364CHAPTER 14: VIRTUAL LANS (VLANS)

bridge vlan mode

3500

9000

9400

3900

9300

Determines whether data with a unicast MAC address can be forwarded between VLANs.

Valid Minimum Abbreviation

b v mode

Important Considerations

Select a VLAN mode as follows:

allOpen — Use this less restrictive mode if you do not have security issues concerning the forwarding of data between VLANs. It is the default VLAN mode for all VLANs that you create. It permits data with a unicast MAC address to be forwarded between VLANs. The allOpen mode implies that the system uses a single bridge address table for all of the VLANs on the system.

allClosed — Use this restrictive mode if you are concerned about security between VLANs. Data cannot be forwarded between VLANs but can still be routed between VLANs. This mode implies that each VLAN that you create has its own address table.

For the CoreBuilder 3500 system and CoreBuilder 9000 Layer 3 modules, if you are using allClosed mode and STP (with multiple routes to a destination), you can also use the command “bridge vlan stpMode” to disable STP blocking for a specified VLAN.

For the CoreBuilder 9000, set a VLAN mode for each switching module and the switch fabric module.

Changing this mode removes all VLANs and redefines the default VLAN.

Before you issue this command to change the mode, you must remove all routing interfaces, including router port IP interfaces. If routing interfaces are defined, the system displays this message:

could not change configured VLAN mode - interface in use by client.

Options

Prompt

Description

Possible Values

[Default]

 

 

 

 

 

VLAN mode

Selected VLAN mode for the entire

allOpen

allOpen

 

system

allClosed

(factory

 

 

default), or

 

 

 

 

current value

Page 364
Image 364
3Com 3500 manual Bridge vlan mode, Select a Vlan mode as follows