Creating/Modifying Vlans; Adding/Removing A Vlan - Alcatel OmniSwitch 6800 Series Network Configuration Manual

Configuring VLANs

Creating/Modifying VLANs

The initial configuration for all Alcatel switches consists of a default VLAN 1 and all switch ports are
initially assigned to this VLAN. When a switching module is added to the switch, the module's physical
ports are also assigned to VLAN 1. If additional VLANs are not configured on the switch, then the entire
switch is treated as one large broadcast domain. All ports will receive all traffic from all other ports.
Up to 1024 VLANs are supported per stack, including default VLAN 1. In compliance with the IEEE
802.1Q standard, each VLAN is identified by a unique number, referred to as the VLAN ID. The user spec-
ifies a VLAN ID to create, modify or remove a VLAN and to assign switch ports to a VLAN. When a
packet is received on a port, the port's VLAN ID is inserted into the packet. The packet is then bridged to
other ports that are assigned to the same VLAN ID. In essence, the VLAN broadcast domain is defined by
a collection of ports and packets assigned to its VLAN ID.
A VLAN's operational status remains inactive until at least one active switch port is assigned to the
VLAN. This means that VLAN properties, such as Spanning Tree or router ports, also remain inactive.
Ports are considered active if they are connected to an active network device. Non-active port assign-
ments are allowed, but do not change the VLAN's operational state.
Ports are either statically or dynamically assigned to VLANs. When a port is assigned to a VLAN, a
VLAN port association (VPA) is created and tracked by VLAN management switch software. For more
information about VPAs, see
Ports to VLANs."

Adding/Removing a VLAN

To add a VLAN to the switch configuration, enter vlan followed by a unique VLAN ID number between
2 and 4094, an optional administrative status, and an optional description. For example, the following
command creates VLAN 755 with a description:
-> vlan 755 enable name "IP Finance Network"
By default, administrative status and Spanning Tree are enabled when the VLAN is created and the VLAN
ID is used for the description if one is not specified. Note that quotation marks are required if the descrip-
tion contains multiple words separated by spaces. If the description consists of only one word or multiple
words separated by another character, such as a hyphen, then quotes are not required.
To remove a VLAN from the switch configuration, use the no form of the vlan command.
-> no vlan 755
When a VLAN is deleted, any router ports defined for the VLAN are removed and all VLAN port associa-
tions are dropped. For more information about VLAN router ports, see
on page 4-11.
Note that up to 254 Spanning Tree instances per switch are supported in the 1x1 Spanning Tree mode.
Since each VLAN with Spanning Tree enabled uses one of these instances, only 254 VLANs can have an
active Spanning Tree instance at any given time.
To create more than 254 VLANs on a switch running in the 1x1 Spanning Tree mode, use the vlan stp
disable, vlan 1x1 stp disable, or vlan flat stp disable command to create a VLAN with Spanning Tree
disabled. See "Enabling/Disabling Spanning Tree for a VLAN" on page 4-10
To view a list of VLANs already configured on the switch, use the
the VLAN Configuration" on page 4-15
OmniSwitch 6800 Series Network Configuration Guide
"Defining VLAN Port Assignments" on page 4-6
for more information.
November 2004
Creating/Modifying VLANs
and Chapter 6, "Assigning
"Configuring VLAN Router Ports"
for more information.
show vlan command. See "Verifying
page 4-5