Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 371)

NOTE
You cannot have a protocol-based VLAN and a subnet or network VLAN of the same protocol type in
the same port-based VLAN. For example, you can have an IPX protocol VLAN and IP subnet VLAN in
the same port-based VLAN, but you cannot have an IP protocol VLAN and an IP subnet VLAN in the
same port-based VLAN, nor can you have an IPX protocol VLAN and an IPX network VLAN in the same
port-based VLAN.
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 both a port-based VLAN and an IP protocol
VLAN, IP packets coming into the interface are classified as members of the IP protocol VLAN because
that VLAN is higher in the VLAN hierarchy.
Multiple VLAN membership rules
• A port can belong to multiple, unique, overlapping Layer 3 protocol-based VLANs without VLAN
tagging.
• A port can belong to multiple, overlapping Layer 2 port-based VLANs only if the port is a tagged port.
Packets sent out of a tagged port use an 802.1Q-tagged frame.
• When both port and protocol-based VLANs are configured on a given device, all protocol VLANs
must be strictly contained within a port-based VLAN. A protocol VLAN cannot include ports from
multiple port-based VLANs. This rule is required to ensure that port-based VLANs remain loop-free
Layer 2 broadcast domains.
• IP protocol VLANs and IP subnet VLANs cannot operate concurrently on the system or within the
same port-based VLAN.
• IPX protocol VLANs and IPX network VLANs cannot operate concurrently on the system or within the
same port-based VLAN.
• If you first configure IP and IPX protocol VLANs before deciding to partition the network by IP subnet
and IPX network VLANs, then you need to delete those VLANs before creating the IP subnet and
IPX network VLANs.
• One of each type of protocol VLAN is configurable within each port-based VLAN on the Layer 2
Switch.
• Multiple IP subnet and IPX network VLANs are configurable within each port-based VLAN on the
Layer 2 Switch.
• Removing a configured port-based VLAN from a Brocade Communication Systems, Inc Layer 2
Switch or Layer 3 Switch automatically removes any protocol-based VLAN, IP subnet VLAN,
AppleTalk cable VLAN, or IPX network VLAN, or any Virtual Ethernet router interfaces defined within
the Port-based VLAN.
Routing between VLANs
Brocade Layer 3 Switches can locally route IP, IPX, and Appletalk between VLANs defined within a
single router. All other routable protocols or protocol VLANs (for example, DecNet) must be routed by
another external router capable of routing the protocol.
Virtual routing interfaces (Layer 2 Switches only)
You need to configure virtual routing interfaces if an IP, IPX, or Appletalk protocol VLAN, IP subnet
VLAN, AppleTalk cable VLAN, or IPX network VLAN needs to route protocols to another port-based
Multiple VLAN membership rules
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