modifying VLANs
Beginning with Cisco NX-OS Release 5.1(1) , you can configure a VLAN without actually creating the VLAN. This procedure is used for IGMP snooping, VTP, and other configurations.
Note
By default, all Cisco NX-OS
ports are Layer 3 ports.
VLANs are numbered from 1 to
4094 for each VDC. All ports that you have configured as switch ports belong to
the default VLAN when you first bring up the switch as a Layer 2 device. The
default VLAN (VLAN1) uses only default values, and you cannot create, delete,
or suspend activity in the default VLAN.
You create a VLAN by assigning
a number to it; you can delete VLANs and move them from the active operational
state to the suspended operational state. If you attempt to create a VLAN with
an existing VLAN ID, the device goes into the VLAN submode but does not create
the same VLAN again.
Newly created VLANs remain
unused until Layer 2 ports are assigned to the specific VLAN. All the ports are
assigned to VLAN1 by default.
Depending on the range of the
VLAN, you can configure the following parameters for VLANs (except the default
VLAN):
VLAN name
VLAN state
Shutdown or not shutdown
Beginning with Cisco NX-OS Release 6.1(1), you can configure VLAN long-names of up to 128 characters. To configure VLAN long-names, VTP must be in transparent or in off mode. If VTP is in client or server mode, the VLAN long-name feature cannot be enabled. For more details about VTP, see the Configuring VTP chapter.
Note
See the Cisco Nexus 7000 Series NX-OS Interfaces Configuration Guide
for information on configuring ports as VLAN access or trunk
ports and assigning ports to VLANs.
When you delete a specified
VLAN, the ports associated to that VLAN become inactive 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. The static MAC addresses and aging time for that VLAN are not
restored when the VLAN is reenabled.
Note
Commands entered in the VLAN
configuration submode are immediately executed. Beginning with Cisco release 5.1 for Nexus 7000 series devices, you must exit the VLAN configuration submode for configuration changes to take effect.
High Availability for VLANs
The software supports high
availability for both stateful and stateless restarts, as during a cold reboot,
for VLANs. For the stateful restarts, the software supports a maximum of three
retries. If you try more than 3 times within 10 seconds of a restart, the
software reloads the supervisor module.
You can upgrade or downgrade
the software seamlessly when you use VLANs.
Note
See the Cisco Nexus 7000 Series NX-OS High Availability and Redundancy Guide, for
complete information on high availability features.
Virtualization Support for VLANs
The software supports virtual
device contexts (VDCs), and VLAN configuration and operation are local to the
VDC.
Note
See the
Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide,
for complete information on VDCs and assigning resources.
Each VLAN must have all of its
ports in the same VDC. If you do not have enough resources allocated to the
VDC, the software returns an error message.
When you create a new VDC, the device automatically
creates a new default VLAN, VLAN1, and internally reserves VLANs for device use.
You can re-use the same numbers
for VLANs in different VDCs.
One or more VLANs can be
associated with a role to either allow or disallow the user to configure it.
When a VLAN is associated with a role, the corresponding interfaces will also
be subjected to the same check. For instance, if a role is allowed to access
VLAN1, then that role also has access to the interfaces that have that VLAN. If
an interface does not have the VLAN associated with a role, that interface is
not accessible to that role.
Licensing Requirements for VLANs
The following table shows the licensing requirements for this feature.
Product
License Requirement
Cisco NX-OS
VLANs require no license. Any feature not included in a license package is bundled with the Cisco NX-OS system images and is provided at no extra charge to you. For a complete explanation of the Cisco NX-OS licensing scheme, see the Cisco NX-OS Licensing Guide.
However, using VDCs requires an Advanced Services license.
Prerequisites for Configuring VLANs
VLANs have the following prerequisites:
You must be logged onto the device.
If necessary, install the Advanced Services license and enter the desired VDC. Ensure that you have allocated enough resources for that VDC. See the Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, for information on creating VDCs and allocating resources.
You must create the VLAN before you can do any modification of that VLAN.
Guidelines and Limitations for Configuring VLANs
VLANs have the following configuration guidelines and limitations:
The maximum number of VLANs per VDC is 4094.
