IPv6 loopback interfaces

By default, each switch has eight internal IPv6 loopback interfaces (lo-0 as through lo-7) with IPv6 address ::1/128 configured by default on lo-0. This address (::1/128) is used only for internal traffic transmitted within the switch and is not used in packet headers in egress traffic sent to network devices.

Each loopback interface can have multiple IPv6 addresses, all of which must be unique. Routing protocols such as OSPFv3, advertise the configured loopback addresses throughout a network or autonomous system.

User-defined IPv6 loopback addresses provide these benefits when a routing protocol is enabled:
  • A loopback interface is a virtual interface that is always up and reachable as long as at least one of the IPv6 interfaces on the switch is operational. As a result, a loopback interface is useful for debugging tasks because its address can always be pinged if any other switch interface is up.

  • You can use a loopback interface to establish a Telnet session, ping the switch, and access the switch through SNMP.