In a networked environment, the same IP addresses can be reused across multiple systems that are running in separate networks. These IP addresses are known as overlapping or duplicate IP addresses. 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.
By default, and assuming that IP tagging is not in effect, the IP Manager will respond as follows when it discovers an overlapping IP address:
Classifies the IP address as a DuplicateIP.
Suspends IP-related analysis for the address.
Creates a DuplicateIP object.
Generates a DuplicateIP notification.
With the IP tagging feature, the IP Manager is 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, the IP Manager uses the “IP-<IP address>/<tag>” naming scheme to name the instance.
For a similar scenario in an IPv6 network, the IP Manager classifies the IPv6 address as a DuplicateIP, suspends IPv6-related analysis for the address, creates a DuplicateIPv6 object, and generates a DuplicateIPv6 notification.
By default, the IP Manager does not poll an address that is associated with a DuplicateIP or DuplicateIPv6 object. The reason is that the IP Manager has no way to determine which of the systems that are bound to that address is responding to the ICMP or SNMP polls.