BigIron RX Series Configuration Guide 29753-1001986-01VLAN groups 11There is a separate STP domain for each port-based VLAN. Routing occurs independently acrossport-based VLANs or STP domains. You can define each end of each backbone link as a separatetagged port-based VLAN. Routing will occur independently across the port-based VLANs. Becauseeach port-based VLAN’s STP domain is a single point-to-point backbone connection, you areguaranteed to never have an STP loop. STP will never block the virtual router interfaces within thetagged port-based VLAN, and you will have a fully routed backbone.A device offers the ability to create a virtual routing interface within a Layer 2 STP port-based VLANor within each IP protocol VLAN. This combination of multiple Layer 2 or Layer 3 broadcast domainsand virtual routing interfaces are the basis for Brocade’ very powerful Integrated Switch Routing(ISR) technology. ISR is very flexible and can solve many networking problems.VLAN groupsTo simplify VLAN configuration when you have many VLANs with the same configuration, you canconfigure VLAN groups. When you create a VLAN group, the VLAN parameters you configure for thegroup apply to all the VLANs within the group.The VLAN group feature allows you to create multiple port-based VLANs with identical portmembers. Since the member ports are shared by all the VLANs within the group, you must add theports as tagged ports. This feature not only simplifies VLAN configuration but also allows you tohave a large number of identically configured VLANs in a startup configuration file on the device’sflash memory module. Normally, a startup configuration file with a large number of VLANs mightnot fit on the flash memory module. By grouping the identically configured VLANs, you canconserve space in the startup configuration file so that it fits on the flash memory module.You can create up to 32 VLAN groupsNOTEDepending on the size of the VLAN ID range you want to use for the VLAN group, you might need toallocate additional memory for VLANs. To allocate additional memory, refer to “Allocating memoryfor more VLANs or virtual routing interfaces” on page 317.Configuring a VLAN groupTo configure a VLAN group, do the following.1. Create the VLAN group and assign the VLANs to that group.BigIron RX(config)# vlan-group 1 vlan 2 to 1000Syntax: [no] vlan-group vlan to Use 1 – 32 for parameter with the vlan-group command specifies the VLAN group IDand can be from.The vlan to parameters specify a continuous range (with no gaps) of VLANIDs that have not been configured in the CLI. Specify the low VLAN ID first and the high VLANID second. The command adds all the VLANs in the range to the VLAN group.If a VLAN within the range you specify is already configured, the CLI does not add the group butinstead displays an error message. If this happens, create the group by specifying a validcontiguous range that does not include the VLAN. Then add more VLANs to the group after theCLI changes to the configuration level for the group.
