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Configuring Ethernet Interfaces

Ethernet Interfaces

Configuring the Ethernet Interface as an Unnumbered

Interface

To conserve IP addresses on your network, you may want to create the

Ethernet interface as an unnumbered interface. When you assign the Ethernet

interface an IP address, that IP address cannot overlap with the IP addresses

assigned to other interfaces on the router. As a result, each interface on the

router that has an IP address represents an entire subnet. Depending on the

subnetting scheme you use, this could use more IP addresses than you

can spare.

You can configure the Ethernet interface (and other interfaces on the

ProCurve Secure Router) as an unnumbered interface. The Ethernet interface

will then use the IP address of the interface you specify. The Secure Router

OS uses the IP address of the specified interface when sending route updates

over the unnumbered interface.

Before configuring the Ethernet interface as an unnumbered interface, you

should be aware of a potential disadvantage: if the interface to which the IP

address is actually assigned goes down, the Ethernet interface will be unavail-

able. For example, suppose you configure the Ethernet 0/1 interface as an

unnumbered interface that takes its IP address from the Frame Relay 1.16

subinterface. If the Frame Relay 1.16 subinterface goes down, the Ethernet

0/1 interface will be unavailable as well.

To minimize the chances of the interface with the IP address going down, you

can assign the IP address to a loopback interface, which typically does not

go down.

To configure an Ethernet interface as an unnumbered interface, enter the

following command from the Ethernet interface configuration mode context:

Syntax: ip unnumbered <interface>

Valid interfaces include:

■ Asynchronous Transfer Mode (ATM) subinterfaces

■ the other Ethernet interface or Ethernet subinterfaces

■ demand interfaces

■ Frame Relay subinterfaces

■ High-level Data Link Control (HDLC) interfaces

■ loopback interfaces

■ PPP interfaces

HP ProCurve 7000dl Series User Manual

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