Loopback Interface

Overview

The loopback interface is a virtual interface whose operational state is always up. If the IP address that is configured on this virtual interface is used as the local address when communicating with remote IP applications, the communication will not be aborted even if the actual route to the remote application was changed.

The operational state of a loopback interface is always up. You define an IP address (either IPv4 or IPv6) on it and use this IP address as the local IP address for IP communication with remote IP applications.

A loopback interface does not support bridging; it cannot be a member of any VLAN, and no layer 2 protocol can be enabled on it.

The IPv6 link-local interface identifier is 1.

When the switch is in Layer 2 system mode, the following rules are supported:

• Only one loopback interface is supported.
• Two IPv4 interfaces can be configured: one on a VLAN or Ethernet port and one on the loopback interface.
• If the IPv4 address was configured on the default VLAN and the default VLAN is changed, the switch moves the IPv4 address to the new default VLAN.