VLAN allOpen or allClosed Mode 169VLAN allOpen orallClosed ModeYou can select allOpen or allClosed as the VLAN mode for your entiresystem. The default is allOpen.3Com’s use of the term “allOpen” is equivalent to the IEEE Standard802.1Q term “Shared VLAN Learning” (SVL). The term “allClosed” isequivalent to the IEEE 802.1Q term “Independent VLAN Learning” (IVL).3Com imposes the restriction that you must choose one VLAN mode forthe entire system. More complex logic for assigning SVL and IVL toindividual ports is described in the IEEE 802.1Q standard.ImportantConsiderationsn In general, select your VLAN mode before you define your VLANs(VLANs with an origin of static).n As part of the configuration procedures for a router port IP interface,you must place the system in allClosed mode. Once you define arouter port IP interface (and the system creates the router port VLAN),you cannot change the VLAN mode until you delete the router port IPinterface.n Select the VLAN mode as follows:n allOpen — Use this less restrictive mode if you have no securityissues about the forwarding of data between VLANs. The allOpenmode is the default VLAN mode for all VLANs that you create. Itpermits data with a unicast MAC address to be forwardedbetween VLANs. For example, data received on IP VLAN 2 with adestination of IP VLAN 3 is forwarded there.The allOpen mode implies that the system uses a single bridgeaddress table for all of the VLANs on the system (the defaultconfiguration).n allClosed — Use this more restrictive mode if you are concernedabout security between VLANs. Data cannot be forwardedbetween VLANs (although data can still be routed betweenVLANs). The allClosed mode implies that each VLAN that youcreate has its own address table. Router port IP interfaces requireallClosed mode.
