Understanding the IP
tagging feature
In a networked environment, the
same IP addresses can be reused across multiple systems (devices) running in
separate networks. These IP addresses, known as overlapping IP addresses, are
prominent in MPLS VPN environments and in networks centrally managed by Managed
Service Providers, where private IP networks of customers often deploy
identically numbered IP address spaces.
Example of an
overlapping IP in an MPLS VPN network is an example of an overlapping IP
address in an MPLS VPN network.
Example of an
overlapping IP in an MPLS VPN network

Overlapping IP addresses do not
create problems across different networks; however, when a service-assurance
application for a centrally managed network attempts to discover the
overlapping IP addresses, IP address identity problems arise. For example,
without the IP tagging feature, the
IP Manager
will
respond as follows when it discovers an overlapping IP address:
- Create a DuplicateIP notification and a DuplicateIP object.
- Discard the most recently received overlapping address.
- Remove the initially received overlapping address from its repository.With the IP tagging feature, theIP Manageris able to distinguish between overlapping addresses belonging to different customers by adding a distinguishing tag to their names.That is, instead of using the standard naming scheme of “IP-<IP address>” to name an overlapping IP address instance, theIP Manageruses the “IP-<IP address>/<tag>” naming scheme to name the instance.