Information About Vlans; Understanding Vlans; Vlan Ranges - Cisco Nexus 7000 Series Configuration Manual

Information About VLANs

Information About VLANs

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.

Understanding VLANs

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.
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.

VLAN Ranges

The extended system ID is always automatically enabled in Cisco NX-OS devices.
Note
The device supports up to 4094 VLANs in accordance with the IEEE 802.1Q standard. The software organizes
these VLANs into ranges, and you use each range slightly differently.
For information about configuration limits, see the documentation for your switch.
This table describes the VLAN ranges.
Table 3: VLAN Ranges
VLANs Numbers
1
Cisco Nexus 7000 Series NX-OS Layer 2 Switching Configuration Guide, Release 5.x
24
Range
Normal
Configuring VLANs
Usage
Cisco default. You can use this
VLAN, but you cannot modify or
delete it.