Brocade BigIron RX Series Configuration Guide - Manual (Page 377)

BigIron RX Series Configuration Guide 299
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VLAN groups
11
When designing an ISR network, pay attention to your use of virtual routing interfaces and the
spanning-tree domain. If Layer 2 switching of your routed protocols (IP, IPX, AppleTalk) is not
required across the backbone, then the use of virtual routing interfaces can be limited to edge
switch ports within each router. Full backbone routing can be achieved by configuring routing on
each physical interface that connects to the backbone. Routing is independent of STP when
configured on a physical interface.
If your ISR design requires that you switch IP, IPX, or Appletalk at Layer 2 while simultaneously
routing the IP protocol over a single backbone, then create multiple port-based VLANs and use
VLAN tagging on the backbone links to separate your Layer 2 switched and Layer 3 routed
networks.
There is a separate STP domain for each port-based VLAN. Routing occurs independently across
port-based VLANs or STP domains. You can define each end of each backbone link as a separate
tagged port-based VLAN. Routing will occur independently across the port-based VLANs. Because
each port-based VLAN’s STP domain is a single point-to-point backbone connection, you are
guaranteed to never have an STP loop. STP will never block the virtual router interfaces within the
tagged 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 VLAN
or within each IP protocol VLAN. This combination of multiple Layer 2 or Layer 3 broadcast domains
and 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 groups
To simplify VLAN configuration when you have many VLANs with the same configuration, you can
configure VLAN groups. When you create a VLAN group, the VLAN parameters you configure for the
group apply to all the VLANs within the group.
The VLAN group feature allows you to create multiple port-based VLANs with identical port
members. Since the member ports are shared by all the VLANs within the group, you must add the
ports as tagged ports. This feature not only simplifies VLAN configuration but also allows you to
have a large number of identically configured VLANs in a startup configuration file on the device’s
flash memory module. Normally, a startup configuration file with a large number of VLANs might
not fit on the flash memory module. By grouping the identically configured VLANs, you can
conserve space in the startup configuration file so that it fits on the flash memory module.
You can create up to 32 VLAN groups
NOTE
Depending on the size of the VLAN ID range you want to use for the VLAN group, you might need to
allocate additional memory for VLANs. To allocate additional memory, refer to
“Allocating memory
for more VLANs or virtual routing interfaces” on page 319.
Configuring a VLAN group
To 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 1000
Syntax: [no] vlan-group <num> vlan <vlan-id> to <vlan-id>