Protocol-Based Vlans; Important Considerations - 3Com corebuilder 3500 Implementation Manual

186 C 9: V
HAPTER IRTUAL
Protocol-based
VLANs
Important
Considerations
LAN
S
Protocol-based VLANs enable you to use protocol type and bridge ports
as the distinguishing characteristics for your VLANs. When you select a
protocol such as IP, you do so based on the guidelines in this section.
Before you create this type of VLAN interface, review these guidelines:
If you plan to use the VLAN for bridging purposes, select one or more
protocols per VLAN. Select them one protocol at a time.
If you plan to use the VLAN for routing, select one or more protocols
per VLAN, one protocol at a time, and subsequently define a routing
interface for each routable protocol that is associated with the VLAN.
The system supports routing for three protocols: IP, IPX, and AppleTalk.
To define a protocol-based VLAN interface, specify this information:
The VID of your choice (except 1 or any VID already assigned), or
accept the next available VID.
The bridge ports that are part of the VLAN interface. (If you have
trunk ports, specify the anchor port for the trunk.)
The protocol for the specified ports in the VLAN.
Tag status (none or IEEEE 802.1Q). IEEE 802.1Q tagging must be
selected for ports that overlap on both port and protocol (for
example, if two IPX VLANs overlap on port 3).
The name you want to assign to this VLAN interface.
If you use IP as the protocol and also specify a Layer 3 address, the
protocol-based VLAN becomes a network-based VLAN.
You can either configure network-based IP VLANs (IP VLANs with unique
Layer 3 IP addresses) or you can define a single protocol-based VLAN with
the protocol type IP and then define multiple IP routing interfaces for that
VLAN. For more information on network-based VLANs, see
"Network-based IP VLANs" later in this chapter. For more information
about IP interfaces, see in Chapter 11.