You can reuse VLAN ID numbers in different VDCs. For example, you can have VLAN10 in the default VDC and a completely separate VLAN10 in a newly created VDC, such as VDC 2.
You can configure a single VLAN or a range of VLANs.
When you configure a large number of VLANs, first create the VLANs using the vlan command (for example, vlan200-300, 303-500). After the VLANS have been successfully created, name or configure those VLANs sequentially.
You cannot create, modify, or delete any VLANs that are within the group of VLANs reserved for internal use.
VLAN1 is the default VLAN. You cannot create, modify, or delete this VLAN.
VLANs 1006 to 4094 are always in the active state and are always enabled. You cannot suspend the state or shut down these VLANs.
Default Settings for VLANs
This table lists the default settings for VLAN parameters.
Table 2 Default VLAN Parameters
Parameters
Default
VLANs
Enabled
VLAN
VLAN1—A port is placed in VLAN1 when you
configure it as a switch port.
VLAN ID
1
VLAN name
Default VLAN (VLAN1)—default
All other VLANs—VLAN
vlan-id
VLAN state
Active
STP
Enabled; Rapid PVST+ is enabled
VTP
Disabled
VTP version
1
Configuring a VLAN
Note
See the Cisco Nexus 7000 Series NX-OS Interfaces Configuration Guide,
for information on assigning Layer 2 interfaces to VLANs (access or trunk
ports). All interfaces are in VLAN1 by default.
Note
If you are familiar with the
Cisco IOS CLI, be aware that the Cisco NX-OS commands for this feature might
differ from the Cisco IOS commands that you would use.
You can create or delete all VLANs except the default VLAN and those VLANs that are internally allocated for use by the device.
Once a VLAN is created, it is automatically in the active state.
Note
When you delete a VLAN, ports associated to that VLAN become inactive. Therefore, no traffic flows and the packets are dropped. On trunk ports, the port remains open and the traffic from all other VLANs except the deleted VLAN continues to flow.
If you create a range of VLANs and some of these VLANs cannot be created, the software returns a message listing the failed VLANs, and all the other VLANs in the specified range are created.
Note
You can also create and delete VLANs in the VLAN configuration submode.
Before You Begin
Ensure that you are in the correct VDC (or enter the switchto vdc command). You can repeat VLAN names and IDs in different VDCs, so you must confirm that you are working in the correct VDC.
SUMMARY STEPS
1.config t
2.vlan {vlan-id | vlan-range}
3.exit
4.
(Optional) show vlan
5.
(Optional) copy running-config startup-config
DETAILED STEPS
Command or Action
Purpose
Step 1
config t
Example:
switch# config t
switch(config)#
Enters configuration mode.
Step 2
vlan {vlan-id | vlan-range}
Example:
switch(config)# vlan 5
switch(config-vlan)#
Creates a VLAN or a range or VLANs. If you enter a number that is already assigned to a VLAN, the device puts you into the VLAN configuration submode for that VLAN. If you enter a number that is assigned to an internally allocated VLAN, the system returns an error message. However, if you enter a range of VLANs and one or more of the specified VLANs is outside the range of internally allocated VLANs, the command takes effect on only those VLANs outside the range. The range is from 2 to 4094; VLAN1 is the default VLAN and cannot be created or deleted. You cannot create or delete those VLANs that are reserved for internal use.
Copies the running configuration to the startup configuration.
This example shows how to create a range of VLANs from 15 to 20:
switch# config t
switch(config)# vlan 15-20
switch(config-vlan)#
Entering the VLAN Configuration Submode
To configure or modify the VLAN for the following parameters, you must be in the VLAN configuration submode:
Name
State
Shut down
Before You Begin
Ensure that you are in the correct VDC (or enter the switchto vdc command). You can repeat VLAN names and IDs in different VDCs, so you must confirm that you are working in the correct VDC.
SUMMARY STEPS
1.config t
2.vlan {vlan-id | vlan-range}
3.exit
4.
(Optional) show vlan
5.
(Optional) copy running-config startup-config
DETAILED STEPS
Command or Action
Purpose
Step 1
config t
Example:
switch# config t
switch(config)#
Enters configuration mode.
