Reference Guide

Preparing Your Systems for Clustering 25
• Anycast addresses — Anycast addresses used for one-to-one-of-many
communication. In Anycast addressing an IP packet is sent to the nearest
member in a group.
Unicast Addresses have the following types:
1
Global unicast addresses — This address can be identified by format
prefix (FP) of
001 . The global unicast addresses are equivalent to
public IPv4 addresses and can be used for Public Interfaces. They are
globally routable and reachable on the IPv6 portion of Internet. The
128 bits of the unicast address space can be divided into three sections:
• Prefix — The network ID or prefix of the address, used for routing.
The first 48 bits are used for prefix.
• Subnet Identifier — A number that identifies a subnet within a site.
After the Prefix, 16 bits are used for Subnet ID.
• Interface ID — Unique identifier for a particular interface (host or
other device). This ID is unique within the specific prefix and subnet.
After the Subnet ID, the 64 bits are used for Interface ID.
2 Link local addresses — Identified by format prefix (FP) of 1111 1110 10.
These addresses are used by nodes when they are communicating with
neighboring nodes on the same link. Dynamic registrations do not occur
for link local addresses and therefore cannot be used in a cluster.
3 Site Local addresses — Identified by format prefix (FP) of 1111 1110 11.
These addresses are equivalent to IPv4 private address space. Use these
addresses between nodes that communicate with other nodes in the
same site.
Creating Separate Subnets for the Public and Private Networks
The NICs that are configured for the public and private networks and are
installed in the same cluster node must reside on separate IP subnetworks.
Therefore, the private network used to exchange heartbeat information
between the nodes must have a separate IP subnet or a different network ID
than the public network, which is used for client connections.