IBM 4002-Y2A, Installation And User Manual

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Assigning an IP address to a loopback interface: Loopback interfaces are always
up, regardless of the states of physical interfaces. They can add stability to the
network because they are not subject to route flap problems that can occur due to
unstable links between a Layer 3 Switch and other devices. You can configure up
to four loopback interfaces on a Layer 3 switch.
You can add up to 24 IP addresses to each loopback interface.
Note: If you configure the y-series switch to use a loopback interface to
communicate with a BGP4 neighbor, you must also configure a loopback
interface on the neighbor and configure the neighbor to use that loopback
interface to communicate with the y-series switch.
To add a loopback interface, enter commands such as those shown in the following
example:
FCX624 Router(config)# exit
FCX624 Router(config)# int loopback 1
FCX624 Router(config-lbif-1)# ip address 10.0.0.1/24
Syntax: interface loopback <num>
The <num> parameter specifies the virtual interface number. You can specify from
1 to the maximum number of virtual interfaces supported on the device. To display
the maximum number of virtual interfaces supported on the device, enter the
show default values command. The maximum is listed in the System Parameters
section, in the Current column of the virtual-interface row.
Assigning an IP address to a virtual routing interface:
A virtual interface is a
logical port associated with a Layer 3 Virtual LAN (VLAN) configured on a Layer
3 switch. You can configure routing parameters on the virtual interface to enable
the Layer 3 switch to route protocol traffic from one Layer 3 VLAN to the other,
without using an external router.
This section describes how to configure an IP address on a virtual interface.
Note: The switch uses the lowest MAC address on the device (the MAC address of
port 1 or 1/1/1) as the MAC address for all ports within all virtual
interfaces you configure on the device.
Enter commands similar to the following to add a virtual interface to a VLAN and
configure an IP address on the interface.
FCX624 Router(config)# vlan 2 name IP-Subnet_1.1.2.1/24
FCX624 Router(config-vlan-2)# untag 1/1/1 to 1/1/4
FCX624 Router(config-vlan-2)# router-interface ve1
FCX624 Router(config-vlan-2)# interface ve1
FCX624 Router(config-vif-1)# ip address 1.1.2.1/24
The first two commands in this example create a Layer 3 protocol-based VLAN
name “IP-Subnet_1.1.2.1/24” and add a range of untagged ports to the VLAN. The
router-interface command creates virtual interface 1 as the routing interface for the
VLAN. The last two commands change to the interface configuration level for the
virtual interface and assign an IP address to the interface.
Syntax: router-interface ve <num>
Syntax: interface ve <num>
Deleting an IP address
Enter a command similar to the following to delete an IP address.
FCX624 Router(config-if-1/1/1)# no ip address 1.1.2.1
Chapter 3. Checking network devices and testing connectivity
33