Step 2
vlan {vlan-id | vlan-range}
Example:
switch(config)# vlan 5
switch(config-vlan)#
Places you into the VLAN configuration submode. This submode allows you to name, set the state, disable, and shut down the VLAN or range of VLANs.
You cannot change any of these values for VLAN1 or the internally allocated VLANs.
Copies the running configuration to the startup configuration.
This example shows how to enter and exit the VLAN configuration submode:
switch# config t
switch(config)# vlan 15
switch(config-vlan)# exit
switch(config)#
Configuring a VLAN
To configure or modify a VLAN for the following parameters, you must be in the VLAN configuration submode:
Name
State
Shut down
Note
You cannot create, delete, or modify the default VLAN or the internally allocated VLANs. Additionally, some of these parameters cannot be modified on some VLANs.
Before You Begin
Ensure that you are in the correct VDC (or enter the switchto vdc command). VLAN names and IDs can be repeated in different VDCs, so you must confirm which VDC that you are working in.
SUMMARY STEPS
1.config t
2.vlan {vlan-id | vlan-range}
3.namevlan-name
4.state {active | suspend}
5.no shutdown
6.exit
7.
(Optional) show vlan
8.
(Optional) show vtp status
9.
(Optional) copy running-config startup-config
DETAILED STEPS
Command or Action
Purpose
Step 1
config t
Example:
switch# config t
switch(config)#
Enters configuration mode.
Step 2
vlan {vlan-id | vlan-range}
Example:
switch(config)# vlan 5
switch(config-vlan)#
Places you into the VLAN configuration submode. If the VLAN does not exist, the system creates the specified VLAN and then enters the VLAN configuration submode.
Step 3
namevlan-name
Example:
switch(config-vlan)# name accounting
Names the VLAN. You can enter up to 32 alphanumeric characters to name the VLAN. You cannot change the name of VLAN1 or the internally allocated VLANs. The default value is VLANxxxx where xxxx represent four numeric digits (including leading zeroes) equal to the VLAN ID number.
Step 4
state {active | suspend}
Example:
switch(config-vlan)# state active
Sets the state of the VLAN to active or suspend. While the VLAN state is suspended, the ports associated with this VLAN become inactive, and that VLAN does not pass any traffic. The default state is active. You cannot suspend the state for the default VLAN or VLANs 1006 to 4094.
Step 5
no shutdown
Example:
switch(config-vlan)# no shutdown
Enables the VLAN. The default value is no shutdown (or enabled). You cannot shut down the default VLAN, VLAN1, or VLANs 1006 to 4094.
Step 6
exit
Example:
switch(config-vlan)# exit
switch(config)#
Exits the VLAN configuration submode.
Step 7
show vlan
Example:
switch# show vlan
(Optional)
Displays information and status of VLANs.
Step 8
show vtp status
Example:
switch# show vtp status
(Optional)
Displays information and status of VLAN Trunking Protocols (VTPs).
Copies the running configuration to the startup configuration.
Note
Commands entered in the VLAN
configuration submode are immediately executed. Beginning with Cisco release 5.1 for Nexus 7000 series devices, you must exit the VLAN configuration submode for configuration changes to take effect.
This example shows how to configure optional parameters for VLAN 5:
switch# config t
switch(config)# vlan 5
switch(config-vlan)# name accounting
switch(config-vlan)# state active
switch(config-vlan)# no shutdown
switch(config-vlan)# exit
switch(config)#
Changing the Range of Reserved VLANs
To change the range of reserved VLANs, you must be in the configuration mode. After entering this command, you must do the following tasks:
Enter the copy running-config startup-config command
Reload the device
SUMMARY STEPS
1.switch# configure terminal
2.system vlanstart-vlanreserve
3.copy running-config startup-config
4.reload
5.
(Optional) show system vlan reserved
DETAILED STEPS
Command or Action
Purpose
Step 1
switch# configure terminal
Enters global configuration mode.
Step 2
system vlanstart-vlanreserve
Allows you to change the reserved VLAN range by specifying the starting VLAN ID for your desired range.
