Public, Virtual, Private, SCAN, HAIP in RAC enviornment

In an Oracle RAC environment

• Public:  Add in the /etc/hosts, register with DNS, same subnet with Virtual and Scan IPs, and pingable
• Virtual: Add in the /etc/hosts, register with DNS, same subnet with public and scan, not pingable 
• Private:   Add in the /etc/hosts and pingable

10.125.70.171    lldvdba02.cbm.com                        lldvdba02

10.125.70.172    lldvdba02-vip.cbm.com                  lldvdba02-vip

172.115.72.130  lldvdba02-priv.cbm.com                 lldvdba02-priv

•    SCAN :  Register in DNS, Not in /etc/hosts, not pingable

nslookup dbapoc-scan

Server:         10.250.129.79

Address:        10.250.129.79#53

Name:   dbapoc-scan.cbm.com

Address: 10.125.70.200

Name:   dbapoc-scan.cbm.com

Address: 10.125.70.201

Name:   dbapoc-scan.cbm.com

Address: 10.125.70.202

• HAIP (High Availability IPs):  new in 11.2.0.2.   According to metalink source, HAIP is the redundant interconnect (bond, ipmp or similar).  Multiple private network adapters can be defined either during the installation phase or after using the oifcfg.  Grid Infrastructure can activate a maximum of 4 private network adapters at a time even if more are defeined.  The ora.cluster_interconnect_haip will start one to 4 link local HAIP on private network adapters for interconnect communication for Oracle RAC, ASM, ACFS,etc.  Grid automatically picks link local addresses from reserved 169.254.*.* subnet for HAIP, and it will not attempt to use any 169.254*.* address if it's already in use for another purpose.  With HAIP, by default, interconnect traffic will be load balanced across all active interconnect interfaces, and corresponding HAIP address will be failed over transparently to other adapters if one fails and becomes non-communicative.  the number of HAIP addresses is decided by how many private network adapters are active when Grid comes up on the first node in the cluster.  If there's only one active private network, Grid will create one; if two, Grid will create two; and if more than two, Grid will create 4 HAIPs.  The number of HAIPs won't change even if more private network adapters are activated later, a restart of clusterware on all nodes is required for new adapters to become effective.
•  Network group will need to assign IP addresses for Public, Virtual, and SCAN then register them with DNS.