Configuration Guide User guide

738 FastIron Configuration Guide
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VLAN overview
VLAN overview
The following sections provide details about the VLAN types and features supported on the FastIron
family of switches.
Types of VLANs
This section describes the VLAN types supported on Brocade devices.
VLAN support on FastIron devices
You can configure the following types of VLANs on FastIron devices:
• Layer 2 port-based VLAN – a set of physical ports that share a common, exclusive Layer 2
broadcast domain
• Layer 3 protocol VLANs – a subset of ports within a port-based VLAN that share a common,
exclusive broadcast domain for Layer 3 broadcasts of the specified protocol type
• IP subnet VLANs – a subset of ports in a port-based VLAN that share a common, exclusive
subnet broadcast domain for a specified IP subnet
• IPv6 VLANs – a subset of ports in a port-based VLAN that share a common, exclusive network
broadcast domain for IPv6 packets
• IPX network VLANs – a subset of ports in a port-based VLAN that share a common, exclusive
network broadcast domain for a specified IPX network
• AppleTalk cable VLANs – a subset of ports in a port-based-based VLAN that share a common,
exclusive network broadcast domain for a specified AppleTalk cable range
When a FastIron device receives a packet on a port that is a member of a VLAN, the device
forwards the packet based on the following VLAN hierarchy:
• If the port belongs to an IP subnet VLAN, IPX network VLAN, or AppleTalk cable VLAN and the
packet belongs to the corresponding IP subnet, IPX network, or AppleTalk cable range, the
device forwards the packet to all the ports within that VLAN.
• If the packet is a Layer 3 packet but cannot be forwarded as described above, but the port is a
member of a Layer 3 protocol VLAN for the packet protocol, the device forwards the packet on
all the Layer 3 protocol VLAN ports.
• If the packet cannot be forwarded based on either of the VLAN membership types listed above,
but the packet can be forwarded at Layer 2, the device forwards the packet on all the ports
within the receiving port port-based VLAN.
Protocol VLANs differ from IP subnet, IPX network, and AppleTalk VLANs in an important way.
Protocol VLANs accept any broadcast of the specified protocol type. An IP subnet, IPX network, or
AppleTalk VLAN accepts only broadcasts for the specified IP subnet, IPX network, or AppleTalk
cable range.
NOTE
Protocol VLANs are different from IP subnet, IPX network, and AppleTalk cable VLANs. A port-based
VLAN cannot contain both an IP subnet, IPX network, or AppleTalk cable VLAN and a protocol VLAN
for the same protocol. For example, a port-based VLAN cannot contain both an IP protocol VLAN and
an IP subnet VLAN.