3Com 3500 manual Defines an IP interface, Valid Minimum Abbreviation

ip interface define (3500/9000 Layer 3) 403

ip interface define (3500/9000 Layer 3)

✓3500

✓9000

9400

3900

9300

For CoreBuilder 9000: Applies to Layer 3 switching modules only.

Defines an IP interface.

Valid Minimum Abbreviation

ip i def

Important Considerations

■When you define an IP interface, you must decide whether you want the interface to use router port-based routing or VLAN-based routing.

■Router port-based routing directs the system to attempt to route the frame before it attempts to bridge the frame.

When you set up a router port-based IP interface, the system automatically creates a virtual LAN (VLAN) for the interface. The system assigns the next available VLAN index number to this VLAN.

■VLAN-based routing directs the system to attempt to bridge the frame before it attempts to route the frame.

When you set up a VLAN-based IP interface, you must first define a VLAN and select IP as a protocol supported by the VLAN, as described in Chapter 14.

If you define a router port, you do not have to define the VLAN first; the corresponding single-port VLAN is automatically defined.

■Port-based routing uses allClosed mode; VLAN-based routing uses either allClosed or allOpen mode. If you attempt to set up a router port-based IP interface in allOpen mode, the system notifies you with a message that it will change the VLAN mode to allClosed and recreate the default VLAN, clearing your existing VLANs in the process. Then the system prompts you to continue. (See the port-based router example at the end of this command description.)

■You cannot define a port-based IP interface on a port that is already a member of a VLAN-based IP interface. To change from one type of interface to another, you must redefine all IP interfaces and VLANs that are associated with that port.

CAUTION: Using different routing models (port-based or VLAN-based) in the same network without careful planning can adversely affect your network operations. Be sure that you understand the potential effects of router port-based and VLAN-based routing on your network. See the Implementation Guide for the CoreBuilder 3500 and for the CoreBuilder 9000 for detailed information about IP interfaces and VLANs.