This is the rn (Relative Name), the single naming segment that, appended to its parent's dn, forms the full dn for this one instance of an IPv6 address that has been drawn from an IPv6 pool and pooled for possible assignment, tracked separately from the block it came from. UCS Manager derives this segment automatically from the object's own defining attribute (such as an address, index, or configured name), so seeing a distinctive rn like this is how you tell one IpV6Pooled row apart from every sibling row under the same parent. For this class the rn typically looks like 'pooled-2001:db8::40'.