Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 231)

• When LB mode is disabled for a port group, the same configured VF_Port to N_Port mapping
displays for the show running-config ag or show ag commands. This is because configured and
active mapping are the same.
• When LB mode is enabled for a port group, the show ag command displays the current, active
mapping because VF_Port to N_Port mapping is based on the current distributed load across all
N_Ports. The show running-config ag command displays the configured mapping only.
• If LB mode is enabled for a port group and a new N_Port comes online, existing logins are
undisturbed. If an N_Port is disabled, its existing logins are distributed to available ports to maintain a
balanced N_Port-to-VF_Port ratio.
• LB can be disabled using Network OS commands. When LB mode is disabled, VF_Ports are not
shared among N_Ports in the port group, but can only connect to N_Ports to which they are mapped.
If an N_Port is disabled, ENodes logged into mapped VF_Ports log out. As a best practice to ensure
device login, bind the ENode to a VF_Port and ensure that its mapped N_Port is online.
• LB mode is disruptive.
• If an N_Port is removed from a port group enabled for LB mode and moved to another port group,
the VF_Ports mapped to that N_Port remain with the N_Port.
This is not the case for port groups not enabled for LB mode. When you remove an N_Port from one
of these port groups, the VF_Ports mapped to the N_Port move to the default Port Group 0 along
with the N_Port. You can then move the N_Port to another group, but would need to re-map any
VF_Ports to the N_Port.
• If an N_Port is in a port group and then Automatic Login Balancing is enabled, the VF_Ports mapped
to the N_Port are distributed among online N_Ports in the same port group.
• You can disable or enable LB mode using the no modes lb or modes lb commands while in the port
group configuration mode. Refer to Enabling and disabling Login Balancing mode on page 231.
Enabling and disabling Login Balancing mode
Although Login Balancing (LB) mode is enabled by default when you create a port group, you can
disable and enable it using Network OS CLI commands.
Access Gateway and the PG policy must be enabled for this command to succeed.
Enable or disable LB mode using the no modes LB or modes lb commands while in the port group's
configuration mode.
1. Enter the configure terminal command to enter global configuration mode.
switch# configure terminal
2. Enter the rbridge-id id command to enter RBridge ID configuration mode for the specific switch.
switch(config)# rbridge-id 3
3. Enter the ag command to enter Access Gateway configuration mode.
switch(config-rbridge-id-3)# ag
4. Enter the port group ID, such as pg 8, to enter configuration mode for the port group.
switch(config-rbridge-id-3-ag)# pg 8
5. Perform one of the following steps:
• To enable LB mode, enter modes mode_name.
switch(config-rbridge-id-3-ag-pg-8)# modes lb
• To disable LB mode, enter no modes mode_name.
switch(config-rbridge-id-3-ag-pg-8)# no modes lb
Enabling and disabling Login Balancing mode
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