You can change the reserved VLANs to any other 128 contiguous VLAN range. When you reserve such a range, it frees up the range of VLANs that were allocated for internal use by default, and all of those VLANs are available for user configuration except for VLAN 4094. All VDCs inherit the new reserved range of VLANs.
Note
To return to the default range of reserved VLANs (3968-4094), you must enter the no system vlanstart-vlanreserve command.
Step 3
copy running-config startup-config
Copies the running configuration to the startup configuration.
Note
You must enter this command if you change the reserved block.
Step 4
reload
Reloads the software, and modifications to VLAN ranges become effective.
For more details about this command, see the .
Step 5
show system vlan reserved
(Optional)
Displays the configured changes to the VLAN range.
This example shows how to change the range of reserved VLANs:
switch# configuration terminal
switch(config)# system vlan 2000 reserve
This will delete all configs on vlans 2000-2127. Continue anyway? (y/n) [no] y
Note: After switch reload, VLANs 2000-2127 will be reserved for internal use.
This requires copy running-config to startup-config before
switch reload. Creating VLANs within this range is not allowed.
switch(config)#
Note
You must reload the device for this change to take effect.
Configuring a VLAN Before Creating the VLAN
Beginning with Cisco NX-OS Release 5.1(1), you can configure a VLAN before you create the VLAN. This procedure is used for IGMP snooping, VTP, and other configurations.
Note
The show vlan command does not display these VLANs unless you create it using the vlan command.
Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.
Step 4
show running-config vlan
Example:
switch(config)# show running-config vlan
Verifies that the system VLAN long-name feature is enabled.
This example shows how to enable VLAN long-names.
switch# configure terminal
switch(config)# system vlan long-name
switch(config)# copy running config startup config
switch(config)# show running-config vlan
Verifying the VLAN Configuration
To display VLAN configuration information, perform one of the
following tasks:
Command
Purpose
show running-config vlanvlan-id
Displays VLAN information.
show vlan [all-ports |
brief |
idvlan-id |
namename |
dot1q tag native]
Displays VLAN information.
show vlan summary
Displays a summary of VLAN information.
show vtp status
Displays VTP information.
show system vlan reserved
Displays system reserved VLAN range.
For information on the output of these commads, see the
Cisco Nexus 7000 Series NX-OS Layer 2 Switching Command Reference.
Displaying and Clearing VLAN Statistics
To display VLAN configuration information, perform one of the following tasks:
Command
Purpose
clear vlan
[idvlan-id]
counters
Clears counters for all VLANs or for a specified VLAN.
show vlan counters
Displays information on Layer 2 packets in each VLAN.
Configuration Example for VLANs
The following example shows how to create and name a VLAN as well as how to make the state active and administratively up:
switch# configure terminal
switch(config)# vlan 10
switch(config-vlan)# name test
switch(config-vlan)# state active
switch(config-vlan)# no shutdown
switch(config-vlan)# exit
switch(config)#
Additional References for VLANs -- CLI
Version
Related Documents
Related Topic
Document Title
Command reference
Cisco Nexus 7000 Series NX-OS Layer 2 Switching Command Reference
NX-OS Layer 2 switching
configuration
Cisco Nexus 7000 Series NX-OS Layer 2 Switching Configuration Guide
Interfaces, VLAN
interfaces, IP addressing, and port channels
Cisco Nexus 7000 Series NX-OS Interfaces Configuration Guide
Multicast routing
Cisco Nexus 7000 Series NX-OS Multicast Routing Configuration Guide
NX-OS fundamentals
Cisco Nexus 7000 Series NX-OS Fundamentals Configuration Guide
High availability
Cisco Nexus 7000 Series NX-OS High Availability and Redundancy Guide
System management
Cisco Nexus 7000 Series NX-OS System Management Configuration Guide
VDCs
Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide
Licensing
Cisco NX-OS Licensing Guide
Release notes
Cisco Nexus 7000 Series NX-OS Release Notes
Cisco Nexus 7000 Series NX-OS
Standards
Standards
Title
No new or modified
standards are supported by this feature, and support for existing standards has
not been modified by this feature.