Enabling/Disabling Spanning Tree For A Vlan; Enabling/Disabling Vlan Authentication; Enabling/Disabling Spanning Tree For A Vlan" On Page - Alcatel OmniSwitch 6624 Network Configuration Manual

Enabling/Disabling Spanning Tree for a VLAN

Enabling/Disabling Spanning Tree for a VLAN
When a VLAN is created, an 802.1D standard Spanning Tree Algorithm and Protocol (STP) instance is
enabled for the VLAN by default. The spanning tree operating mode set for the stack determines how
VLAN ports are evaluated to identify redundant data paths.
If the Spanning Tree switch operating mode is set to flat, then VLAN port connections are checked against
other VLAN port connections for redundant data paths. In this mode, if the STP instance for VLAN 1 is
disabled, then it is disabled for all configured VLANs. However, disabling STP on a VLAN other than
VLAN 1 does not exclude that VLAN's ports from the flat STP algorithm.
If the Spanning Tree operating mode is set to 1x1, there is a single Spanning Tree instance for each VLAN
broadcast domain. Enabling or disabling STP on a VLAN in this mode will include or exclude the VLAN
from the 1x1 STP algorithm.
The vlan stp command is used to enable/disable a Spanning Tree instance for an existing VLAN. In the
following examples, Spanning Tree is disabled on VLAN 255 and enabled on VLAN 755:
-> vlan 255 stp disable
-> vlan 755 stp enable
STP does not become operationally active on a VLAN unless the VLAN is operationally active, which
occurs when at least one active port is assigned to the VLAN. Also, STP is enabled/disabled on individual
ports. So even if STP is enabled for the VLAN, a port assigned to that VLAN must also have STP enabled.
See Chapter 5, "Configuring Spanning Tree Parameters."

Enabling/Disabling VLAN Authentication

Layer 2 authentication uses VLAN membership to grant access to network resources. Authenticated
VLANs control membership through a log-in process; this is sometimes called user authentication. A
VLAN must have authentication enabled before it can participate in the Layer 2 authentication process.
To enable/disable authentication on an existing VLAN, use the
ple, the following commands enable authentication on VLAN 955 and disable it on VLAN 455:
-> vlan 955 authentication enable
-> vlan 455 authentication disable
Once authentication is enabled on a VLAN, then only authenticated mobile port devices can join the
VLAN after completing the appropriate log-in process. To enable authentication on a mobile port, use the
vlan port authenticate
authentication for Alcatel switches, see
uring Authenticated VLANs."
page 4-10
command. For more information about mobile port commands and Layer 2
Chapter 6, "Assigning Ports to VLANs,"
OmniSwitch 6624/6648 Network Configuration Guide
vlan authentication command. For exam-
and Chapter 18, "Config-
Configuring VLANs
April 2004