@pritam.sahota - We decided to add a field "IP Addresses" which is a slushbucket pulling from cmdb_ci_ip_address table. This worked for us instead of using related list.
@bookerc - A CI for each IP is a matter of what you want to consider a CI. If you think IP addresses are CI's than yes, but you could consider an IP address an attribute of a CI such as a server or virtual machine. If that is the case than it can be just stored on your CI that has this IP address.
Really a matter of preference.
