Dell PowerConnect B-RX Configuration Manual page 239

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 device and other devices.
You can configure up to eight loopback interfaces on a device.
You can add up to 24 IP addresses to each loopback interface.
NOTE
If you configure the device to use a loopback interface to communicate with a BGP4 neighbor, you
also must configure a loopback interface on the neighbor and configure the neighbor to use that
loopback interface to communicate with the device. Refer to
page 791 in the BGP4 chapter.
To add a loopback interface, enter commands such as those shown in the following example.
BigIron RX(config-bgp-router)# exit
BigIron RX(config)# int loopback 1
BigIron RX(config-lbif-1)# ip address 10.0.0.1/24
Syntax: interface loopback <num>
For the syntax of the IP address, refer to
page 162.
Assigning an IP address to a virtual interface
A virtual interface is a logical port associated with a Layer 3 Virtual LAN (VLAN) configured on a
device.
NOTE
Other sections in this chapter that describe how to configure interface parameters also apply to
virtual interfaces.
NOTE
The device uses the lowest MAC address on the device (the MAC address of port 1 or 1/1) as the
MAC address for all ports within all virtual interfaces you configure on the device.
To add a virtual interface to a VLAN and configure an IP address on the interface, enter commands
such as the following.
BigIron RX(config)# vlan 2 name IP-Subnet_1.1.2.0/24
BigIron RX(config-vlan-2)# untag e1/1 to 1/4
BigIron RX(config-vlan-2)# router-interface ve1
BigIron RX(config-vlan-2)# interface ve1
BigIron RX(config-vif-1)# ip address 1.1.2.1/24
The first two commands create a Layer 3 protocol-based VLAN named "IP-Subnet_1.1.2.0/24" 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>
BigIron RX Series Configuration Guide
53-1002253-01
Configuring IP parameters
"Adding a loopback interface"
"Assigning an IP address to an Ethernet port"
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