Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 197)

Multi-Service IronWare Switching Configuration Guide 167
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VLAN configuration rules
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Protocol-based VLANs can be configured to have static or excluded port memberships. Static ports
are permanent members of a protocol-based VLAN. They remain active members of the
protocol-based VLAN regardless of whether they receive traffic for the VLAN’s protocol.
NOTE
The dynamic port membership is not supported on Brocade devices.
If you want to exclude certain ports in a port-based VLAN from protocol-based VLANs, the
protocol-based VLAN can be explicitly configured to exclude those ports.
VLAN configuration rules
To create any type of VLAN on a Brocade router, Layer 2 forwarding must be enabled. When Layer 2
forwarding is enabled, the Brocade device becomes a switch on all ports for all non-routable
protocols.
In addition to this rule, the sections below summarize the rules for configuring VLANs.
NOTE
To enable Layer 2 forwarding, use the no route-only command. On Brocade NetIron CES devices,
Layer 2 forwarding is enabled by default.
VLAN ID range
The upper range of VLAN IDs available for user VLANs (including the default VLAN) has been
reduced to 4090 (formerly 4094). The VLAN ID range above 4090 has been reserved for current
and future features for internal control purposes.
Tagged VLANs
When configuring VLANs across multiple devices, you need to use tagging only if a port connecting
one of the devices to the other is a member of more than one port-based VLAN. If you are
configuring tagged VLANs across multiple devices, make sure all the devices support the same tag
format.
VLAN hierarchy
A hierarchy of VLANs exists between the Layer 2 and Layer 3 protocol-based VLANs:
• Port-based VLANs are at the lowest level of the hierarchy.
• Layer 3 protocol-based VLANs are at the highest level of the hierarchy.
As a Brocade device receives packets, the VLAN classification starts from the highest level VLAN
first. Therefore, if an interface is configured as a member of a port-based VLAN and a
protocol-based VLAN, packets coming into the interface are classified as members of the
protocol-based VLAN because that VLAN is higher in the VLAN hierarchy.
When a port in a VLAN receives a packet, the device forwards the packet based on the following
VLAN hierarchy: